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-rw-r--r--SOURCES/tkg-prjc_v6.7-r2.patch11478
1 files changed, 11478 insertions, 0 deletions
diff --git a/SOURCES/tkg-prjc_v6.7-r2.patch b/SOURCES/tkg-prjc_v6.7-r2.patch
new file mode 100644
index 0000000..9d5b0ee
--- /dev/null
+++ b/SOURCES/tkg-prjc_v6.7-r2.patch
@@ -0,0 +1,11478 @@
+diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
+index 6584a1f9bfe3..226c79dd34cc 100644
+--- a/Documentation/admin-guide/sysctl/kernel.rst
++++ b/Documentation/admin-guide/sysctl/kernel.rst
+@@ -1646,3 +1646,13 @@ is 10 seconds.
+
+ The softlockup threshold is (``2 * watchdog_thresh``). Setting this
+ tunable to zero will disable lockup detection altogether.
++
++yield_type:
++===========
++
++BMQ/PDS CPU scheduler only. This determines what type of yield calls
++to sched_yield() will be performed.
++
++ 0 - No yield.
++ 1 - Requeue task. (default)
++ 2 - Set run queue skip task. Same as CFS.
+diff --git a/Documentation/scheduler/sched-BMQ.txt b/Documentation/scheduler/sched-BMQ.txt
+new file mode 100644
+index 000000000000..05c84eec0f31
+--- /dev/null
++++ b/Documentation/scheduler/sched-BMQ.txt
+@@ -0,0 +1,110 @@
++ BitMap queue CPU Scheduler
++ --------------------------
++
++CONTENT
++========
++
++ Background
++ Design
++ Overview
++ Task policy
++ Priority management
++ BitMap Queue
++ CPU Assignment and Migration
++
++
++Background
++==========
++
++BitMap Queue CPU scheduler, referred to as BMQ from here on, is an evolution
++of previous Priority and Deadline based Skiplist multiple queue scheduler(PDS),
++and inspired by Zircon scheduler. The goal of it is to keep the scheduler code
++simple, while efficiency and scalable for interactive tasks, such as desktop,
++movie playback and gaming etc.
++
++Design
++======
++
++Overview
++--------
++
++BMQ use per CPU run queue design, each CPU(logical) has it's own run queue,
++each CPU is responsible for scheduling the tasks that are putting into it's
++run queue.
++
++The run queue is a set of priority queues. Note that these queues are fifo
++queue for non-rt tasks or priority queue for rt tasks in data structure. See
++BitMap Queue below for details. BMQ is optimized for non-rt tasks in the fact
++that most applications are non-rt tasks. No matter the queue is fifo or
++priority, In each queue is an ordered list of runnable tasks awaiting execution
++and the data structures are the same. When it is time for a new task to run,
++the scheduler simply looks the lowest numbered queueue that contains a task,
++and runs the first task from the head of that queue. And per CPU idle task is
++also in the run queue, so the scheduler can always find a task to run on from
++its run queue.
++
++Each task will assigned the same timeslice(default 4ms) when it is picked to
++start running. Task will be reinserted at the end of the appropriate priority
++queue when it uses its whole timeslice. When the scheduler selects a new task
++from the priority queue it sets the CPU's preemption timer for the remainder of
++the previous timeslice. When that timer fires the scheduler will stop execution
++on that task, select another task and start over again.
++
++If a task blocks waiting for a shared resource then it's taken out of its
++priority queue and is placed in a wait queue for the shared resource. When it
++is unblocked it will be reinserted in the appropriate priority queue of an
++eligible CPU.
++
++Task policy
++-----------
++
++BMQ supports DEADLINE, FIFO, RR, NORMAL, BATCH and IDLE task policy like the
++mainline CFS scheduler. But BMQ is heavy optimized for non-rt task, that's
++NORMAL/BATCH/IDLE policy tasks. Below is the implementation detail of each
++policy.
++
++DEADLINE
++ It is squashed as priority 0 FIFO task.
++
++FIFO/RR
++ All RT tasks share one single priority queue in BMQ run queue designed. The
++complexity of insert operation is O(n). BMQ is not designed for system runs
++with major rt policy tasks.
++
++NORMAL/BATCH/IDLE
++ BATCH and IDLE tasks are treated as the same policy. They compete CPU with
++NORMAL policy tasks, but they just don't boost. To control the priority of
++NORMAL/BATCH/IDLE tasks, simply use nice level.
++
++ISO
++ ISO policy is not supported in BMQ. Please use nice level -20 NORMAL policy
++task instead.
++
++Priority management
++-------------------
++
++RT tasks have priority from 0-99. For non-rt tasks, there are three different
++factors used to determine the effective priority of a task. The effective
++priority being what is used to determine which queue it will be in.
++
++The first factor is simply the task’s static priority. Which is assigned from
++task's nice level, within [-20, 19] in userland's point of view and [0, 39]
++internally.
++
++The second factor is the priority boost. This is a value bounded between
++[-MAX_PRIORITY_ADJ, MAX_PRIORITY_ADJ] used to offset the base priority, it is
++modified by the following cases:
++
++*When a thread has used up its entire timeslice, always deboost its boost by
++increasing by one.
++*When a thread gives up cpu control(voluntary or non-voluntary) to reschedule,
++and its switch-in time(time after last switch and run) below the thredhold
++based on its priority boost, will boost its boost by decreasing by one buti is
++capped at 0 (won’t go negative).
++
++The intent in this system is to ensure that interactive threads are serviced
++quickly. These are usually the threads that interact directly with the user
++and cause user-perceivable latency. These threads usually do little work and
++spend most of their time blocked awaiting another user event. So they get the
++priority boost from unblocking while background threads that do most of the
++processing receive the priority penalty for using their entire timeslice.
+diff --git a/fs/proc/base.c b/fs/proc/base.c
+index dd31e3b6bf77..12d1248cb4df 100644
+--- a/fs/proc/base.c
++++ b/fs/proc/base.c
+@@ -480,7 +480,7 @@ static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
+ seq_puts(m, "0 0 0\n");
+ else
+ seq_printf(m, "%llu %llu %lu\n",
+- (unsigned long long)task->se.sum_exec_runtime,
++ (unsigned long long)tsk_seruntime(task),
+ (unsigned long long)task->sched_info.run_delay,
+ task->sched_info.pcount);
+
+diff --git a/include/asm-generic/resource.h b/include/asm-generic/resource.h
+index 8874f681b056..59eb72bf7d5f 100644
+--- a/include/asm-generic/resource.h
++++ b/include/asm-generic/resource.h
+@@ -23,7 +23,7 @@
+ [RLIMIT_LOCKS] = { RLIM_INFINITY, RLIM_INFINITY }, \
+ [RLIMIT_SIGPENDING] = { 0, 0 }, \
+ [RLIMIT_MSGQUEUE] = { MQ_BYTES_MAX, MQ_BYTES_MAX }, \
+- [RLIMIT_NICE] = { 0, 0 }, \
++ [RLIMIT_NICE] = { 30, 30 }, \
+ [RLIMIT_RTPRIO] = { 0, 0 }, \
+ [RLIMIT_RTTIME] = { RLIM_INFINITY, RLIM_INFINITY }, \
+ }
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 292c31697248..f5b026795dc6 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -769,8 +769,14 @@ struct task_struct {
+ unsigned int ptrace;
+
+ #ifdef CONFIG_SMP
+- int on_cpu;
+ struct __call_single_node wake_entry;
++#endif
++#if defined(CONFIG_SMP) || defined(CONFIG_SCHED_ALT)
++ int on_cpu;
++#endif
++
++#ifdef CONFIG_SMP
++#ifndef CONFIG_SCHED_ALT
+ unsigned int wakee_flips;
+ unsigned long wakee_flip_decay_ts;
+ struct task_struct *last_wakee;
+@@ -784,6 +790,7 @@ struct task_struct {
+ */
+ int recent_used_cpu;
+ int wake_cpu;
++#endif /* !CONFIG_SCHED_ALT */
+ #endif
+ int on_rq;
+
+@@ -792,6 +799,20 @@ struct task_struct {
+ int normal_prio;
+ unsigned int rt_priority;
+
++#ifdef CONFIG_SCHED_ALT
++ u64 last_ran;
++ s64 time_slice;
++ int sq_idx;
++ struct list_head sq_node;
++#ifdef CONFIG_SCHED_BMQ
++ int boost_prio;
++#endif /* CONFIG_SCHED_BMQ */
++#ifdef CONFIG_SCHED_PDS
++ u64 deadline;
++#endif /* CONFIG_SCHED_PDS */
++ /* sched_clock time spent running */
++ u64 sched_time;
++#else /* !CONFIG_SCHED_ALT */
+ struct sched_entity se;
+ struct sched_rt_entity rt;
+ struct sched_dl_entity dl;
+@@ -802,6 +823,7 @@ struct task_struct {
+ unsigned long core_cookie;
+ unsigned int core_occupation;
+ #endif
++#endif /* !CONFIG_SCHED_ALT */
+
+ #ifdef CONFIG_CGROUP_SCHED
+ struct task_group *sched_task_group;
+@@ -1561,6 +1583,15 @@ struct task_struct {
+ */
+ };
+
++#ifdef CONFIG_SCHED_ALT
++#define tsk_seruntime(t) ((t)->sched_time)
++/* replace the uncertian rt_timeout with 0UL */
++#define tsk_rttimeout(t) (0UL)
++#else /* CFS */
++#define tsk_seruntime(t) ((t)->se.sum_exec_runtime)
++#define tsk_rttimeout(t) ((t)->rt.timeout)
++#endif /* !CONFIG_SCHED_ALT */
++
+ static inline struct pid *task_pid(struct task_struct *task)
+ {
+ return task->thread_pid;
+diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h
+index df3aca89d4f5..1df1f7635188 100644
+--- a/include/linux/sched/deadline.h
++++ b/include/linux/sched/deadline.h
+@@ -2,6 +2,25 @@
+ #ifndef _LINUX_SCHED_DEADLINE_H
+ #define _LINUX_SCHED_DEADLINE_H
+
++#ifdef CONFIG_SCHED_ALT
++
++static inline int dl_task(struct task_struct *p)
++{
++ return 0;
++}
++
++#ifdef CONFIG_SCHED_BMQ
++#define __tsk_deadline(p) (0UL)
++#endif
++
++#ifdef CONFIG_SCHED_PDS
++#define __tsk_deadline(p) ((((u64) ((p)->prio))<<56) | (p)->deadline)
++#endif
++
++#else
++
++#define __tsk_deadline(p) ((p)->dl.deadline)
++
+ /*
+ * SCHED_DEADLINE tasks has negative priorities, reflecting
+ * the fact that any of them has higher prio than RT and
+@@ -23,6 +42,7 @@ static inline int dl_task(struct task_struct *p)
+ {
+ return dl_prio(p->prio);
+ }
++#endif /* CONFIG_SCHED_ALT */
+
+ static inline bool dl_time_before(u64 a, u64 b)
+ {
+diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
+index ab83d85e1183..a9a1dfa99140 100644
+--- a/include/linux/sched/prio.h
++++ b/include/linux/sched/prio.h
+@@ -18,6 +18,32 @@
+ #define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
+ #define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
+
++#ifdef CONFIG_SCHED_ALT
++
++/* Undefine MAX_PRIO and DEFAULT_PRIO */
++#undef MAX_PRIO
++#undef DEFAULT_PRIO
++
++/* +/- priority levels from the base priority */
++#ifdef CONFIG_SCHED_BMQ
++#define MAX_PRIORITY_ADJ (12)
++
++#define MIN_NORMAL_PRIO (MAX_RT_PRIO)
++#define MAX_PRIO (MIN_NORMAL_PRIO + NICE_WIDTH)
++#define DEFAULT_PRIO (MIN_NORMAL_PRIO + NICE_WIDTH / 2)
++#endif
++
++#ifdef CONFIG_SCHED_PDS
++#define MAX_PRIORITY_ADJ (0)
++
++#define MIN_NORMAL_PRIO (128)
++#define NORMAL_PRIO_NUM (64)
++#define MAX_PRIO (MIN_NORMAL_PRIO + NORMAL_PRIO_NUM)
++#define DEFAULT_PRIO (MAX_PRIO - NICE_WIDTH / 2)
++#endif
++
++#endif /* CONFIG_SCHED_ALT */
++
+ /*
+ * Convert user-nice values [ -20 ... 0 ... 19 ]
+ * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
+diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h
+index b2b9e6eb9683..09bd4d8758b2 100644
+--- a/include/linux/sched/rt.h
++++ b/include/linux/sched/rt.h
+@@ -24,8 +24,10 @@ static inline bool task_is_realtime(struct task_struct *tsk)
+
+ if (policy == SCHED_FIFO || policy == SCHED_RR)
+ return true;
++#ifndef CONFIG_SCHED_ALT
+ if (policy == SCHED_DEADLINE)
+ return true;
++#endif
+ return false;
+ }
+
+diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
+index de545ba85218..941bb18ff72c 100644
+--- a/include/linux/sched/topology.h
++++ b/include/linux/sched/topology.h
+@@ -238,7 +238,8 @@ static inline bool cpus_share_resources(int this_cpu, int that_cpu)
+
+ #endif /* !CONFIG_SMP */
+
+-#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
++#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) && \
++ !defined(CONFIG_SCHED_ALT)
+ extern void rebuild_sched_domains_energy(void);
+ #else
+ static inline void rebuild_sched_domains_energy(void)
+diff --git a/init/Kconfig b/init/Kconfig
+index 9ffb103fc927..8f0b7eeff77e 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -629,6 +629,7 @@ config TASK_IO_ACCOUNTING
+
+ config PSI
+ bool "Pressure stall information tracking"
++ depends on !SCHED_ALT
+ select KERNFS
+ help
+ Collect metrics that indicate how overcommitted the CPU, memory,
+@@ -794,6 +795,7 @@ menu "Scheduler features"
+ config UCLAMP_TASK
+ bool "Enable utilization clamping for RT/FAIR tasks"
+ depends on CPU_FREQ_GOV_SCHEDUTIL
++ depends on !SCHED_ALT
+ help
+ This feature enables the scheduler to track the clamped utilization
+ of each CPU based on RUNNABLE tasks scheduled on that CPU.
+@@ -840,6 +842,35 @@ config UCLAMP_BUCKETS_COUNT
+
+ If in doubt, use the default value.
+
++menuconfig SCHED_ALT
++ bool "Alternative CPU Schedulers"
++ default y
++ help
++ This feature enable alternative CPU scheduler"
++
++if SCHED_ALT
++
++choice
++ prompt "Alternative CPU Scheduler"
++ default SCHED_BMQ
++
++config SCHED_BMQ
++ bool "BMQ CPU scheduler"
++ help
++ The BitMap Queue CPU scheduler for excellent interactivity and
++ responsiveness on the desktop and solid scalability on normal
++ hardware and commodity servers.
++
++config SCHED_PDS
++ bool "PDS CPU scheduler"
++ help
++ The Priority and Deadline based Skip list multiple queue CPU
++ Scheduler.
++
++endchoice
++
++endif
++
+ endmenu
+
+ #
+@@ -893,6 +924,7 @@ config NUMA_BALANCING
+ depends on ARCH_SUPPORTS_NUMA_BALANCING
+ depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
+ depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
++ depends on !SCHED_ALT
+ help
+ This option adds support for automatic NUMA aware memory/task placement.
+ The mechanism is quite primitive and is based on migrating memory when
+@@ -990,6 +1022,7 @@ config FAIR_GROUP_SCHED
+ depends on CGROUP_SCHED
+ default CGROUP_SCHED
+
++if !SCHED_ALT
+ config CFS_BANDWIDTH
+ bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
+ depends on FAIR_GROUP_SCHED
+@@ -1012,6 +1045,7 @@ config RT_GROUP_SCHED
+ realtime bandwidth for them.
+ See Documentation/scheduler/sched-rt-group.rst for more information.
+
++endif #!SCHED_ALT
+ endif #CGROUP_SCHED
+
+ config SCHED_MM_CID
+@@ -1260,6 +1294,7 @@ config CHECKPOINT_RESTORE
+
+ config SCHED_AUTOGROUP
+ bool "Automatic process group scheduling"
++ depends on !SCHED_ALT
+ select CGROUPS
+ select CGROUP_SCHED
+ select FAIR_GROUP_SCHED
+diff --git a/init/init_task.c b/init/init_task.c
+index 5727d42149c3..e2e2622d50d5 100644
+--- a/init/init_task.c
++++ b/init/init_task.c
+@@ -75,9 +75,15 @@ struct task_struct init_task
+ .stack = init_stack,
+ .usage = REFCOUNT_INIT(2),
+ .flags = PF_KTHREAD,
++#ifdef CONFIG_SCHED_ALT
++ .prio = DEFAULT_PRIO + MAX_PRIORITY_ADJ,
++ .static_prio = DEFAULT_PRIO,
++ .normal_prio = DEFAULT_PRIO + MAX_PRIORITY_ADJ,
++#else
+ .prio = MAX_PRIO - 20,
+ .static_prio = MAX_PRIO - 20,
+ .normal_prio = MAX_PRIO - 20,
++#endif
+ .policy = SCHED_NORMAL,
+ .cpus_ptr = &init_task.cpus_mask,
+ .user_cpus_ptr = NULL,
+@@ -89,6 +95,17 @@ struct task_struct init_task
+ .restart_block = {
+ .fn = do_no_restart_syscall,
+ },
++#ifdef CONFIG_SCHED_ALT
++ .sq_node = LIST_HEAD_INIT(init_task.sq_node),
++#ifdef CONFIG_SCHED_BMQ
++ .boost_prio = 0,
++ .sq_idx = 15,
++#endif
++#ifdef CONFIG_SCHED_PDS
++ .deadline = 0,
++#endif
++ .time_slice = HZ,
++#else
+ .se = {
+ .group_node = LIST_HEAD_INIT(init_task.se.group_node),
+ },
+@@ -96,6 +113,7 @@ struct task_struct init_task
+ .run_list = LIST_HEAD_INIT(init_task.rt.run_list),
+ .time_slice = RR_TIMESLICE,
+ },
++#endif
+ .tasks = LIST_HEAD_INIT(init_task.tasks),
+ #ifdef CONFIG_SMP
+ .pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
+diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
+index c2f1fd95a821..41654679b1b2 100644
+--- a/kernel/Kconfig.preempt
++++ b/kernel/Kconfig.preempt
+@@ -117,7 +117,7 @@ config PREEMPT_DYNAMIC
+
+ config SCHED_CORE
+ bool "Core Scheduling for SMT"
+- depends on SCHED_SMT
++ depends on SCHED_SMT && !SCHED_ALT
+ help
+ This option permits Core Scheduling, a means of coordinated task
+ selection across SMT siblings. When enabled -- see
+diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
+index 615daaf87f1f..16fb54ec732c 100644
+--- a/kernel/cgroup/cpuset.c
++++ b/kernel/cgroup/cpuset.c
+@@ -848,7 +848,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
+ return ret;
+ }
+
+-#ifdef CONFIG_SMP
++#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_ALT)
+ /*
+ * Helper routine for generate_sched_domains().
+ * Do cpusets a, b have overlapping effective cpus_allowed masks?
+@@ -1247,7 +1247,7 @@ static void rebuild_sched_domains_locked(void)
+ /* Have scheduler rebuild the domains */
+ partition_and_rebuild_sched_domains(ndoms, doms, attr);
+ }
+-#else /* !CONFIG_SMP */
++#else /* !CONFIG_SMP || CONFIG_SCHED_ALT */
+ static void rebuild_sched_domains_locked(void)
+ {
+ }
+@@ -3206,12 +3206,15 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
+ goto out_unlock;
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ if (dl_task(task)) {
+ cs->nr_migrate_dl_tasks++;
+ cs->sum_migrate_dl_bw += task->dl.dl_bw;
+ }
++#endif
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ if (!cs->nr_migrate_dl_tasks)
+ goto out_success;
+
+@@ -3232,6 +3235,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
+ }
+
+ out_success:
++#endif
+ /*
+ * Mark attach is in progress. This makes validate_change() fail
+ * changes which zero cpus/mems_allowed.
+@@ -3255,12 +3259,14 @@ static void cpuset_cancel_attach(struct cgroup_taskset *tset)
+ if (!cs->attach_in_progress)
+ wake_up(&cpuset_attach_wq);
+
++#ifndef CONFIG_SCHED_ALT
+ if (cs->nr_migrate_dl_tasks) {
+ int cpu = cpumask_any(cs->effective_cpus);
+
+ dl_bw_free(cpu, cs->sum_migrate_dl_bw);
+ reset_migrate_dl_data(cs);
+ }
++#endif
+
+ mutex_unlock(&cpuset_mutex);
+ }
+diff --git a/kernel/delayacct.c b/kernel/delayacct.c
+index 6f0c358e73d8..8111481ce8b1 100644
+--- a/kernel/delayacct.c
++++ b/kernel/delayacct.c
+@@ -150,7 +150,7 @@ int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+ */
+ t1 = tsk->sched_info.pcount;
+ t2 = tsk->sched_info.run_delay;
+- t3 = tsk->se.sum_exec_runtime;
++ t3 = tsk_seruntime(tsk);
+
+ d->cpu_count += t1;
+
+diff --git a/kernel/exit.c b/kernel/exit.c
+index aedc0832c9f4..ff8bf6cddc34 100644
+--- a/kernel/exit.c
++++ b/kernel/exit.c
+@@ -174,7 +174,7 @@ static void __exit_signal(struct task_struct *tsk)
+ sig->curr_target = next_thread(tsk);
+ }
+
+- add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
++ add_device_randomness((const void*) &tsk_seruntime(tsk),
+ sizeof(unsigned long long));
+
+ /*
+@@ -195,7 +195,7 @@ static void __exit_signal(struct task_struct *tsk)
+ sig->inblock += task_io_get_inblock(tsk);
+ sig->oublock += task_io_get_oublock(tsk);
+ task_io_accounting_add(&sig->ioac, &tsk->ioac);
+- sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
++ sig->sum_sched_runtime += tsk_seruntime(tsk);
+ sig->nr_threads--;
+ __unhash_process(tsk, group_dead);
+ write_sequnlock(&sig->stats_lock);
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 4a10e8c16fd2..cfbbdd64b851 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -362,7 +362,7 @@ waiter_update_prio(struct rt_mutex_waiter *waiter, struct task_struct *task)
+ lockdep_assert(RB_EMPTY_NODE(&waiter->tree.entry));
+
+ waiter->tree.prio = __waiter_prio(task);
+- waiter->tree.deadline = task->dl.deadline;
++ waiter->tree.deadline = __tsk_deadline(task);
+ }
+
+ /*
+@@ -383,16 +383,20 @@ waiter_clone_prio(struct rt_mutex_waiter *waiter, struct task_struct *task)
+ * Only use with rt_waiter_node_{less,equal}()
+ */
+ #define task_to_waiter_node(p) \
+- &(struct rt_waiter_node){ .prio = __waiter_prio(p), .deadline = (p)->dl.deadline }
++ &(struct rt_waiter_node){ .prio = __waiter_prio(p), .deadline = __tsk_deadline(p) }
+ #define task_to_waiter(p) \
+ &(struct rt_mutex_waiter){ .tree = *task_to_waiter_node(p) }
+
+ static __always_inline int rt_waiter_node_less(struct rt_waiter_node *left,
+ struct rt_waiter_node *right)
+ {
++#ifdef CONFIG_SCHED_PDS
++ return (left->deadline < right->deadline);
++#else
+ if (left->prio < right->prio)
+ return 1;
+
++#ifndef CONFIG_SCHED_BMQ
+ /*
+ * If both waiters have dl_prio(), we check the deadlines of the
+ * associated tasks.
+@@ -401,16 +405,22 @@ static __always_inline int rt_waiter_node_less(struct rt_waiter_node *left,
+ */
+ if (dl_prio(left->prio))
+ return dl_time_before(left->deadline, right->deadline);
++#endif
+
+ return 0;
++#endif
+ }
+
+ static __always_inline int rt_waiter_node_equal(struct rt_waiter_node *left,
+ struct rt_waiter_node *right)
+ {
++#ifdef CONFIG_SCHED_PDS
++ return (left->deadline == right->deadline);
++#else
+ if (left->prio != right->prio)
+ return 0;
+
++#ifndef CONFIG_SCHED_BMQ
+ /*
+ * If both waiters have dl_prio(), we check the deadlines of the
+ * associated tasks.
+@@ -419,8 +429,10 @@ static __always_inline int rt_waiter_node_equal(struct rt_waiter_node *left,
+ */
+ if (dl_prio(left->prio))
+ return left->deadline == right->deadline;
++#endif
+
+ return 1;
++#endif
+ }
+
+ static inline bool rt_mutex_steal(struct rt_mutex_waiter *waiter,
+diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
+index 976092b7bd45..31d587c16ec1 100644
+--- a/kernel/sched/Makefile
++++ b/kernel/sched/Makefile
+@@ -28,7 +28,12 @@ endif
+ # These compilation units have roughly the same size and complexity - so their
+ # build parallelizes well and finishes roughly at once:
+ #
++ifdef CONFIG_SCHED_ALT
++obj-y += alt_core.o
++obj-$(CONFIG_SCHED_DEBUG) += alt_debug.o
++else
+ obj-y += core.o
+ obj-y += fair.o
++endif
+ obj-y += build_policy.o
+ obj-y += build_utility.o
+diff --git a/kernel/sched/alt_core.c b/kernel/sched/alt_core.c
+new file mode 100644
+index 000000000000..5b6bdff6e630
+--- /dev/null
++++ b/kernel/sched/alt_core.c
+@@ -0,0 +1,8944 @@
++/*
++ * kernel/sched/alt_core.c
++ *
++ * Core alternative kernel scheduler code and related syscalls
++ *
++ * Copyright (C) 1991-2002 Linus Torvalds
++ *
++ * 2009-08-13 Brainfuck deadline scheduling policy by Con Kolivas deletes
++ * a whole lot of those previous things.
++ * 2017-09-06 Priority and Deadline based Skip list multiple queue kernel
++ * scheduler by Alfred Chen.
++ * 2019-02-20 BMQ(BitMap Queue) kernel scheduler by Alfred Chen.
++ */
++#include <linux/sched/clock.h>
++#include <linux/sched/cputime.h>
++#include <linux/sched/debug.h>
++#include <linux/sched/isolation.h>
++#include <linux/sched/loadavg.h>
++#include <linux/sched/mm.h>
++#include <linux/sched/nohz.h>
++#include <linux/sched/stat.h>
++#include <linux/sched/wake_q.h>
++
++#include <linux/blkdev.h>
++#include <linux/context_tracking.h>
++#include <linux/cpuset.h>
++#include <linux/delayacct.h>
++#include <linux/init_task.h>
++#include <linux/kcov.h>
++#include <linux/kprobes.h>
++#include <linux/nmi.h>
++#include <linux/scs.h>
++
++#include <uapi/linux/sched/types.h>
++
++#include <asm/irq_regs.h>
++#include <asm/switch_to.h>
++
++#define CREATE_TRACE_POINTS
++#include <trace/events/sched.h>
++#include <trace/events/ipi.h>
++#undef CREATE_TRACE_POINTS
++
++#include "sched.h"
++
++#include "pelt.h"
++
++#include "../../io_uring/io-wq.h"
++#include "../smpboot.h"
++
++EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpu);
++EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpumask);
++
++/*
++ * Export tracepoints that act as a bare tracehook (ie: have no trace event
++ * associated with them) to allow external modules to probe them.
++ */
++EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
++
++#ifdef CONFIG_SCHED_DEBUG
++#define sched_feat(x) (1)
++/*
++ * Print a warning if need_resched is set for the given duration (if
++ * LATENCY_WARN is enabled).
++ *
++ * If sysctl_resched_latency_warn_once is set, only one warning will be shown
++ * per boot.
++ */
++__read_mostly int sysctl_resched_latency_warn_ms = 100;
++__read_mostly int sysctl_resched_latency_warn_once = 1;
++#else
++#define sched_feat(x) (0)
++#endif /* CONFIG_SCHED_DEBUG */
++
++#define ALT_SCHED_VERSION "v6.7-r2"
++
++/*
++ * Compile time debug macro
++ * #define ALT_SCHED_DEBUG
++ */
++
++/* rt_prio(prio) defined in include/linux/sched/rt.h */
++#define rt_task(p) rt_prio((p)->prio)
++#define rt_policy(policy) ((policy) == SCHED_FIFO || (policy) == SCHED_RR)
++#define task_has_rt_policy(p) (rt_policy((p)->policy))
++
++#define STOP_PRIO (MAX_RT_PRIO - 1)
++
++/*
++ * Time slice
++ * (default: 4 msec, units: nanoseconds)
++ */
++unsigned int sysctl_sched_base_slice __read_mostly = (4 << 20);
++
++static inline void requeue_task(struct task_struct *p, struct rq *rq, int idx);
++
++#ifdef CONFIG_SCHED_BMQ
++#include "bmq.h"
++#endif
++#ifdef CONFIG_SCHED_PDS
++#include "pds.h"
++#endif
++
++struct affinity_context {
++ const struct cpumask *new_mask;
++ struct cpumask *user_mask;
++ unsigned int flags;
++};
++
++/* Reschedule if less than this many μs left */
++#define RESCHED_NS (100 << 10)
++
++/**
++ * sched_yield_type - Type of sched_yield() will be performed.
++ * 0: No yield.
++ * 1: Requeue task. (default)
++ * 2: Set rq skip task. (Same as mainline)
++ */
++int sched_yield_type __read_mostly = 1;
++
++#ifdef CONFIG_SMP
++static cpumask_t sched_rq_pending_mask ____cacheline_aligned_in_smp;
++
++DEFINE_PER_CPU_ALIGNED(cpumask_t [NR_CPU_AFFINITY_LEVELS], sched_cpu_topo_masks);
++DEFINE_PER_CPU_ALIGNED(cpumask_t *, sched_cpu_llc_mask);
++DEFINE_PER_CPU_ALIGNED(cpumask_t *, sched_cpu_topo_end_mask);
++
++#ifdef CONFIG_SCHED_SMT
++DEFINE_STATIC_KEY_FALSE(sched_smt_present);
++EXPORT_SYMBOL_GPL(sched_smt_present);
++#endif
++
++/*
++ * Keep a unique ID per domain (we use the first CPUs number in the cpumask of
++ * the domain), this allows us to quickly tell if two cpus are in the same cache
++ * domain, see cpus_share_cache().
++ */
++DEFINE_PER_CPU(int, sd_llc_id);
++#endif /* CONFIG_SMP */
++
++static DEFINE_MUTEX(sched_hotcpu_mutex);
++
++DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
++
++#ifndef prepare_arch_switch
++# define prepare_arch_switch(next) do { } while (0)
++#endif
++#ifndef finish_arch_post_lock_switch
++# define finish_arch_post_lock_switch() do { } while (0)
++#endif
++
++#ifdef CONFIG_SCHED_SMT
++static cpumask_t sched_sg_idle_mask ____cacheline_aligned_in_smp;
++#endif
++static cpumask_t sched_preempt_mask[SCHED_QUEUE_BITS] ____cacheline_aligned_in_smp;
++static cpumask_t *const sched_idle_mask = &sched_preempt_mask[0];
++
++/* task function */
++static inline const struct cpumask *task_user_cpus(struct task_struct *p)
++{
++ if (!p->user_cpus_ptr)
++ return cpu_possible_mask; /* &init_task.cpus_mask */
++ return p->user_cpus_ptr;
++}
++
++/* sched_queue related functions */
++static inline void sched_queue_init(struct sched_queue *q)
++{
++ int i;
++
++ bitmap_zero(q->bitmap, SCHED_QUEUE_BITS);
++ for(i = 0; i < SCHED_LEVELS; i++)
++ INIT_LIST_HEAD(&q->heads[i]);
++}
++
++/*
++ * Init idle task and put into queue structure of rq
++ * IMPORTANT: may be called multiple times for a single cpu
++ */
++static inline void sched_queue_init_idle(struct sched_queue *q,
++ struct task_struct *idle)
++{
++ idle->sq_idx = IDLE_TASK_SCHED_PRIO;
++ INIT_LIST_HEAD(&q->heads[idle->sq_idx]);
++ list_add(&idle->sq_node, &q->heads[idle->sq_idx]);
++}
++
++static inline void
++clear_recorded_preempt_mask(int pr, int low, int high, int cpu)
++{
++ if (low < pr && pr <= high)
++ cpumask_clear_cpu(cpu, sched_preempt_mask + SCHED_QUEUE_BITS - pr);
++}
++
++static inline void
++set_recorded_preempt_mask(int pr, int low, int high, int cpu)
++{
++ if (low < pr && pr <= high)
++ cpumask_set_cpu(cpu, sched_preempt_mask + SCHED_QUEUE_BITS - pr);
++}
++
++static atomic_t sched_prio_record = ATOMIC_INIT(0);
++
++/* water mark related functions */
++static inline void update_sched_preempt_mask(struct rq *rq)
++{
++ unsigned long prio = find_first_bit(rq->queue.bitmap, SCHED_QUEUE_BITS);
++ unsigned long last_prio = rq->prio;
++ int cpu, pr;
++
++ if (prio == last_prio)
++ return;
++
++ rq->prio = prio;
++ cpu = cpu_of(rq);
++ pr = atomic_read(&sched_prio_record);
++
++ if (prio < last_prio) {
++ if (IDLE_TASK_SCHED_PRIO == last_prio) {
++#ifdef CONFIG_SCHED_SMT
++ if (static_branch_likely(&sched_smt_present))
++ cpumask_andnot(&sched_sg_idle_mask,
++ &sched_sg_idle_mask, cpu_smt_mask(cpu));
++#endif
++ cpumask_clear_cpu(cpu, sched_idle_mask);
++ last_prio -= 2;
++ }
++ clear_recorded_preempt_mask(pr, prio, last_prio, cpu);
++
++ return;
++ }
++ /* last_prio < prio */
++ if (IDLE_TASK_SCHED_PRIO == prio) {
++#ifdef CONFIG_SCHED_SMT
++ if (static_branch_likely(&sched_smt_present) &&
++ cpumask_intersects(cpu_smt_mask(cpu), sched_idle_mask))
++ cpumask_or(&sched_sg_idle_mask,
++ &sched_sg_idle_mask, cpu_smt_mask(cpu));
++#endif
++ cpumask_set_cpu(cpu, sched_idle_mask);
++ prio -= 2;
++ }
++ set_recorded_preempt_mask(pr, last_prio, prio, cpu);
++}
++
++/*
++ * This routine assume that the idle task always in queue
++ */
++static inline struct task_struct *sched_rq_first_task(struct rq *rq)
++{
++ const struct list_head *head = &rq->queue.heads[sched_prio2idx(rq->prio, rq)];
++
++ return list_first_entry(head, struct task_struct, sq_node);
++}
++
++static inline struct task_struct *
++sched_rq_next_task(struct task_struct *p, struct rq *rq)
++{
++ unsigned long idx = p->sq_idx;
++ struct list_head *head = &rq->queue.heads[idx];
++
++ if (list_is_last(&p->sq_node, head)) {
++ idx = find_next_bit(rq->queue.bitmap, SCHED_QUEUE_BITS,
++ sched_idx2prio(idx, rq) + 1);
++ head = &rq->queue.heads[sched_prio2idx(idx, rq)];
++
++ return list_first_entry(head, struct task_struct, sq_node);
++ }
++
++ return list_next_entry(p, sq_node);
++}
++
++static inline struct task_struct *rq_runnable_task(struct rq *rq)
++{
++ struct task_struct *next = sched_rq_first_task(rq);
++
++ if (unlikely(next == rq->skip))
++ next = sched_rq_next_task(next, rq);
++
++ return next;
++}
++
++/*
++ * Serialization rules:
++ *
++ * Lock order:
++ *
++ * p->pi_lock
++ * rq->lock
++ * hrtimer_cpu_base->lock (hrtimer_start() for bandwidth controls)
++ *
++ * rq1->lock
++ * rq2->lock where: rq1 < rq2
++ *
++ * Regular state:
++ *
++ * Normal scheduling state is serialized by rq->lock. __schedule() takes the
++ * local CPU's rq->lock, it optionally removes the task from the runqueue and
++ * always looks at the local rq data structures to find the most eligible task
++ * to run next.
++ *
++ * Task enqueue is also under rq->lock, possibly taken from another CPU.
++ * Wakeups from another LLC domain might use an IPI to transfer the enqueue to
++ * the local CPU to avoid bouncing the runqueue state around [ see
++ * ttwu_queue_wakelist() ]
++ *
++ * Task wakeup, specifically wakeups that involve migration, are horribly
++ * complicated to avoid having to take two rq->locks.
++ *
++ * Special state:
++ *
++ * System-calls and anything external will use task_rq_lock() which acquires
++ * both p->pi_lock and rq->lock. As a consequence the state they change is
++ * stable while holding either lock:
++ *
++ * - sched_setaffinity()/
++ * set_cpus_allowed_ptr(): p->cpus_ptr, p->nr_cpus_allowed
++ * - set_user_nice(): p->se.load, p->*prio
++ * - __sched_setscheduler(): p->sched_class, p->policy, p->*prio,
++ * p->se.load, p->rt_priority,
++ * p->dl.dl_{runtime, deadline, period, flags, bw, density}
++ * - sched_setnuma(): p->numa_preferred_nid
++ * - sched_move_task(): p->sched_task_group
++ * - uclamp_update_active() p->uclamp*
++ *
++ * p->state <- TASK_*:
++ *
++ * is changed locklessly using set_current_state(), __set_current_state() or
++ * set_special_state(), see their respective comments, or by
++ * try_to_wake_up(). This latter uses p->pi_lock to serialize against
++ * concurrent self.
++ *
++ * p->on_rq <- { 0, 1 = TASK_ON_RQ_QUEUED, 2 = TASK_ON_RQ_MIGRATING }:
++ *
++ * is set by activate_task() and cleared by deactivate_task(), under
++ * rq->lock. Non-zero indicates the task is runnable, the special
++ * ON_RQ_MIGRATING state is used for migration without holding both
++ * rq->locks. It indicates task_cpu() is not stable, see task_rq_lock().
++ *
++ * p->on_cpu <- { 0, 1 }:
++ *
++ * is set by prepare_task() and cleared by finish_task() such that it will be
++ * set before p is scheduled-in and cleared after p is scheduled-out, both
++ * under rq->lock. Non-zero indicates the task is running on its CPU.
++ *
++ * [ The astute reader will observe that it is possible for two tasks on one
++ * CPU to have ->on_cpu = 1 at the same time. ]
++ *
++ * task_cpu(p): is changed by set_task_cpu(), the rules are:
++ *
++ * - Don't call set_task_cpu() on a blocked task:
++ *
++ * We don't care what CPU we're not running on, this simplifies hotplug,
++ * the CPU assignment of blocked tasks isn't required to be valid.
++ *
++ * - for try_to_wake_up(), called under p->pi_lock:
++ *
++ * This allows try_to_wake_up() to only take one rq->lock, see its comment.
++ *
++ * - for migration called under rq->lock:
++ * [ see task_on_rq_migrating() in task_rq_lock() ]
++ *
++ * o move_queued_task()
++ * o detach_task()
++ *
++ * - for migration called under double_rq_lock():
++ *
++ * o __migrate_swap_task()
++ * o push_rt_task() / pull_rt_task()
++ * o push_dl_task() / pull_dl_task()
++ * o dl_task_offline_migration()
++ *
++ */
++
++/*
++ * Context: p->pi_lock
++ */
++static inline struct rq
++*__task_access_lock(struct task_struct *p, raw_spinlock_t **plock)
++{
++ struct rq *rq;
++ for (;;) {
++ rq = task_rq(p);
++ if (p->on_cpu || task_on_rq_queued(p)) {
++ raw_spin_lock(&rq->lock);
++ if (likely((p->on_cpu || task_on_rq_queued(p))
++ && rq == task_rq(p))) {
++ *plock = &rq->lock;
++ return rq;
++ }
++ raw_spin_unlock(&rq->lock);
++ } else if (task_on_rq_migrating(p)) {
++ do {
++ cpu_relax();
++ } while (unlikely(task_on_rq_migrating(p)));
++ } else {
++ *plock = NULL;
++ return rq;
++ }
++ }
++}
++
++static inline void
++__task_access_unlock(struct task_struct *p, raw_spinlock_t *lock)
++{
++ if (NULL != lock)
++ raw_spin_unlock(lock);
++}
++
++static inline struct rq
++*task_access_lock_irqsave(struct task_struct *p, raw_spinlock_t **plock,
++ unsigned long *flags)
++{
++ struct rq *rq;
++ for (;;) {
++ rq = task_rq(p);
++ if (p->on_cpu || task_on_rq_queued(p)) {
++ raw_spin_lock_irqsave(&rq->lock, *flags);
++ if (likely((p->on_cpu || task_on_rq_queued(p))
++ && rq == task_rq(p))) {
++ *plock = &rq->lock;
++ return rq;
++ }
++ raw_spin_unlock_irqrestore(&rq->lock, *flags);
++ } else if (task_on_rq_migrating(p)) {
++ do {
++ cpu_relax();
++ } while (unlikely(task_on_rq_migrating(p)));
++ } else {
++ raw_spin_lock_irqsave(&p->pi_lock, *flags);
++ if (likely(!p->on_cpu && !p->on_rq &&
++ rq == task_rq(p))) {
++ *plock = &p->pi_lock;
++ return rq;
++ }
++ raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
++ }
++ }
++}
++
++static inline void
++task_access_unlock_irqrestore(struct task_struct *p, raw_spinlock_t *lock,
++ unsigned long *flags)
++{
++ raw_spin_unlock_irqrestore(lock, *flags);
++}
++
++/*
++ * __task_rq_lock - lock the rq @p resides on.
++ */
++struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++ __acquires(rq->lock)
++{
++ struct rq *rq;
++
++ lockdep_assert_held(&p->pi_lock);
++
++ for (;;) {
++ rq = task_rq(p);
++ raw_spin_lock(&rq->lock);
++ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
++ return rq;
++ raw_spin_unlock(&rq->lock);
++
++ while (unlikely(task_on_rq_migrating(p)))
++ cpu_relax();
++ }
++}
++
++/*
++ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
++ */
++struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++ __acquires(p->pi_lock)
++ __acquires(rq->lock)
++{
++ struct rq *rq;
++
++ for (;;) {
++ raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
++ rq = task_rq(p);
++ raw_spin_lock(&rq->lock);
++ /*
++ * move_queued_task() task_rq_lock()
++ *
++ * ACQUIRE (rq->lock)
++ * [S] ->on_rq = MIGRATING [L] rq = task_rq()
++ * WMB (__set_task_cpu()) ACQUIRE (rq->lock);
++ * [S] ->cpu = new_cpu [L] task_rq()
++ * [L] ->on_rq
++ * RELEASE (rq->lock)
++ *
++ * If we observe the old CPU in task_rq_lock(), the acquire of
++ * the old rq->lock will fully serialize against the stores.
++ *
++ * If we observe the new CPU in task_rq_lock(), the address
++ * dependency headed by '[L] rq = task_rq()' and the acquire
++ * will pair with the WMB to ensure we then also see migrating.
++ */
++ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
++ return rq;
++ }
++ raw_spin_unlock(&rq->lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
++
++ while (unlikely(task_on_rq_migrating(p)))
++ cpu_relax();
++ }
++}
++
++static inline void
++rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
++ __acquires(rq->lock)
++{
++ raw_spin_lock_irqsave(&rq->lock, rf->flags);
++}
++
++static inline void
++rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
++ __releases(rq->lock)
++{
++ raw_spin_unlock_irqrestore(&rq->lock, rf->flags);
++}
++
++DEFINE_LOCK_GUARD_1(rq_lock_irqsave, struct rq,
++ rq_lock_irqsave(_T->lock, &_T->rf),
++ rq_unlock_irqrestore(_T->lock, &_T->rf),
++ struct rq_flags rf)
++
++void raw_spin_rq_lock_nested(struct rq *rq, int subclass)
++{
++ raw_spinlock_t *lock;
++
++ /* Matches synchronize_rcu() in __sched_core_enable() */
++ preempt_disable();
++
++ for (;;) {
++ lock = __rq_lockp(rq);
++ raw_spin_lock_nested(lock, subclass);
++ if (likely(lock == __rq_lockp(rq))) {
++ /* preempt_count *MUST* be > 1 */
++ preempt_enable_no_resched();
++ return;
++ }
++ raw_spin_unlock(lock);
++ }
++}
++
++void raw_spin_rq_unlock(struct rq *rq)
++{
++ raw_spin_unlock(rq_lockp(rq));
++}
++
++/*
++ * RQ-clock updating methods:
++ */
++
++static void update_rq_clock_task(struct rq *rq, s64 delta)
++{
++/*
++ * In theory, the compile should just see 0 here, and optimize out the call
++ * to sched_rt_avg_update. But I don't trust it...
++ */
++ s64 __maybe_unused steal = 0, irq_delta = 0;
++
++#ifdef CONFIG_IRQ_TIME_ACCOUNTING
++ irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
++
++ /*
++ * Since irq_time is only updated on {soft,}irq_exit, we might run into
++ * this case when a previous update_rq_clock() happened inside a
++ * {soft,}irq region.
++ *
++ * When this happens, we stop ->clock_task and only update the
++ * prev_irq_time stamp to account for the part that fit, so that a next
++ * update will consume the rest. This ensures ->clock_task is
++ * monotonic.
++ *
++ * It does however cause some slight miss-attribution of {soft,}irq
++ * time, a more accurate solution would be to update the irq_time using
++ * the current rq->clock timestamp, except that would require using
++ * atomic ops.
++ */
++ if (irq_delta > delta)
++ irq_delta = delta;
++
++ rq->prev_irq_time += irq_delta;
++ delta -= irq_delta;
++ delayacct_irq(rq->curr, irq_delta);
++#endif
++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
++ if (static_key_false((&paravirt_steal_rq_enabled))) {
++ steal = paravirt_steal_clock(cpu_of(rq));
++ steal -= rq->prev_steal_time_rq;
++
++ if (unlikely(steal > delta))
++ steal = delta;
++
++ rq->prev_steal_time_rq += steal;
++ delta -= steal;
++ }
++#endif
++
++ rq->clock_task += delta;
++
++#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
++ if ((irq_delta + steal))
++ update_irq_load_avg(rq, irq_delta + steal);
++#endif
++}
++
++static inline void update_rq_clock(struct rq *rq)
++{
++ s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
++
++ if (unlikely(delta <= 0))
++ return;
++ rq->clock += delta;
++ sched_update_rq_clock(rq);
++ update_rq_clock_task(rq, delta);
++}
++
++/*
++ * RQ Load update routine
++ */
++#define RQ_LOAD_HISTORY_BITS (sizeof(s32) * 8ULL)
++#define RQ_UTIL_SHIFT (8)
++#define RQ_LOAD_HISTORY_TO_UTIL(l) (((l) >> (RQ_LOAD_HISTORY_BITS - 1 - RQ_UTIL_SHIFT)) & 0xff)
++
++#define LOAD_BLOCK(t) ((t) >> 17)
++#define LOAD_HALF_BLOCK(t) ((t) >> 16)
++#define BLOCK_MASK(t) ((t) & ((0x01 << 18) - 1))
++#define LOAD_BLOCK_BIT(b) (1UL << (RQ_LOAD_HISTORY_BITS - 1 - (b)))
++#define CURRENT_LOAD_BIT LOAD_BLOCK_BIT(0)
++
++static inline void rq_load_update(struct rq *rq)
++{
++ u64 time = rq->clock;
++ u64 delta = min(LOAD_BLOCK(time) - LOAD_BLOCK(rq->load_stamp),
++ RQ_LOAD_HISTORY_BITS - 1);
++ u64 prev = !!(rq->load_history & CURRENT_LOAD_BIT);
++ u64 curr = !!rq->nr_running;
++
++ if (delta) {
++ rq->load_history = rq->load_history >> delta;
++
++ if (delta < RQ_UTIL_SHIFT) {
++ rq->load_block += (~BLOCK_MASK(rq->load_stamp)) * prev;
++ if (!!LOAD_HALF_BLOCK(rq->load_block) ^ curr)
++ rq->load_history ^= LOAD_BLOCK_BIT(delta);
++ }
++
++ rq->load_block = BLOCK_MASK(time) * prev;
++ } else {
++ rq->load_block += (time - rq->load_stamp) * prev;
++ }
++ if (prev ^ curr)
++ rq->load_history ^= CURRENT_LOAD_BIT;
++ rq->load_stamp = time;
++}
++
++unsigned long rq_load_util(struct rq *rq, unsigned long max)
++{
++ return RQ_LOAD_HISTORY_TO_UTIL(rq->load_history) * (max >> RQ_UTIL_SHIFT);
++}
++
++#ifdef CONFIG_SMP
++unsigned long sched_cpu_util(int cpu)
++{
++ return rq_load_util(cpu_rq(cpu), arch_scale_cpu_capacity(cpu));
++}
++#endif /* CONFIG_SMP */
++
++#ifdef CONFIG_CPU_FREQ
++/**
++ * cpufreq_update_util - Take a note about CPU utilization changes.
++ * @rq: Runqueue to carry out the update for.
++ * @flags: Update reason flags.
++ *
++ * This function is called by the scheduler on the CPU whose utilization is
++ * being updated.
++ *
++ * It can only be called from RCU-sched read-side critical sections.
++ *
++ * The way cpufreq is currently arranged requires it to evaluate the CPU
++ * performance state (frequency/voltage) on a regular basis to prevent it from
++ * being stuck in a completely inadequate performance level for too long.
++ * That is not guaranteed to happen if the updates are only triggered from CFS
++ * and DL, though, because they may not be coming in if only RT tasks are
++ * active all the time (or there are RT tasks only).
++ *
++ * As a workaround for that issue, this function is called periodically by the
++ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
++ * but that really is a band-aid. Going forward it should be replaced with
++ * solutions targeted more specifically at RT tasks.
++ */
++static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
++{
++ struct update_util_data *data;
++
++#ifdef CONFIG_SMP
++ rq_load_update(rq);
++#endif
++ data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data,
++ cpu_of(rq)));
++ if (data)
++ data->func(data, rq_clock(rq), flags);
++}
++#else
++static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
++{
++#ifdef CONFIG_SMP
++ rq_load_update(rq);
++#endif
++}
++#endif /* CONFIG_CPU_FREQ */
++
++#ifdef CONFIG_NO_HZ_FULL
++/*
++ * Tick may be needed by tasks in the runqueue depending on their policy and
++ * requirements. If tick is needed, lets send the target an IPI to kick it out
++ * of nohz mode if necessary.
++ */
++static inline void sched_update_tick_dependency(struct rq *rq)
++{
++ int cpu = cpu_of(rq);
++
++ if (!tick_nohz_full_cpu(cpu))
++ return;
++
++ if (rq->nr_running < 2)
++ tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
++ else
++ tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
++}
++#else /* !CONFIG_NO_HZ_FULL */
++static inline void sched_update_tick_dependency(struct rq *rq) { }
++#endif
++
++bool sched_task_on_rq(struct task_struct *p)
++{
++ return task_on_rq_queued(p);
++}
++
++unsigned long get_wchan(struct task_struct *p)
++{
++ unsigned long ip = 0;
++ unsigned int state;
++
++ if (!p || p == current)
++ return 0;
++
++ /* Only get wchan if task is blocked and we can keep it that way. */
++ raw_spin_lock_irq(&p->pi_lock);
++ state = READ_ONCE(p->__state);
++ smp_rmb(); /* see try_to_wake_up() */
++ if (state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq)
++ ip = __get_wchan(p);
++ raw_spin_unlock_irq(&p->pi_lock);
++
++ return ip;
++}
++
++/*
++ * Add/Remove/Requeue task to/from the runqueue routines
++ * Context: rq->lock
++ */
++#define __SCHED_DEQUEUE_TASK(p, rq, flags, func) \
++ sched_info_dequeue(rq, p); \
++ \
++ list_del(&p->sq_node); \
++ if (list_empty(&rq->queue.heads[p->sq_idx])) { \
++ clear_bit(sched_idx2prio(p->sq_idx, rq), rq->queue.bitmap); \
++ func; \
++ }
++
++#define __SCHED_ENQUEUE_TASK(p, rq, flags) \
++ sched_info_enqueue(rq, p); \
++ \
++ p->sq_idx = task_sched_prio_idx(p, rq); \
++ list_add_tail(&p->sq_node, &rq->queue.heads[p->sq_idx]); \
++ set_bit(sched_idx2prio(p->sq_idx, rq), rq->queue.bitmap);
++
++static inline void dequeue_task(struct task_struct *p, struct rq *rq, int flags)
++{
++#ifdef ALT_SCHED_DEBUG
++ lockdep_assert_held(&rq->lock);
++
++ /*printk(KERN_INFO "sched: dequeue(%d) %px %016llx\n", cpu_of(rq), p, p->deadline);*/
++ WARN_ONCE(task_rq(p) != rq, "sched: dequeue task reside on cpu%d from cpu%d\n",
++ task_cpu(p), cpu_of(rq));
++#endif
++
++ __SCHED_DEQUEUE_TASK(p, rq, flags, update_sched_preempt_mask(rq));
++ --rq->nr_running;
++#ifdef CONFIG_SMP
++ if (1 == rq->nr_running)
++ cpumask_clear_cpu(cpu_of(rq), &sched_rq_pending_mask);
++#endif
++
++ sched_update_tick_dependency(rq);
++}
++
++static inline void enqueue_task(struct task_struct *p, struct rq *rq, int flags)
++{
++#ifdef ALT_SCHED_DEBUG
++ lockdep_assert_held(&rq->lock);
++
++ /*printk(KERN_INFO "sched: enqueue(%d) %px %d\n", cpu_of(rq), p, p->prio);*/
++ WARN_ONCE(task_rq(p) != rq, "sched: enqueue task reside on cpu%d to cpu%d\n",
++ task_cpu(p), cpu_of(rq));
++#endif
++
++ __SCHED_ENQUEUE_TASK(p, rq, flags);
++ update_sched_preempt_mask(rq);
++ ++rq->nr_running;
++#ifdef CONFIG_SMP
++ if (2 == rq->nr_running)
++ cpumask_set_cpu(cpu_of(rq), &sched_rq_pending_mask);
++#endif
++
++ sched_update_tick_dependency(rq);
++}
++
++static inline void requeue_task(struct task_struct *p, struct rq *rq, int idx)
++{
++#ifdef ALT_SCHED_DEBUG
++ lockdep_assert_held(&rq->lock);
++ /*printk(KERN_INFO "sched: requeue(%d) %px %016llx\n", cpu_of(rq), p, p->deadline);*/
++ WARN_ONCE(task_rq(p) != rq, "sched: cpu[%d] requeue task reside on cpu%d\n",
++ cpu_of(rq), task_cpu(p));
++#endif
++
++ list_del(&p->sq_node);
++ list_add_tail(&p->sq_node, &rq->queue.heads[idx]);
++ if (idx != p->sq_idx) {
++ if (list_empty(&rq->queue.heads[p->sq_idx]))
++ clear_bit(sched_idx2prio(p->sq_idx, rq), rq->queue.bitmap);
++ p->sq_idx = idx;
++ set_bit(sched_idx2prio(p->sq_idx, rq), rq->queue.bitmap);
++ update_sched_preempt_mask(rq);
++ }
++}
++
++/*
++ * cmpxchg based fetch_or, macro so it works for different integer types
++ */
++#define fetch_or(ptr, mask) \
++ ({ \
++ typeof(ptr) _ptr = (ptr); \
++ typeof(mask) _mask = (mask); \
++ typeof(*_ptr) _val = *_ptr; \
++ \
++ do { \
++ } while (!try_cmpxchg(_ptr, &_val, _val | _mask)); \
++ _val; \
++})
++
++#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
++/*
++ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
++ * this avoids any races wrt polling state changes and thereby avoids
++ * spurious IPIs.
++ */
++static inline bool set_nr_and_not_polling(struct task_struct *p)
++{
++ struct thread_info *ti = task_thread_info(p);
++ return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
++}
++
++/*
++ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
++ *
++ * If this returns true, then the idle task promises to call
++ * sched_ttwu_pending() and reschedule soon.
++ */
++static bool set_nr_if_polling(struct task_struct *p)
++{
++ struct thread_info *ti = task_thread_info(p);
++ typeof(ti->flags) val = READ_ONCE(ti->flags);
++
++ do {
++ if (!(val & _TIF_POLLING_NRFLAG))
++ return false;
++ if (val & _TIF_NEED_RESCHED)
++ return true;
++ } while (!try_cmpxchg(&ti->flags, &val, val | _TIF_NEED_RESCHED));
++
++ return true;
++}
++
++#else
++static inline bool set_nr_and_not_polling(struct task_struct *p)
++{
++ set_tsk_need_resched(p);
++ return true;
++}
++
++#ifdef CONFIG_SMP
++static inline bool set_nr_if_polling(struct task_struct *p)
++{
++ return false;
++}
++#endif
++#endif
++
++static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
++{
++ struct wake_q_node *node = &task->wake_q;
++
++ /*
++ * Atomically grab the task, if ->wake_q is !nil already it means
++ * it's already queued (either by us or someone else) and will get the
++ * wakeup due to that.
++ *
++ * In order to ensure that a pending wakeup will observe our pending
++ * state, even in the failed case, an explicit smp_mb() must be used.
++ */
++ smp_mb__before_atomic();
++ if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
++ return false;
++
++ /*
++ * The head is context local, there can be no concurrency.
++ */
++ *head->lastp = node;
++ head->lastp = &node->next;
++ return true;
++}
++
++/**
++ * wake_q_add() - queue a wakeup for 'later' waking.
++ * @head: the wake_q_head to add @task to
++ * @task: the task to queue for 'later' wakeup
++ *
++ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
++ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
++ * instantly.
++ *
++ * This function must be used as-if it were wake_up_process(); IOW the task
++ * must be ready to be woken at this location.
++ */
++void wake_q_add(struct wake_q_head *head, struct task_struct *task)
++{
++ if (__wake_q_add(head, task))
++ get_task_struct(task);
++}
++
++/**
++ * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
++ * @head: the wake_q_head to add @task to
++ * @task: the task to queue for 'later' wakeup
++ *
++ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
++ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
++ * instantly.
++ *
++ * This function must be used as-if it were wake_up_process(); IOW the task
++ * must be ready to be woken at this location.
++ *
++ * This function is essentially a task-safe equivalent to wake_q_add(). Callers
++ * that already hold reference to @task can call the 'safe' version and trust
++ * wake_q to do the right thing depending whether or not the @task is already
++ * queued for wakeup.
++ */
++void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
++{
++ if (!__wake_q_add(head, task))
++ put_task_struct(task);
++}
++
++void wake_up_q(struct wake_q_head *head)
++{
++ struct wake_q_node *node = head->first;
++
++ while (node != WAKE_Q_TAIL) {
++ struct task_struct *task;
++
++ task = container_of(node, struct task_struct, wake_q);
++ /* task can safely be re-inserted now: */
++ node = node->next;
++ task->wake_q.next = NULL;
++
++ /*
++ * wake_up_process() executes a full barrier, which pairs with
++ * the queueing in wake_q_add() so as not to miss wakeups.
++ */
++ wake_up_process(task);
++ put_task_struct(task);
++ }
++}
++
++/*
++ * resched_curr - mark rq's current task 'to be rescheduled now'.
++ *
++ * On UP this means the setting of the need_resched flag, on SMP it
++ * might also involve a cross-CPU call to trigger the scheduler on
++ * the target CPU.
++ */
++void resched_curr(struct rq *rq)
++{
++ struct task_struct *curr = rq->curr;
++ int cpu;
++
++ lockdep_assert_held(&rq->lock);
++
++ if (test_tsk_need_resched(curr))
++ return;
++
++ cpu = cpu_of(rq);
++ if (cpu == smp_processor_id()) {
++ set_tsk_need_resched(curr);
++ set_preempt_need_resched();
++ return;
++ }
++
++ if (set_nr_and_not_polling(curr))
++ smp_send_reschedule(cpu);
++ else
++ trace_sched_wake_idle_without_ipi(cpu);
++}
++
++void resched_cpu(int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++ unsigned long flags;
++
++ raw_spin_lock_irqsave(&rq->lock, flags);
++ if (cpu_online(cpu) || cpu == smp_processor_id())
++ resched_curr(cpu_rq(cpu));
++ raw_spin_unlock_irqrestore(&rq->lock, flags);
++}
++
++#ifdef CONFIG_SMP
++#ifdef CONFIG_NO_HZ_COMMON
++void nohz_balance_enter_idle(int cpu) {}
++
++void select_nohz_load_balancer(int stop_tick) {}
++
++void set_cpu_sd_state_idle(void) {}
++
++/*
++ * In the semi idle case, use the nearest busy CPU for migrating timers
++ * from an idle CPU. This is good for power-savings.
++ *
++ * We don't do similar optimization for completely idle system, as
++ * selecting an idle CPU will add more delays to the timers than intended
++ * (as that CPU's timer base may not be uptodate wrt jiffies etc).
++ */
++int get_nohz_timer_target(void)
++{
++ int i, cpu = smp_processor_id(), default_cpu = -1;
++ struct cpumask *mask;
++ const struct cpumask *hk_mask;
++
++ if (housekeeping_cpu(cpu, HK_TYPE_TIMER)) {
++ if (!idle_cpu(cpu))
++ return cpu;
++ default_cpu = cpu;
++ }
++
++ hk_mask = housekeeping_cpumask(HK_TYPE_TIMER);
++
++ for (mask = per_cpu(sched_cpu_topo_masks, cpu) + 1;
++ mask < per_cpu(sched_cpu_topo_end_mask, cpu); mask++)
++ for_each_cpu_and(i, mask, hk_mask)
++ if (!idle_cpu(i))
++ return i;
++
++ if (default_cpu == -1)
++ default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
++ cpu = default_cpu;
++
++ return cpu;
++}
++
++/*
++ * When add_timer_on() enqueues a timer into the timer wheel of an
++ * idle CPU then this timer might expire before the next timer event
++ * which is scheduled to wake up that CPU. In case of a completely
++ * idle system the next event might even be infinite time into the
++ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
++ * leaves the inner idle loop so the newly added timer is taken into
++ * account when the CPU goes back to idle and evaluates the timer
++ * wheel for the next timer event.
++ */
++static inline void wake_up_idle_cpu(int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++
++ if (cpu == smp_processor_id())
++ return;
++
++ if (set_nr_and_not_polling(rq->idle))
++ smp_send_reschedule(cpu);
++ else
++ trace_sched_wake_idle_without_ipi(cpu);
++}
++
++static inline bool wake_up_full_nohz_cpu(int cpu)
++{
++ /*
++ * We just need the target to call irq_exit() and re-evaluate
++ * the next tick. The nohz full kick at least implies that.
++ * If needed we can still optimize that later with an
++ * empty IRQ.
++ */
++ if (cpu_is_offline(cpu))
++ return true; /* Don't try to wake offline CPUs. */
++ if (tick_nohz_full_cpu(cpu)) {
++ if (cpu != smp_processor_id() ||
++ tick_nohz_tick_stopped())
++ tick_nohz_full_kick_cpu(cpu);
++ return true;
++ }
++
++ return false;
++}
++
++void wake_up_nohz_cpu(int cpu)
++{
++ if (!wake_up_full_nohz_cpu(cpu))
++ wake_up_idle_cpu(cpu);
++}
++
++static void nohz_csd_func(void *info)
++{
++ struct rq *rq = info;
++ int cpu = cpu_of(rq);
++ unsigned int flags;
++
++ /*
++ * Release the rq::nohz_csd.
++ */
++ flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(cpu));
++ WARN_ON(!(flags & NOHZ_KICK_MASK));
++
++ rq->idle_balance = idle_cpu(cpu);
++ if (rq->idle_balance && !need_resched()) {
++ rq->nohz_idle_balance = flags;
++ raise_softirq_irqoff(SCHED_SOFTIRQ);
++ }
++}
++
++#endif /* CONFIG_NO_HZ_COMMON */
++#endif /* CONFIG_SMP */
++
++static inline void wakeup_preempt(struct rq *rq)
++{
++ if (sched_rq_first_task(rq) != rq->curr)
++ resched_curr(rq);
++}
++
++static __always_inline
++int __task_state_match(struct task_struct *p, unsigned int state)
++{
++ if (READ_ONCE(p->__state) & state)
++ return 1;
++
++ if (READ_ONCE(p->saved_state) & state)
++ return -1;
++
++ return 0;
++}
++
++static __always_inline
++int task_state_match(struct task_struct *p, unsigned int state)
++{
++ /*
++ * Serialize against current_save_and_set_rtlock_wait_state(),
++ * current_restore_rtlock_saved_state(), and __refrigerator().
++ */
++ guard(raw_spinlock_irq)(&p->pi_lock);
++
++ return __task_state_match(p, state);
++}
++
++/*
++ * wait_task_inactive - wait for a thread to unschedule.
++ *
++ * Wait for the thread to block in any of the states set in @match_state.
++ * If it changes, i.e. @p might have woken up, then return zero. When we
++ * succeed in waiting for @p to be off its CPU, we return a positive number
++ * (its total switch count). If a second call a short while later returns the
++ * same number, the caller can be sure that @p has remained unscheduled the
++ * whole time.
++ *
++ * The caller must ensure that the task *will* unschedule sometime soon,
++ * else this function might spin for a *long* time. This function can't
++ * be called with interrupts off, or it may introduce deadlock with
++ * smp_call_function() if an IPI is sent by the same process we are
++ * waiting to become inactive.
++ */
++unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
++{
++ unsigned long flags;
++ int running, queued, match;
++ unsigned long ncsw;
++ struct rq *rq;
++ raw_spinlock_t *lock;
++
++ for (;;) {
++ rq = task_rq(p);
++
++ /*
++ * If the task is actively running on another CPU
++ * still, just relax and busy-wait without holding
++ * any locks.
++ *
++ * NOTE! Since we don't hold any locks, it's not
++ * even sure that "rq" stays as the right runqueue!
++ * But we don't care, since this will return false
++ * if the runqueue has changed and p is actually now
++ * running somewhere else!
++ */
++ while (task_on_cpu(p)) {
++ if (!task_state_match(p, match_state))
++ return 0;
++ cpu_relax();
++ }
++
++ /*
++ * Ok, time to look more closely! We need the rq
++ * lock now, to be *sure*. If we're wrong, we'll
++ * just go back and repeat.
++ */
++ task_access_lock_irqsave(p, &lock, &flags);
++ trace_sched_wait_task(p);
++ running = task_on_cpu(p);
++ queued = p->on_rq;
++ ncsw = 0;
++ if ((match = __task_state_match(p, match_state))) {
++ /*
++ * When matching on p->saved_state, consider this task
++ * still queued so it will wait.
++ */
++ if (match < 0)
++ queued = 1;
++ ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
++ }
++ task_access_unlock_irqrestore(p, lock, &flags);
++
++ /*
++ * If it changed from the expected state, bail out now.
++ */
++ if (unlikely(!ncsw))
++ break;
++
++ /*
++ * Was it really running after all now that we
++ * checked with the proper locks actually held?
++ *
++ * Oops. Go back and try again..
++ */
++ if (unlikely(running)) {
++ cpu_relax();
++ continue;
++ }
++
++ /*
++ * It's not enough that it's not actively running,
++ * it must be off the runqueue _entirely_, and not
++ * preempted!
++ *
++ * So if it was still runnable (but just not actively
++ * running right now), it's preempted, and we should
++ * yield - it could be a while.
++ */
++ if (unlikely(queued)) {
++ ktime_t to = NSEC_PER_SEC / HZ;
++
++ set_current_state(TASK_UNINTERRUPTIBLE);
++ schedule_hrtimeout(&to, HRTIMER_MODE_REL_HARD);
++ continue;
++ }
++
++ /*
++ * Ahh, all good. It wasn't running, and it wasn't
++ * runnable, which means that it will never become
++ * running in the future either. We're all done!
++ */
++ break;
++ }
++
++ return ncsw;
++}
++
++#ifdef CONFIG_SCHED_HRTICK
++/*
++ * Use HR-timers to deliver accurate preemption points.
++ */
++
++static void hrtick_clear(struct rq *rq)
++{
++ if (hrtimer_active(&rq->hrtick_timer))
++ hrtimer_cancel(&rq->hrtick_timer);
++}
++
++/*
++ * High-resolution timer tick.
++ * Runs from hardirq context with interrupts disabled.
++ */
++static enum hrtimer_restart hrtick(struct hrtimer *timer)
++{
++ struct rq *rq = container_of(timer, struct rq, hrtick_timer);
++
++ WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
++
++ raw_spin_lock(&rq->lock);
++ resched_curr(rq);
++ raw_spin_unlock(&rq->lock);
++
++ return HRTIMER_NORESTART;
++}
++
++/*
++ * Use hrtick when:
++ * - enabled by features
++ * - hrtimer is actually high res
++ */
++static inline int hrtick_enabled(struct rq *rq)
++{
++ /**
++ * Alt schedule FW doesn't support sched_feat yet
++ if (!sched_feat(HRTICK))
++ return 0;
++ */
++ if (!cpu_active(cpu_of(rq)))
++ return 0;
++ return hrtimer_is_hres_active(&rq->hrtick_timer);
++}
++
++#ifdef CONFIG_SMP
++
++static void __hrtick_restart(struct rq *rq)
++{
++ struct hrtimer *timer = &rq->hrtick_timer;
++ ktime_t time = rq->hrtick_time;
++
++ hrtimer_start(timer, time, HRTIMER_MODE_ABS_PINNED_HARD);
++}
++
++/*
++ * called from hardirq (IPI) context
++ */
++static void __hrtick_start(void *arg)
++{
++ struct rq *rq = arg;
++
++ raw_spin_lock(&rq->lock);
++ __hrtick_restart(rq);
++ raw_spin_unlock(&rq->lock);
++}
++
++/*
++ * Called to set the hrtick timer state.
++ *
++ * called with rq->lock held and irqs disabled
++ */
++void hrtick_start(struct rq *rq, u64 delay)
++{
++ struct hrtimer *timer = &rq->hrtick_timer;
++ s64 delta;
++
++ /*
++ * Don't schedule slices shorter than 10000ns, that just
++ * doesn't make sense and can cause timer DoS.
++ */
++ delta = max_t(s64, delay, 10000LL);
++
++ rq->hrtick_time = ktime_add_ns(timer->base->get_time(), delta);
++
++ if (rq == this_rq())
++ __hrtick_restart(rq);
++ else
++ smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
++}
++
++#else
++/*
++ * Called to set the hrtick timer state.
++ *
++ * called with rq->lock held and irqs disabled
++ */
++void hrtick_start(struct rq *rq, u64 delay)
++{
++ /*
++ * Don't schedule slices shorter than 10000ns, that just
++ * doesn't make sense. Rely on vruntime for fairness.
++ */
++ delay = max_t(u64, delay, 10000LL);
++ hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
++ HRTIMER_MODE_REL_PINNED_HARD);
++}
++#endif /* CONFIG_SMP */
++
++static void hrtick_rq_init(struct rq *rq)
++{
++#ifdef CONFIG_SMP
++ INIT_CSD(&rq->hrtick_csd, __hrtick_start, rq);
++#endif
++
++ hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
++ rq->hrtick_timer.function = hrtick;
++}
++#else /* CONFIG_SCHED_HRTICK */
++static inline int hrtick_enabled(struct rq *rq)
++{
++ return 0;
++}
++
++static inline void hrtick_clear(struct rq *rq)
++{
++}
++
++static inline void hrtick_rq_init(struct rq *rq)
++{
++}
++#endif /* CONFIG_SCHED_HRTICK */
++
++static inline int __normal_prio(int policy, int rt_prio, int static_prio)
++{
++ return rt_policy(policy) ? (MAX_RT_PRIO - 1 - rt_prio) :
++ static_prio + MAX_PRIORITY_ADJ;
++}
++
++/*
++ * Calculate the expected normal priority: i.e. priority
++ * without taking RT-inheritance into account. Might be
++ * boosted by interactivity modifiers. Changes upon fork,
++ * setprio syscalls, and whenever the interactivity
++ * estimator recalculates.
++ */
++static inline int normal_prio(struct task_struct *p)
++{
++ return __normal_prio(p->policy, p->rt_priority, p->static_prio);
++}
++
++/*
++ * Calculate the current priority, i.e. the priority
++ * taken into account by the scheduler. This value might
++ * be boosted by RT tasks as it will be RT if the task got
++ * RT-boosted. If not then it returns p->normal_prio.
++ */
++static int effective_prio(struct task_struct *p)
++{
++ p->normal_prio = normal_prio(p);
++ /*
++ * If we are RT tasks or we were boosted to RT priority,
++ * keep the priority unchanged. Otherwise, update priority
++ * to the normal priority:
++ */
++ if (!rt_prio(p->prio))
++ return p->normal_prio;
++ return p->prio;
++}
++
++/*
++ * activate_task - move a task to the runqueue.
++ *
++ * Context: rq->lock
++ */
++static void activate_task(struct task_struct *p, struct rq *rq)
++{
++ enqueue_task(p, rq, ENQUEUE_WAKEUP);
++ p->on_rq = TASK_ON_RQ_QUEUED;
++
++ /*
++ * If in_iowait is set, the code below may not trigger any cpufreq
++ * utilization updates, so do it here explicitly with the IOWAIT flag
++ * passed.
++ */
++ cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT * p->in_iowait);
++}
++
++/*
++ * deactivate_task - remove a task from the runqueue.
++ *
++ * Context: rq->lock
++ */
++static inline void deactivate_task(struct task_struct *p, struct rq *rq)
++{
++ dequeue_task(p, rq, DEQUEUE_SLEEP);
++ p->on_rq = 0;
++ cpufreq_update_util(rq, 0);
++}
++
++static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
++{
++#ifdef CONFIG_SMP
++ /*
++ * After ->cpu is set up to a new value, task_access_lock(p, ...) can be
++ * successfully executed on another CPU. We must ensure that updates of
++ * per-task data have been completed by this moment.
++ */
++ smp_wmb();
++
++ WRITE_ONCE(task_thread_info(p)->cpu, cpu);
++#endif
++}
++
++static inline bool is_migration_disabled(struct task_struct *p)
++{
++#ifdef CONFIG_SMP
++ return p->migration_disabled;
++#else
++ return false;
++#endif
++}
++
++#define SCA_CHECK 0x01
++#define SCA_USER 0x08
++
++#ifdef CONFIG_SMP
++
++void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
++{
++#ifdef CONFIG_SCHED_DEBUG
++ unsigned int state = READ_ONCE(p->__state);
++
++ /*
++ * We should never call set_task_cpu() on a blocked task,
++ * ttwu() will sort out the placement.
++ */
++ WARN_ON_ONCE(state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq);
++
++#ifdef CONFIG_LOCKDEP
++ /*
++ * The caller should hold either p->pi_lock or rq->lock, when changing
++ * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
++ *
++ * sched_move_task() holds both and thus holding either pins the cgroup,
++ * see task_group().
++ */
++ WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
++ lockdep_is_held(&task_rq(p)->lock)));
++#endif
++ /*
++ * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
++ */
++ WARN_ON_ONCE(!cpu_online(new_cpu));
++
++ WARN_ON_ONCE(is_migration_disabled(p));
++#endif
++ trace_sched_migrate_task(p, new_cpu);
++
++ if (task_cpu(p) != new_cpu)
++ {
++ rseq_migrate(p);
++ perf_event_task_migrate(p);
++ }
++
++ __set_task_cpu(p, new_cpu);
++}
++
++#define MDF_FORCE_ENABLED 0x80
++
++static void
++__do_set_cpus_ptr(struct task_struct *p, const struct cpumask *new_mask)
++{
++ /*
++ * This here violates the locking rules for affinity, since we're only
++ * supposed to change these variables while holding both rq->lock and
++ * p->pi_lock.
++ *
++ * HOWEVER, it magically works, because ttwu() is the only code that
++ * accesses these variables under p->pi_lock and only does so after
++ * smp_cond_load_acquire(&p->on_cpu, !VAL), and we're in __schedule()
++ * before finish_task().
++ *
++ * XXX do further audits, this smells like something putrid.
++ */
++ SCHED_WARN_ON(!p->on_cpu);
++ p->cpus_ptr = new_mask;
++}
++
++void migrate_disable(void)
++{
++ struct task_struct *p = current;
++ int cpu;
++
++ if (p->migration_disabled) {
++ p->migration_disabled++;
++ return;
++ }
++
++ guard(preempt)();
++ cpu = smp_processor_id();
++ if (cpumask_test_cpu(cpu, &p->cpus_mask)) {
++ cpu_rq(cpu)->nr_pinned++;
++ p->migration_disabled = 1;
++ p->migration_flags &= ~MDF_FORCE_ENABLED;
++
++ /*
++ * Violates locking rules! see comment in __do_set_cpus_ptr().
++ */
++ if (p->cpus_ptr == &p->cpus_mask)
++ __do_set_cpus_ptr(p, cpumask_of(cpu));
++ }
++}
++EXPORT_SYMBOL_GPL(migrate_disable);
++
++void migrate_enable(void)
++{
++ struct task_struct *p = current;
++
++ if (0 == p->migration_disabled)
++ return;
++
++ if (p->migration_disabled > 1) {
++ p->migration_disabled--;
++ return;
++ }
++
++ if (WARN_ON_ONCE(!p->migration_disabled))
++ return;
++
++ /*
++ * Ensure stop_task runs either before or after this, and that
++ * __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule().
++ */
++ guard(preempt)();
++ /*
++ * Assumption: current should be running on allowed cpu
++ */
++ WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &p->cpus_mask));
++ if (p->cpus_ptr != &p->cpus_mask)
++ __do_set_cpus_ptr(p, &p->cpus_mask);
++ /*
++ * Mustn't clear migration_disabled() until cpus_ptr points back at the
++ * regular cpus_mask, otherwise things that race (eg.
++ * select_fallback_rq) get confused.
++ */
++ barrier();
++ p->migration_disabled = 0;
++ this_rq()->nr_pinned--;
++}
++EXPORT_SYMBOL_GPL(migrate_enable);
++
++static inline bool rq_has_pinned_tasks(struct rq *rq)
++{
++ return rq->nr_pinned;
++}
++
++/*
++ * Per-CPU kthreads are allowed to run on !active && online CPUs, see
++ * __set_cpus_allowed_ptr() and select_fallback_rq().
++ */
++static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
++{
++ /* When not in the task's cpumask, no point in looking further. */
++ if (!cpumask_test_cpu(cpu, p->cpus_ptr))
++ return false;
++
++ /* migrate_disabled() must be allowed to finish. */
++ if (is_migration_disabled(p))
++ return cpu_online(cpu);
++
++ /* Non kernel threads are not allowed during either online or offline. */
++ if (!(p->flags & PF_KTHREAD))
++ return cpu_active(cpu) && task_cpu_possible(cpu, p);
++
++ /* KTHREAD_IS_PER_CPU is always allowed. */
++ if (kthread_is_per_cpu(p))
++ return cpu_online(cpu);
++
++ /* Regular kernel threads don't get to stay during offline. */
++ if (cpu_dying(cpu))
++ return false;
++
++ /* But are allowed during online. */
++ return cpu_online(cpu);
++}
++
++/*
++ * This is how migration works:
++ *
++ * 1) we invoke migration_cpu_stop() on the target CPU using
++ * stop_one_cpu().
++ * 2) stopper starts to run (implicitly forcing the migrated thread
++ * off the CPU)
++ * 3) it checks whether the migrated task is still in the wrong runqueue.
++ * 4) if it's in the wrong runqueue then the migration thread removes
++ * it and puts it into the right queue.
++ * 5) stopper completes and stop_one_cpu() returns and the migration
++ * is done.
++ */
++
++/*
++ * move_queued_task - move a queued task to new rq.
++ *
++ * Returns (locked) new rq. Old rq's lock is released.
++ */
++static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int
++ new_cpu)
++{
++ int src_cpu;
++
++ lockdep_assert_held(&rq->lock);
++
++ src_cpu = cpu_of(rq);
++ WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
++ dequeue_task(p, rq, 0);
++ set_task_cpu(p, new_cpu);
++ raw_spin_unlock(&rq->lock);
++
++ rq = cpu_rq(new_cpu);
++
++ raw_spin_lock(&rq->lock);
++ WARN_ON_ONCE(task_cpu(p) != new_cpu);
++
++ sched_mm_cid_migrate_to(rq, p, src_cpu);
++
++ sched_task_sanity_check(p, rq);
++ enqueue_task(p, rq, 0);
++ p->on_rq = TASK_ON_RQ_QUEUED;
++ wakeup_preempt(rq);
++
++ return rq;
++}
++
++struct migration_arg {
++ struct task_struct *task;
++ int dest_cpu;
++};
++
++/*
++ * Move (not current) task off this CPU, onto the destination CPU. We're doing
++ * this because either it can't run here any more (set_cpus_allowed()
++ * away from this CPU, or CPU going down), or because we're
++ * attempting to rebalance this task on exec (sched_exec).
++ *
++ * So we race with normal scheduler movements, but that's OK, as long
++ * as the task is no longer on this CPU.
++ */
++static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int
++ dest_cpu)
++{
++ /* Affinity changed (again). */
++ if (!is_cpu_allowed(p, dest_cpu))
++ return rq;
++
++ return move_queued_task(rq, p, dest_cpu);
++}
++
++/*
++ * migration_cpu_stop - this will be executed by a highprio stopper thread
++ * and performs thread migration by bumping thread off CPU then
++ * 'pushing' onto another runqueue.
++ */
++static int migration_cpu_stop(void *data)
++{
++ struct migration_arg *arg = data;
++ struct task_struct *p = arg->task;
++ struct rq *rq = this_rq();
++ unsigned long flags;
++
++ /*
++ * The original target CPU might have gone down and we might
++ * be on another CPU but it doesn't matter.
++ */
++ local_irq_save(flags);
++ /*
++ * We need to explicitly wake pending tasks before running
++ * __migrate_task() such that we will not miss enforcing cpus_ptr
++ * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
++ */
++ flush_smp_call_function_queue();
++
++ raw_spin_lock(&p->pi_lock);
++ raw_spin_lock(&rq->lock);
++ /*
++ * If task_rq(p) != rq, it cannot be migrated here, because we're
++ * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
++ * we're holding p->pi_lock.
++ */
++ if (task_rq(p) == rq && task_on_rq_queued(p)) {
++ update_rq_clock(rq);
++ rq = __migrate_task(rq, p, arg->dest_cpu);
++ }
++ raw_spin_unlock(&rq->lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++
++ return 0;
++}
++
++static inline void
++set_cpus_allowed_common(struct task_struct *p, struct affinity_context *ctx)
++{
++ cpumask_copy(&p->cpus_mask, ctx->new_mask);
++ p->nr_cpus_allowed = cpumask_weight(ctx->new_mask);
++
++ /*
++ * Swap in a new user_cpus_ptr if SCA_USER flag set
++ */
++ if (ctx->flags & SCA_USER)
++ swap(p->user_cpus_ptr, ctx->user_mask);
++}
++
++static void
++__do_set_cpus_allowed(struct task_struct *p, struct affinity_context *ctx)
++{
++ lockdep_assert_held(&p->pi_lock);
++ set_cpus_allowed_common(p, ctx);
++}
++
++/*
++ * Used for kthread_bind() and select_fallback_rq(), in both cases the user
++ * affinity (if any) should be destroyed too.
++ */
++void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
++{
++ struct affinity_context ac = {
++ .new_mask = new_mask,
++ .user_mask = NULL,
++ .flags = SCA_USER, /* clear the user requested mask */
++ };
++ union cpumask_rcuhead {
++ cpumask_t cpumask;
++ struct rcu_head rcu;
++ };
++
++ __do_set_cpus_allowed(p, &ac);
++
++ /*
++ * Because this is called with p->pi_lock held, it is not possible
++ * to use kfree() here (when PREEMPT_RT=y), therefore punt to using
++ * kfree_rcu().
++ */
++ kfree_rcu((union cpumask_rcuhead *)ac.user_mask, rcu);
++}
++
++static cpumask_t *alloc_user_cpus_ptr(int node)
++{
++ /*
++ * See do_set_cpus_allowed() above for the rcu_head usage.
++ */
++ int size = max_t(int, cpumask_size(), sizeof(struct rcu_head));
++
++ return kmalloc_node(size, GFP_KERNEL, node);
++}
++
++int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src,
++ int node)
++{
++ cpumask_t *user_mask;
++ unsigned long flags;
++
++ /*
++ * Always clear dst->user_cpus_ptr first as their user_cpus_ptr's
++ * may differ by now due to racing.
++ */
++ dst->user_cpus_ptr = NULL;
++
++ /*
++ * This check is racy and losing the race is a valid situation.
++ * It is not worth the extra overhead of taking the pi_lock on
++ * every fork/clone.
++ */
++ if (data_race(!src->user_cpus_ptr))
++ return 0;
++
++ user_mask = alloc_user_cpus_ptr(node);
++ if (!user_mask)
++ return -ENOMEM;
++
++ /*
++ * Use pi_lock to protect content of user_cpus_ptr
++ *
++ * Though unlikely, user_cpus_ptr can be reset to NULL by a concurrent
++ * do_set_cpus_allowed().
++ */
++ raw_spin_lock_irqsave(&src->pi_lock, flags);
++ if (src->user_cpus_ptr) {
++ swap(dst->user_cpus_ptr, user_mask);
++ cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr);
++ }
++ raw_spin_unlock_irqrestore(&src->pi_lock, flags);
++
++ if (unlikely(user_mask))
++ kfree(user_mask);
++
++ return 0;
++}
++
++static inline struct cpumask *clear_user_cpus_ptr(struct task_struct *p)
++{
++ struct cpumask *user_mask = NULL;
++
++ swap(p->user_cpus_ptr, user_mask);
++
++ return user_mask;
++}
++
++void release_user_cpus_ptr(struct task_struct *p)
++{
++ kfree(clear_user_cpus_ptr(p));
++}
++
++#endif
++
++/**
++ * task_curr - is this task currently executing on a CPU?
++ * @p: the task in question.
++ *
++ * Return: 1 if the task is currently executing. 0 otherwise.
++ */
++inline int task_curr(const struct task_struct *p)
++{
++ return cpu_curr(task_cpu(p)) == p;
++}
++
++#ifdef CONFIG_SMP
++/***
++ * kick_process - kick a running thread to enter/exit the kernel
++ * @p: the to-be-kicked thread
++ *
++ * Cause a process which is running on another CPU to enter
++ * kernel-mode, without any delay. (to get signals handled.)
++ *
++ * NOTE: this function doesn't have to take the runqueue lock,
++ * because all it wants to ensure is that the remote task enters
++ * the kernel. If the IPI races and the task has been migrated
++ * to another CPU then no harm is done and the purpose has been
++ * achieved as well.
++ */
++void kick_process(struct task_struct *p)
++{
++ guard(preempt)();
++ int cpu = task_cpu(p);
++
++ if ((cpu != smp_processor_id()) && task_curr(p))
++ smp_send_reschedule(cpu);
++}
++EXPORT_SYMBOL_GPL(kick_process);
++
++/*
++ * ->cpus_ptr is protected by both rq->lock and p->pi_lock
++ *
++ * A few notes on cpu_active vs cpu_online:
++ *
++ * - cpu_active must be a subset of cpu_online
++ *
++ * - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
++ * see __set_cpus_allowed_ptr(). At this point the newly online
++ * CPU isn't yet part of the sched domains, and balancing will not
++ * see it.
++ *
++ * - on cpu-down we clear cpu_active() to mask the sched domains and
++ * avoid the load balancer to place new tasks on the to be removed
++ * CPU. Existing tasks will remain running there and will be taken
++ * off.
++ *
++ * This means that fallback selection must not select !active CPUs.
++ * And can assume that any active CPU must be online. Conversely
++ * select_task_rq() below may allow selection of !active CPUs in order
++ * to satisfy the above rules.
++ */
++static int select_fallback_rq(int cpu, struct task_struct *p)
++{
++ int nid = cpu_to_node(cpu);
++ const struct cpumask *nodemask = NULL;
++ enum { cpuset, possible, fail } state = cpuset;
++ int dest_cpu;
++
++ /*
++ * If the node that the CPU is on has been offlined, cpu_to_node()
++ * will return -1. There is no CPU on the node, and we should
++ * select the CPU on the other node.
++ */
++ if (nid != -1) {
++ nodemask = cpumask_of_node(nid);
++
++ /* Look for allowed, online CPU in same node. */
++ for_each_cpu(dest_cpu, nodemask) {
++ if (is_cpu_allowed(p, dest_cpu))
++ return dest_cpu;
++ }
++ }
++
++ for (;;) {
++ /* Any allowed, online CPU? */
++ for_each_cpu(dest_cpu, p->cpus_ptr) {
++ if (!is_cpu_allowed(p, dest_cpu))
++ continue;
++ goto out;
++ }
++
++ /* No more Mr. Nice Guy. */
++ switch (state) {
++ case cpuset:
++ if (cpuset_cpus_allowed_fallback(p)) {
++ state = possible;
++ break;
++ }
++ fallthrough;
++ case possible:
++ /*
++ * XXX When called from select_task_rq() we only
++ * hold p->pi_lock and again violate locking order.
++ *
++ * More yuck to audit.
++ */
++ do_set_cpus_allowed(p, task_cpu_possible_mask(p));
++ state = fail;
++ break;
++
++ case fail:
++ BUG();
++ break;
++ }
++ }
++
++out:
++ if (state != cpuset) {
++ /*
++ * Don't tell them about moving exiting tasks or
++ * kernel threads (both mm NULL), since they never
++ * leave kernel.
++ */
++ if (p->mm && printk_ratelimit()) {
++ printk_deferred("process %d (%s) no longer affine to cpu%d\n",
++ task_pid_nr(p), p->comm, cpu);
++ }
++ }
++
++ return dest_cpu;
++}
++
++static inline void
++sched_preempt_mask_flush(cpumask_t *mask, int prio)
++{
++ int cpu;
++
++ cpumask_copy(mask, sched_idle_mask);
++
++ for_each_clear_bit(cpu, cpumask_bits(mask), nr_cpumask_bits) {
++ if (prio < cpu_rq(cpu)->prio)
++ cpumask_set_cpu(cpu, mask);
++ }
++}
++
++static inline int
++preempt_mask_check(struct task_struct *p, cpumask_t *allow_mask, cpumask_t *preempt_mask)
++{
++ int task_prio = task_sched_prio(p);
++ cpumask_t *mask = sched_preempt_mask + SCHED_QUEUE_BITS - 1 - task_prio;
++ int pr = atomic_read(&sched_prio_record);
++
++ if (pr != task_prio) {
++ sched_preempt_mask_flush(mask, task_prio);
++ atomic_set(&sched_prio_record, task_prio);
++ }
++
++ return cpumask_and(preempt_mask, allow_mask, mask);
++}
++
++static inline int select_task_rq(struct task_struct *p)
++{
++ cpumask_t allow_mask, mask;
++
++ if (unlikely(!cpumask_and(&allow_mask, p->cpus_ptr, cpu_active_mask)))
++ return select_fallback_rq(task_cpu(p), p);
++
++ if (
++#ifdef CONFIG_SCHED_SMT
++ cpumask_and(&mask, &allow_mask, &sched_sg_idle_mask) ||
++#endif
++ cpumask_and(&mask, &allow_mask, sched_idle_mask) ||
++ preempt_mask_check(p, &allow_mask, &mask))
++ return best_mask_cpu(task_cpu(p), &mask);
++
++ return best_mask_cpu(task_cpu(p), &allow_mask);
++}
++
++void sched_set_stop_task(int cpu, struct task_struct *stop)
++{
++ static struct lock_class_key stop_pi_lock;
++ struct sched_param stop_param = { .sched_priority = STOP_PRIO };
++ struct sched_param start_param = { .sched_priority = 0 };
++ struct task_struct *old_stop = cpu_rq(cpu)->stop;
++
++ if (stop) {
++ /*
++ * Make it appear like a SCHED_FIFO task, its something
++ * userspace knows about and won't get confused about.
++ *
++ * Also, it will make PI more or less work without too
++ * much confusion -- but then, stop work should not
++ * rely on PI working anyway.
++ */
++ sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param);
++
++ /*
++ * The PI code calls rt_mutex_setprio() with ->pi_lock held to
++ * adjust the effective priority of a task. As a result,
++ * rt_mutex_setprio() can trigger (RT) balancing operations,
++ * which can then trigger wakeups of the stop thread to push
++ * around the current task.
++ *
++ * The stop task itself will never be part of the PI-chain, it
++ * never blocks, therefore that ->pi_lock recursion is safe.
++ * Tell lockdep about this by placing the stop->pi_lock in its
++ * own class.
++ */
++ lockdep_set_class(&stop->pi_lock, &stop_pi_lock);
++ }
++
++ cpu_rq(cpu)->stop = stop;
++
++ if (old_stop) {
++ /*
++ * Reset it back to a normal scheduling policy so that
++ * it can die in pieces.
++ */
++ sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param);
++ }
++}
++
++static int affine_move_task(struct rq *rq, struct task_struct *p, int dest_cpu,
++ raw_spinlock_t *lock, unsigned long irq_flags)
++ __releases(rq->lock)
++ __releases(p->pi_lock)
++{
++ /* Can the task run on the task's current CPU? If so, we're done */
++ if (!cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
++ if (p->migration_disabled) {
++ if (likely(p->cpus_ptr != &p->cpus_mask))
++ __do_set_cpus_ptr(p, &p->cpus_mask);
++ p->migration_disabled = 0;
++ p->migration_flags |= MDF_FORCE_ENABLED;
++ /* When p is migrate_disabled, rq->lock should be held */
++ rq->nr_pinned--;
++ }
++
++ if (task_on_cpu(p) || READ_ONCE(p->__state) == TASK_WAKING) {
++ struct migration_arg arg = { p, dest_cpu };
++
++ /* Need help from migration thread: drop lock and wait. */
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++ stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
++ return 0;
++ }
++ if (task_on_rq_queued(p)) {
++ /*
++ * OK, since we're going to drop the lock immediately
++ * afterwards anyway.
++ */
++ update_rq_clock(rq);
++ rq = move_queued_task(rq, p, dest_cpu);
++ lock = &rq->lock;
++ }
++ }
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++ return 0;
++}
++
++static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
++ struct affinity_context *ctx,
++ struct rq *rq,
++ raw_spinlock_t *lock,
++ unsigned long irq_flags)
++{
++ const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
++ const struct cpumask *cpu_valid_mask = cpu_active_mask;
++ bool kthread = p->flags & PF_KTHREAD;
++ int dest_cpu;
++ int ret = 0;
++
++ if (kthread || is_migration_disabled(p)) {
++ /*
++ * Kernel threads are allowed on online && !active CPUs,
++ * however, during cpu-hot-unplug, even these might get pushed
++ * away if not KTHREAD_IS_PER_CPU.
++ *
++ * Specifically, migration_disabled() tasks must not fail the
++ * cpumask_any_and_distribute() pick below, esp. so on
++ * SCA_MIGRATE_ENABLE, otherwise we'll not call
++ * set_cpus_allowed_common() and actually reset p->cpus_ptr.
++ */
++ cpu_valid_mask = cpu_online_mask;
++ }
++
++ if (!kthread && !cpumask_subset(ctx->new_mask, cpu_allowed_mask)) {
++ ret = -EINVAL;
++ goto out;
++ }
++
++ /*
++ * Must re-check here, to close a race against __kthread_bind(),
++ * sched_setaffinity() is not guaranteed to observe the flag.
++ */
++ if ((ctx->flags & SCA_CHECK) && (p->flags & PF_NO_SETAFFINITY)) {
++ ret = -EINVAL;
++ goto out;
++ }
++
++ if (cpumask_equal(&p->cpus_mask, ctx->new_mask))
++ goto out;
++
++ dest_cpu = cpumask_any_and(cpu_valid_mask, ctx->new_mask);
++ if (dest_cpu >= nr_cpu_ids) {
++ ret = -EINVAL;
++ goto out;
++ }
++
++ __do_set_cpus_allowed(p, ctx);
++
++ return affine_move_task(rq, p, dest_cpu, lock, irq_flags);
++
++out:
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++
++ return ret;
++}
++
++/*
++ * Change a given task's CPU affinity. Migrate the thread to a
++ * is removed from the allowed bitmask.
++ *
++ * NOTE: the caller must have a valid reference to the task, the
++ * task must not exit() & deallocate itself prematurely. The
++ * call is not atomic; no spinlocks may be held.
++ */
++static int __set_cpus_allowed_ptr(struct task_struct *p,
++ struct affinity_context *ctx)
++{
++ unsigned long irq_flags;
++ struct rq *rq;
++ raw_spinlock_t *lock;
++
++ raw_spin_lock_irqsave(&p->pi_lock, irq_flags);
++ rq = __task_access_lock(p, &lock);
++ /*
++ * Masking should be skipped if SCA_USER or any of the SCA_MIGRATE_*
++ * flags are set.
++ */
++ if (p->user_cpus_ptr &&
++ !(ctx->flags & SCA_USER) &&
++ cpumask_and(rq->scratch_mask, ctx->new_mask, p->user_cpus_ptr))
++ ctx->new_mask = rq->scratch_mask;
++
++
++ return __set_cpus_allowed_ptr_locked(p, ctx, rq, lock, irq_flags);
++}
++
++int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
++{
++ struct affinity_context ac = {
++ .new_mask = new_mask,
++ .flags = 0,
++ };
++
++ return __set_cpus_allowed_ptr(p, &ac);
++}
++EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
++
++/*
++ * Change a given task's CPU affinity to the intersection of its current
++ * affinity mask and @subset_mask, writing the resulting mask to @new_mask.
++ * If user_cpus_ptr is defined, use it as the basis for restricting CPU
++ * affinity or use cpu_online_mask instead.
++ *
++ * If the resulting mask is empty, leave the affinity unchanged and return
++ * -EINVAL.
++ */
++static int restrict_cpus_allowed_ptr(struct task_struct *p,
++ struct cpumask *new_mask,
++ const struct cpumask *subset_mask)
++{
++ struct affinity_context ac = {
++ .new_mask = new_mask,
++ .flags = 0,
++ };
++ unsigned long irq_flags;
++ raw_spinlock_t *lock;
++ struct rq *rq;
++ int err;
++
++ raw_spin_lock_irqsave(&p->pi_lock, irq_flags);
++ rq = __task_access_lock(p, &lock);
++
++ if (!cpumask_and(new_mask, task_user_cpus(p), subset_mask)) {
++ err = -EINVAL;
++ goto err_unlock;
++ }
++
++ return __set_cpus_allowed_ptr_locked(p, &ac, rq, lock, irq_flags);
++
++err_unlock:
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++ return err;
++}
++
++/*
++ * Restrict the CPU affinity of task @p so that it is a subset of
++ * task_cpu_possible_mask() and point @p->user_cpus_ptr to a copy of the
++ * old affinity mask. If the resulting mask is empty, we warn and walk
++ * up the cpuset hierarchy until we find a suitable mask.
++ */
++void force_compatible_cpus_allowed_ptr(struct task_struct *p)
++{
++ cpumask_var_t new_mask;
++ const struct cpumask *override_mask = task_cpu_possible_mask(p);
++
++ alloc_cpumask_var(&new_mask, GFP_KERNEL);
++
++ /*
++ * __migrate_task() can fail silently in the face of concurrent
++ * offlining of the chosen destination CPU, so take the hotplug
++ * lock to ensure that the migration succeeds.
++ */
++ cpus_read_lock();
++ if (!cpumask_available(new_mask))
++ goto out_set_mask;
++
++ if (!restrict_cpus_allowed_ptr(p, new_mask, override_mask))
++ goto out_free_mask;
++
++ /*
++ * We failed to find a valid subset of the affinity mask for the
++ * task, so override it based on its cpuset hierarchy.
++ */
++ cpuset_cpus_allowed(p, new_mask);
++ override_mask = new_mask;
++
++out_set_mask:
++ if (printk_ratelimit()) {
++ printk_deferred("Overriding affinity for process %d (%s) to CPUs %*pbl\n",
++ task_pid_nr(p), p->comm,
++ cpumask_pr_args(override_mask));
++ }
++
++ WARN_ON(set_cpus_allowed_ptr(p, override_mask));
++out_free_mask:
++ cpus_read_unlock();
++ free_cpumask_var(new_mask);
++}
++
++static int
++__sched_setaffinity(struct task_struct *p, struct affinity_context *ctx);
++
++/*
++ * Restore the affinity of a task @p which was previously restricted by a
++ * call to force_compatible_cpus_allowed_ptr().
++ *
++ * It is the caller's responsibility to serialise this with any calls to
++ * force_compatible_cpus_allowed_ptr(@p).
++ */
++void relax_compatible_cpus_allowed_ptr(struct task_struct *p)
++{
++ struct affinity_context ac = {
++ .new_mask = task_user_cpus(p),
++ .flags = 0,
++ };
++ int ret;
++
++ /*
++ * Try to restore the old affinity mask with __sched_setaffinity().
++ * Cpuset masking will be done there too.
++ */
++ ret = __sched_setaffinity(p, &ac);
++ WARN_ON_ONCE(ret);
++}
++
++#else /* CONFIG_SMP */
++
++static inline int select_task_rq(struct task_struct *p)
++{
++ return 0;
++}
++
++static inline int
++__set_cpus_allowed_ptr(struct task_struct *p,
++ struct affinity_context *ctx)
++{
++ return set_cpus_allowed_ptr(p, ctx->new_mask);
++}
++
++static inline bool rq_has_pinned_tasks(struct rq *rq)
++{
++ return false;
++}
++
++static inline cpumask_t *alloc_user_cpus_ptr(int node)
++{
++ return NULL;
++}
++
++#endif /* !CONFIG_SMP */
++
++static void
++ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
++{
++ struct rq *rq;
++
++ if (!schedstat_enabled())
++ return;
++
++ rq = this_rq();
++
++#ifdef CONFIG_SMP
++ if (cpu == rq->cpu) {
++ __schedstat_inc(rq->ttwu_local);
++ __schedstat_inc(p->stats.nr_wakeups_local);
++ } else {
++ /** Alt schedule FW ToDo:
++ * How to do ttwu_wake_remote
++ */
++ }
++#endif /* CONFIG_SMP */
++
++ __schedstat_inc(rq->ttwu_count);
++ __schedstat_inc(p->stats.nr_wakeups);
++}
++
++/*
++ * Mark the task runnable.
++ */
++static inline void ttwu_do_wakeup(struct task_struct *p)
++{
++ WRITE_ONCE(p->__state, TASK_RUNNING);
++ trace_sched_wakeup(p);
++}
++
++static inline void
++ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
++{
++ if (p->sched_contributes_to_load)
++ rq->nr_uninterruptible--;
++
++ if (
++#ifdef CONFIG_SMP
++ !(wake_flags & WF_MIGRATED) &&
++#endif
++ p->in_iowait) {
++ delayacct_blkio_end(p);
++ atomic_dec(&task_rq(p)->nr_iowait);
++ }
++
++ activate_task(p, rq);
++ wakeup_preempt(rq);
++
++ ttwu_do_wakeup(p);
++}
++
++/*
++ * Consider @p being inside a wait loop:
++ *
++ * for (;;) {
++ * set_current_state(TASK_UNINTERRUPTIBLE);
++ *
++ * if (CONDITION)
++ * break;
++ *
++ * schedule();
++ * }
++ * __set_current_state(TASK_RUNNING);
++ *
++ * between set_current_state() and schedule(). In this case @p is still
++ * runnable, so all that needs doing is change p->state back to TASK_RUNNING in
++ * an atomic manner.
++ *
++ * By taking task_rq(p)->lock we serialize against schedule(), if @p->on_rq
++ * then schedule() must still happen and p->state can be changed to
++ * TASK_RUNNING. Otherwise we lost the race, schedule() has happened, and we
++ * need to do a full wakeup with enqueue.
++ *
++ * Returns: %true when the wakeup is done,
++ * %false otherwise.
++ */
++static int ttwu_runnable(struct task_struct *p, int wake_flags)
++{
++ struct rq *rq;
++ raw_spinlock_t *lock;
++ int ret = 0;
++
++ rq = __task_access_lock(p, &lock);
++ if (task_on_rq_queued(p)) {
++ if (!task_on_cpu(p)) {
++ /*
++ * When on_rq && !on_cpu the task is preempted, see if
++ * it should preempt the task that is current now.
++ */
++ update_rq_clock(rq);
++ wakeup_preempt(rq);
++ }
++ ttwu_do_wakeup(p);
++ ret = 1;
++ }
++ __task_access_unlock(p, lock);
++
++ return ret;
++}
++
++#ifdef CONFIG_SMP
++void sched_ttwu_pending(void *arg)
++{
++ struct llist_node *llist = arg;
++ struct rq *rq = this_rq();
++ struct task_struct *p, *t;
++ struct rq_flags rf;
++
++ if (!llist)
++ return;
++
++ rq_lock_irqsave(rq, &rf);
++ update_rq_clock(rq);
++
++ llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
++ if (WARN_ON_ONCE(p->on_cpu))
++ smp_cond_load_acquire(&p->on_cpu, !VAL);
++
++ if (WARN_ON_ONCE(task_cpu(p) != cpu_of(rq)))
++ set_task_cpu(p, cpu_of(rq));
++
++ ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0);
++ }
++
++ /*
++ * Must be after enqueueing at least once task such that
++ * idle_cpu() does not observe a false-negative -- if it does,
++ * it is possible for select_idle_siblings() to stack a number
++ * of tasks on this CPU during that window.
++ *
++ * It is ok to clear ttwu_pending when another task pending.
++ * We will receive IPI after local irq enabled and then enqueue it.
++ * Since now nr_running > 0, idle_cpu() will always get correct result.
++ */
++ WRITE_ONCE(rq->ttwu_pending, 0);
++ rq_unlock_irqrestore(rq, &rf);
++}
++
++/*
++ * Prepare the scene for sending an IPI for a remote smp_call
++ *
++ * Returns true if the caller can proceed with sending the IPI.
++ * Returns false otherwise.
++ */
++bool call_function_single_prep_ipi(int cpu)
++{
++ if (set_nr_if_polling(cpu_rq(cpu)->idle)) {
++ trace_sched_wake_idle_without_ipi(cpu);
++ return false;
++ }
++
++ return true;
++}
++
++/*
++ * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
++ * necessary. The wakee CPU on receipt of the IPI will queue the task
++ * via sched_ttwu_wakeup() for activation so the wakee incurs the cost
++ * of the wakeup instead of the waker.
++ */
++static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
++{
++ struct rq *rq = cpu_rq(cpu);
++
++ p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
++
++ WRITE_ONCE(rq->ttwu_pending, 1);
++ __smp_call_single_queue(cpu, &p->wake_entry.llist);
++}
++
++static inline bool ttwu_queue_cond(struct task_struct *p, int cpu)
++{
++ /*
++ * Do not complicate things with the async wake_list while the CPU is
++ * in hotplug state.
++ */
++ if (!cpu_active(cpu))
++ return false;
++
++ /* Ensure the task will still be allowed to run on the CPU. */
++ if (!cpumask_test_cpu(cpu, p->cpus_ptr))
++ return false;
++
++ /*
++ * If the CPU does not share cache, then queue the task on the
++ * remote rqs wakelist to avoid accessing remote data.
++ */
++ if (!cpus_share_cache(smp_processor_id(), cpu))
++ return true;
++
++ if (cpu == smp_processor_id())
++ return false;
++
++ /*
++ * If the wakee cpu is idle, or the task is descheduling and the
++ * only running task on the CPU, then use the wakelist to offload
++ * the task activation to the idle (or soon-to-be-idle) CPU as
++ * the current CPU is likely busy. nr_running is checked to
++ * avoid unnecessary task stacking.
++ *
++ * Note that we can only get here with (wakee) p->on_rq=0,
++ * p->on_cpu can be whatever, we've done the dequeue, so
++ * the wakee has been accounted out of ->nr_running.
++ */
++ if (!cpu_rq(cpu)->nr_running)
++ return true;
++
++ return false;
++}
++
++static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
++{
++ if (__is_defined(ALT_SCHED_TTWU_QUEUE) && ttwu_queue_cond(p, cpu)) {
++ sched_clock_cpu(cpu); /* Sync clocks across CPUs */
++ __ttwu_queue_wakelist(p, cpu, wake_flags);
++ return true;
++ }
++
++ return false;
++}
++
++void wake_up_if_idle(int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++
++ guard(rcu)();
++ if (is_idle_task(rcu_dereference(rq->curr))) {
++ guard(raw_spinlock_irqsave)(&rq->lock);
++ if (is_idle_task(rq->curr))
++ resched_curr(rq);
++ }
++}
++
++bool cpus_share_cache(int this_cpu, int that_cpu)
++{
++ if (this_cpu == that_cpu)
++ return true;
++
++ return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
++}
++#else /* !CONFIG_SMP */
++
++static inline bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
++{
++ return false;
++}
++
++#endif /* CONFIG_SMP */
++
++static inline void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
++{
++ struct rq *rq = cpu_rq(cpu);
++
++ if (ttwu_queue_wakelist(p, cpu, wake_flags))
++ return;
++
++ raw_spin_lock(&rq->lock);
++ update_rq_clock(rq);
++ ttwu_do_activate(rq, p, wake_flags);
++ raw_spin_unlock(&rq->lock);
++}
++
++/*
++ * Invoked from try_to_wake_up() to check whether the task can be woken up.
++ *
++ * The caller holds p::pi_lock if p != current or has preemption
++ * disabled when p == current.
++ *
++ * The rules of saved_state:
++ *
++ * The related locking code always holds p::pi_lock when updating
++ * p::saved_state, which means the code is fully serialized in both cases.
++ *
++ * For PREEMPT_RT, the lock wait and lock wakeups happen via TASK_RTLOCK_WAIT.
++ * No other bits set. This allows to distinguish all wakeup scenarios.
++ *
++ * For FREEZER, the wakeup happens via TASK_FROZEN. No other bits set. This
++ * allows us to prevent early wakeup of tasks before they can be run on
++ * asymmetric ISA architectures (eg ARMv9).
++ */
++static __always_inline
++bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
++{
++ int match;
++
++ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) {
++ WARN_ON_ONCE((state & TASK_RTLOCK_WAIT) &&
++ state != TASK_RTLOCK_WAIT);
++ }
++
++ *success = !!(match = __task_state_match(p, state));
++
++ /*
++ * Saved state preserves the task state across blocking on
++ * an RT lock or TASK_FREEZABLE tasks. If the state matches,
++ * set p::saved_state to TASK_RUNNING, but do not wake the task
++ * because it waits for a lock wakeup or __thaw_task(). Also
++ * indicate success because from the regular waker's point of
++ * view this has succeeded.
++ *
++ * After acquiring the lock the task will restore p::__state
++ * from p::saved_state which ensures that the regular
++ * wakeup is not lost. The restore will also set
++ * p::saved_state to TASK_RUNNING so any further tests will
++ * not result in false positives vs. @success
++ */
++ if (match < 0)
++ p->saved_state = TASK_RUNNING;
++
++ return match > 0;
++}
++
++/*
++ * Notes on Program-Order guarantees on SMP systems.
++ *
++ * MIGRATION
++ *
++ * The basic program-order guarantee on SMP systems is that when a task [t]
++ * migrates, all its activity on its old CPU [c0] happens-before any subsequent
++ * execution on its new CPU [c1].
++ *
++ * For migration (of runnable tasks) this is provided by the following means:
++ *
++ * A) UNLOCK of the rq(c0)->lock scheduling out task t
++ * B) migration for t is required to synchronize *both* rq(c0)->lock and
++ * rq(c1)->lock (if not at the same time, then in that order).
++ * C) LOCK of the rq(c1)->lock scheduling in task
++ *
++ * Transitivity guarantees that B happens after A and C after B.
++ * Note: we only require RCpc transitivity.
++ * Note: the CPU doing B need not be c0 or c1
++ *
++ * Example:
++ *
++ * CPU0 CPU1 CPU2
++ *
++ * LOCK rq(0)->lock
++ * sched-out X
++ * sched-in Y
++ * UNLOCK rq(0)->lock
++ *
++ * LOCK rq(0)->lock // orders against CPU0
++ * dequeue X
++ * UNLOCK rq(0)->lock
++ *
++ * LOCK rq(1)->lock
++ * enqueue X
++ * UNLOCK rq(1)->lock
++ *
++ * LOCK rq(1)->lock // orders against CPU2
++ * sched-out Z
++ * sched-in X
++ * UNLOCK rq(1)->lock
++ *
++ *
++ * BLOCKING -- aka. SLEEP + WAKEUP
++ *
++ * For blocking we (obviously) need to provide the same guarantee as for
++ * migration. However the means are completely different as there is no lock
++ * chain to provide order. Instead we do:
++ *
++ * 1) smp_store_release(X->on_cpu, 0) -- finish_task()
++ * 2) smp_cond_load_acquire(!X->on_cpu) -- try_to_wake_up()
++ *
++ * Example:
++ *
++ * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule)
++ *
++ * LOCK rq(0)->lock LOCK X->pi_lock
++ * dequeue X
++ * sched-out X
++ * smp_store_release(X->on_cpu, 0);
++ *
++ * smp_cond_load_acquire(&X->on_cpu, !VAL);
++ * X->state = WAKING
++ * set_task_cpu(X,2)
++ *
++ * LOCK rq(2)->lock
++ * enqueue X
++ * X->state = RUNNING
++ * UNLOCK rq(2)->lock
++ *
++ * LOCK rq(2)->lock // orders against CPU1
++ * sched-out Z
++ * sched-in X
++ * UNLOCK rq(2)->lock
++ *
++ * UNLOCK X->pi_lock
++ * UNLOCK rq(0)->lock
++ *
++ *
++ * However; for wakeups there is a second guarantee we must provide, namely we
++ * must observe the state that lead to our wakeup. That is, not only must our
++ * task observe its own prior state, it must also observe the stores prior to
++ * its wakeup.
++ *
++ * This means that any means of doing remote wakeups must order the CPU doing
++ * the wakeup against the CPU the task is going to end up running on. This,
++ * however, is already required for the regular Program-Order guarantee above,
++ * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire).
++ *
++ */
++
++/**
++ * try_to_wake_up - wake up a thread
++ * @p: the thread to be awakened
++ * @state: the mask of task states that can be woken
++ * @wake_flags: wake modifier flags (WF_*)
++ *
++ * Conceptually does:
++ *
++ * If (@state & @p->state) @p->state = TASK_RUNNING.
++ *
++ * If the task was not queued/runnable, also place it back on a runqueue.
++ *
++ * This function is atomic against schedule() which would dequeue the task.
++ *
++ * It issues a full memory barrier before accessing @p->state, see the comment
++ * with set_current_state().
++ *
++ * Uses p->pi_lock to serialize against concurrent wake-ups.
++ *
++ * Relies on p->pi_lock stabilizing:
++ * - p->sched_class
++ * - p->cpus_ptr
++ * - p->sched_task_group
++ * in order to do migration, see its use of select_task_rq()/set_task_cpu().
++ *
++ * Tries really hard to only take one task_rq(p)->lock for performance.
++ * Takes rq->lock in:
++ * - ttwu_runnable() -- old rq, unavoidable, see comment there;
++ * - ttwu_queue() -- new rq, for enqueue of the task;
++ * - psi_ttwu_dequeue() -- much sadness :-( accounting will kill us.
++ *
++ * As a consequence we race really badly with just about everything. See the
++ * many memory barriers and their comments for details.
++ *
++ * Return: %true if @p->state changes (an actual wakeup was done),
++ * %false otherwise.
++ */
++int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
++{
++ guard(preempt)();
++ int cpu, success = 0;
++
++ if (p == current) {
++ /*
++ * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
++ * == smp_processor_id()'. Together this means we can special
++ * case the whole 'p->on_rq && ttwu_runnable()' case below
++ * without taking any locks.
++ *
++ * In particular:
++ * - we rely on Program-Order guarantees for all the ordering,
++ * - we're serialized against set_special_state() by virtue of
++ * it disabling IRQs (this allows not taking ->pi_lock).
++ */
++ if (!ttwu_state_match(p, state, &success))
++ goto out;
++
++ trace_sched_waking(p);
++ ttwu_do_wakeup(p);
++ goto out;
++ }
++
++ /*
++ * If we are going to wake up a thread waiting for CONDITION we
++ * need to ensure that CONDITION=1 done by the caller can not be
++ * reordered with p->state check below. This pairs with smp_store_mb()
++ * in set_current_state() that the waiting thread does.
++ */
++ scoped_guard (raw_spinlock_irqsave, &p->pi_lock) {
++ smp_mb__after_spinlock();
++ if (!ttwu_state_match(p, state, &success))
++ break;
++
++ trace_sched_waking(p);
++
++ /*
++ * Ensure we load p->on_rq _after_ p->state, otherwise it would
++ * be possible to, falsely, observe p->on_rq == 0 and get stuck
++ * in smp_cond_load_acquire() below.
++ *
++ * sched_ttwu_pending() try_to_wake_up()
++ * STORE p->on_rq = 1 LOAD p->state
++ * UNLOCK rq->lock
++ *
++ * __schedule() (switch to task 'p')
++ * LOCK rq->lock smp_rmb();
++ * smp_mb__after_spinlock();
++ * UNLOCK rq->lock
++ *
++ * [task p]
++ * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq
++ *
++ * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
++ * __schedule(). See the comment for smp_mb__after_spinlock().
++ *
++ * A similar smp_rmb() lives in __task_needs_rq_lock().
++ */
++ smp_rmb();
++ if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
++ break;
++
++#ifdef CONFIG_SMP
++ /*
++ * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
++ * possible to, falsely, observe p->on_cpu == 0.
++ *
++ * One must be running (->on_cpu == 1) in order to remove oneself
++ * from the runqueue.
++ *
++ * __schedule() (switch to task 'p') try_to_wake_up()
++ * STORE p->on_cpu = 1 LOAD p->on_rq
++ * UNLOCK rq->lock
++ *
++ * __schedule() (put 'p' to sleep)
++ * LOCK rq->lock smp_rmb();
++ * smp_mb__after_spinlock();
++ * STORE p->on_rq = 0 LOAD p->on_cpu
++ *
++ * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
++ * __schedule(). See the comment for smp_mb__after_spinlock().
++ *
++ * Form a control-dep-acquire with p->on_rq == 0 above, to ensure
++ * schedule()'s deactivate_task() has 'happened' and p will no longer
++ * care about it's own p->state. See the comment in __schedule().
++ */
++ smp_acquire__after_ctrl_dep();
++
++ /*
++ * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq
++ * == 0), which means we need to do an enqueue, change p->state to
++ * TASK_WAKING such that we can unlock p->pi_lock before doing the
++ * enqueue, such as ttwu_queue_wakelist().
++ */
++ WRITE_ONCE(p->__state, TASK_WAKING);
++
++ /*
++ * If the owning (remote) CPU is still in the middle of schedule() with
++ * this task as prev, considering queueing p on the remote CPUs wake_list
++ * which potentially sends an IPI instead of spinning on p->on_cpu to
++ * let the waker make forward progress. This is safe because IRQs are
++ * disabled and the IPI will deliver after on_cpu is cleared.
++ *
++ * Ensure we load task_cpu(p) after p->on_cpu:
++ *
++ * set_task_cpu(p, cpu);
++ * STORE p->cpu = @cpu
++ * __schedule() (switch to task 'p')
++ * LOCK rq->lock
++ * smp_mb__after_spin_lock() smp_cond_load_acquire(&p->on_cpu)
++ * STORE p->on_cpu = 1 LOAD p->cpu
++ *
++ * to ensure we observe the correct CPU on which the task is currently
++ * scheduling.
++ */
++ if (smp_load_acquire(&p->on_cpu) &&
++ ttwu_queue_wakelist(p, task_cpu(p), wake_flags))
++ break;
++
++ /*
++ * If the owning (remote) CPU is still in the middle of schedule() with
++ * this task as prev, wait until it's done referencing the task.
++ *
++ * Pairs with the smp_store_release() in finish_task().
++ *
++ * This ensures that tasks getting woken will be fully ordered against
++ * their previous state and preserve Program Order.
++ */
++ smp_cond_load_acquire(&p->on_cpu, !VAL);
++
++ sched_task_ttwu(p);
++
++ if ((wake_flags & WF_CURRENT_CPU) &&
++ cpumask_test_cpu(smp_processor_id(), p->cpus_ptr))
++ cpu = smp_processor_id();
++ else
++ cpu = select_task_rq(p);
++
++ if (cpu != task_cpu(p)) {
++ if (p->in_iowait) {
++ delayacct_blkio_end(p);
++ atomic_dec(&task_rq(p)->nr_iowait);
++ }
++
++ wake_flags |= WF_MIGRATED;
++ set_task_cpu(p, cpu);
++ }
++#else
++ sched_task_ttwu(p);
++
++ cpu = task_cpu(p);
++#endif /* CONFIG_SMP */
++
++ ttwu_queue(p, cpu, wake_flags);
++ }
++out:
++ if (success)
++ ttwu_stat(p, task_cpu(p), wake_flags);
++
++ return success;
++}
++
++static bool __task_needs_rq_lock(struct task_struct *p)
++{
++ unsigned int state = READ_ONCE(p->__state);
++
++ /*
++ * Since pi->lock blocks try_to_wake_up(), we don't need rq->lock when
++ * the task is blocked. Make sure to check @state since ttwu() can drop
++ * locks at the end, see ttwu_queue_wakelist().
++ */
++ if (state == TASK_RUNNING || state == TASK_WAKING)
++ return true;
++
++ /*
++ * Ensure we load p->on_rq after p->__state, otherwise it would be
++ * possible to, falsely, observe p->on_rq == 0.
++ *
++ * See try_to_wake_up() for a longer comment.
++ */
++ smp_rmb();
++ if (p->on_rq)
++ return true;
++
++#ifdef CONFIG_SMP
++ /*
++ * Ensure the task has finished __schedule() and will not be referenced
++ * anymore. Again, see try_to_wake_up() for a longer comment.
++ */
++ smp_rmb();
++ smp_cond_load_acquire(&p->on_cpu, !VAL);
++#endif
++
++ return false;
++}
++
++/**
++ * task_call_func - Invoke a function on task in fixed state
++ * @p: Process for which the function is to be invoked, can be @current.
++ * @func: Function to invoke.
++ * @arg: Argument to function.
++ *
++ * Fix the task in it's current state by avoiding wakeups and or rq operations
++ * and call @func(@arg) on it. This function can use ->on_rq and task_curr()
++ * to work out what the state is, if required. Given that @func can be invoked
++ * with a runqueue lock held, it had better be quite lightweight.
++ *
++ * Returns:
++ * Whatever @func returns
++ */
++int task_call_func(struct task_struct *p, task_call_f func, void *arg)
++{
++ struct rq *rq = NULL;
++ struct rq_flags rf;
++ int ret;
++
++ raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
++
++ if (__task_needs_rq_lock(p))
++ rq = __task_rq_lock(p, &rf);
++
++ /*
++ * At this point the task is pinned; either:
++ * - blocked and we're holding off wakeups (pi->lock)
++ * - woken, and we're holding off enqueue (rq->lock)
++ * - queued, and we're holding off schedule (rq->lock)
++ * - running, and we're holding off de-schedule (rq->lock)
++ *
++ * The called function (@func) can use: task_curr(), p->on_rq and
++ * p->__state to differentiate between these states.
++ */
++ ret = func(p, arg);
++
++ if (rq)
++ __task_rq_unlock(rq, &rf);
++
++ raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
++ return ret;
++}
++
++/**
++ * cpu_curr_snapshot - Return a snapshot of the currently running task
++ * @cpu: The CPU on which to snapshot the task.
++ *
++ * Returns the task_struct pointer of the task "currently" running on
++ * the specified CPU. If the same task is running on that CPU throughout,
++ * the return value will be a pointer to that task's task_struct structure.
++ * If the CPU did any context switches even vaguely concurrently with the
++ * execution of this function, the return value will be a pointer to the
++ * task_struct structure of a randomly chosen task that was running on
++ * that CPU somewhere around the time that this function was executing.
++ *
++ * If the specified CPU was offline, the return value is whatever it
++ * is, perhaps a pointer to the task_struct structure of that CPU's idle
++ * task, but there is no guarantee. Callers wishing a useful return
++ * value must take some action to ensure that the specified CPU remains
++ * online throughout.
++ *
++ * This function executes full memory barriers before and after fetching
++ * the pointer, which permits the caller to confine this function's fetch
++ * with respect to the caller's accesses to other shared variables.
++ */
++struct task_struct *cpu_curr_snapshot(int cpu)
++{
++ struct task_struct *t;
++
++ smp_mb(); /* Pairing determined by caller's synchronization design. */
++ t = rcu_dereference(cpu_curr(cpu));
++ smp_mb(); /* Pairing determined by caller's synchronization design. */
++ return t;
++}
++
++/**
++ * wake_up_process - Wake up a specific process
++ * @p: The process to be woken up.
++ *
++ * Attempt to wake up the nominated process and move it to the set of runnable
++ * processes.
++ *
++ * Return: 1 if the process was woken up, 0 if it was already running.
++ *
++ * This function executes a full memory barrier before accessing the task state.
++ */
++int wake_up_process(struct task_struct *p)
++{
++ return try_to_wake_up(p, TASK_NORMAL, 0);
++}
++EXPORT_SYMBOL(wake_up_process);
++
++int wake_up_state(struct task_struct *p, unsigned int state)
++{
++ return try_to_wake_up(p, state, 0);
++}
++
++/*
++ * Perform scheduler related setup for a newly forked process p.
++ * p is forked by current.
++ *
++ * __sched_fork() is basic setup used by init_idle() too:
++ */
++static inline void __sched_fork(unsigned long clone_flags, struct task_struct *p)
++{
++ p->on_rq = 0;
++ p->on_cpu = 0;
++ p->utime = 0;
++ p->stime = 0;
++ p->sched_time = 0;
++
++#ifdef CONFIG_SCHEDSTATS
++ /* Even if schedstat is disabled, there should not be garbage */
++ memset(&p->stats, 0, sizeof(p->stats));
++#endif
++
++#ifdef CONFIG_PREEMPT_NOTIFIERS
++ INIT_HLIST_HEAD(&p->preempt_notifiers);
++#endif
++
++#ifdef CONFIG_COMPACTION
++ p->capture_control = NULL;
++#endif
++#ifdef CONFIG_SMP
++ p->wake_entry.u_flags = CSD_TYPE_TTWU;
++#endif
++ init_sched_mm_cid(p);
++}
++
++/*
++ * fork()/clone()-time setup:
++ */
++int sched_fork(unsigned long clone_flags, struct task_struct *p)
++{
++ __sched_fork(clone_flags, p);
++ /*
++ * We mark the process as NEW here. This guarantees that
++ * nobody will actually run it, and a signal or other external
++ * event cannot wake it up and insert it on the runqueue either.
++ */
++ p->__state = TASK_NEW;
++
++ /*
++ * Make sure we do not leak PI boosting priority to the child.
++ */
++ p->prio = current->normal_prio;
++
++ /*
++ * Revert to default priority/policy on fork if requested.
++ */
++ if (unlikely(p->sched_reset_on_fork)) {
++ if (task_has_rt_policy(p)) {
++ p->policy = SCHED_NORMAL;
++ p->static_prio = NICE_TO_PRIO(0);
++ p->rt_priority = 0;
++ } else if (PRIO_TO_NICE(p->static_prio) < 0)
++ p->static_prio = NICE_TO_PRIO(0);
++
++ p->prio = p->normal_prio = p->static_prio;
++
++ /*
++ * We don't need the reset flag anymore after the fork. It has
++ * fulfilled its duty:
++ */
++ p->sched_reset_on_fork = 0;
++ }
++
++#ifdef CONFIG_SCHED_INFO
++ if (unlikely(sched_info_on()))
++ memset(&p->sched_info, 0, sizeof(p->sched_info));
++#endif
++ init_task_preempt_count(p);
++
++ return 0;
++}
++
++void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs)
++{
++ unsigned long flags;
++ struct rq *rq;
++
++ /*
++ * Because we're not yet on the pid-hash, p->pi_lock isn't strictly
++ * required yet, but lockdep gets upset if rules are violated.
++ */
++ raw_spin_lock_irqsave(&p->pi_lock, flags);
++ /*
++ * Share the timeslice between parent and child, thus the
++ * total amount of pending timeslices in the system doesn't change,
++ * resulting in more scheduling fairness.
++ */
++ rq = this_rq();
++ raw_spin_lock(&rq->lock);
++
++ rq->curr->time_slice /= 2;
++ p->time_slice = rq->curr->time_slice;
++#ifdef CONFIG_SCHED_HRTICK
++ hrtick_start(rq, rq->curr->time_slice);
++#endif
++
++ if (p->time_slice < RESCHED_NS) {
++ p->time_slice = sysctl_sched_base_slice;
++ resched_curr(rq);
++ }
++ sched_task_fork(p, rq);
++ raw_spin_unlock(&rq->lock);
++
++ rseq_migrate(p);
++ /*
++ * We're setting the CPU for the first time, we don't migrate,
++ * so use __set_task_cpu().
++ */
++ __set_task_cpu(p, smp_processor_id());
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++}
++
++void sched_post_fork(struct task_struct *p)
++{
++}
++
++#ifdef CONFIG_SCHEDSTATS
++
++DEFINE_STATIC_KEY_FALSE(sched_schedstats);
++
++static void set_schedstats(bool enabled)
++{
++ if (enabled)
++ static_branch_enable(&sched_schedstats);
++ else
++ static_branch_disable(&sched_schedstats);
++}
++
++void force_schedstat_enabled(void)
++{
++ if (!schedstat_enabled()) {
++ pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
++ static_branch_enable(&sched_schedstats);
++ }
++}
++
++static int __init setup_schedstats(char *str)
++{
++ int ret = 0;
++ if (!str)
++ goto out;
++
++ if (!strcmp(str, "enable")) {
++ set_schedstats(true);
++ ret = 1;
++ } else if (!strcmp(str, "disable")) {
++ set_schedstats(false);
++ ret = 1;
++ }
++out:
++ if (!ret)
++ pr_warn("Unable to parse schedstats=\n");
++
++ return ret;
++}
++__setup("schedstats=", setup_schedstats);
++
++#ifdef CONFIG_PROC_SYSCTL
++static int sysctl_schedstats(struct ctl_table *table, int write, void *buffer,
++ size_t *lenp, loff_t *ppos)
++{
++ struct ctl_table t;
++ int err;
++ int state = static_branch_likely(&sched_schedstats);
++
++ if (write && !capable(CAP_SYS_ADMIN))
++ return -EPERM;
++
++ t = *table;
++ t.data = &state;
++ err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
++ if (err < 0)
++ return err;
++ if (write)
++ set_schedstats(state);
++ return err;
++}
++
++static struct ctl_table sched_core_sysctls[] = {
++ {
++ .procname = "sched_schedstats",
++ .data = NULL,
++ .maxlen = sizeof(unsigned int),
++ .mode = 0644,
++ .proc_handler = sysctl_schedstats,
++ .extra1 = SYSCTL_ZERO,
++ .extra2 = SYSCTL_ONE,
++ },
++ {}
++};
++static int __init sched_core_sysctl_init(void)
++{
++ register_sysctl_init("kernel", sched_core_sysctls);
++ return 0;
++}
++late_initcall(sched_core_sysctl_init);
++#endif /* CONFIG_PROC_SYSCTL */
++#endif /* CONFIG_SCHEDSTATS */
++
++/*
++ * wake_up_new_task - wake up a newly created task for the first time.
++ *
++ * This function will do some initial scheduler statistics housekeeping
++ * that must be done for every newly created context, then puts the task
++ * on the runqueue and wakes it.
++ */
++void wake_up_new_task(struct task_struct *p)
++{
++ unsigned long flags;
++ struct rq *rq;
++
++ raw_spin_lock_irqsave(&p->pi_lock, flags);
++ WRITE_ONCE(p->__state, TASK_RUNNING);
++ rq = cpu_rq(select_task_rq(p));
++#ifdef CONFIG_SMP
++ rseq_migrate(p);
++ /*
++ * Fork balancing, do it here and not earlier because:
++ * - cpus_ptr can change in the fork path
++ * - any previously selected CPU might disappear through hotplug
++ *
++ * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
++ * as we're not fully set-up yet.
++ */
++ __set_task_cpu(p, cpu_of(rq));
++#endif
++
++ raw_spin_lock(&rq->lock);
++ update_rq_clock(rq);
++
++ activate_task(p, rq);
++ trace_sched_wakeup_new(p);
++ wakeup_preempt(rq);
++
++ raw_spin_unlock(&rq->lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++}
++
++#ifdef CONFIG_PREEMPT_NOTIFIERS
++
++static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
++
++void preempt_notifier_inc(void)
++{
++ static_branch_inc(&preempt_notifier_key);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_inc);
++
++void preempt_notifier_dec(void)
++{
++ static_branch_dec(&preempt_notifier_key);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_dec);
++
++/**
++ * preempt_notifier_register - tell me when current is being preempted & rescheduled
++ * @notifier: notifier struct to register
++ */
++void preempt_notifier_register(struct preempt_notifier *notifier)
++{
++ if (!static_branch_unlikely(&preempt_notifier_key))
++ WARN(1, "registering preempt_notifier while notifiers disabled\n");
++
++ hlist_add_head(&notifier->link, &current->preempt_notifiers);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_register);
++
++/**
++ * preempt_notifier_unregister - no longer interested in preemption notifications
++ * @notifier: notifier struct to unregister
++ *
++ * This is *not* safe to call from within a preemption notifier.
++ */
++void preempt_notifier_unregister(struct preempt_notifier *notifier)
++{
++ hlist_del(&notifier->link);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
++
++static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
++{
++ struct preempt_notifier *notifier;
++
++ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
++ notifier->ops->sched_in(notifier, raw_smp_processor_id());
++}
++
++static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
++{
++ if (static_branch_unlikely(&preempt_notifier_key))
++ __fire_sched_in_preempt_notifiers(curr);
++}
++
++static void
++__fire_sched_out_preempt_notifiers(struct task_struct *curr,
++ struct task_struct *next)
++{
++ struct preempt_notifier *notifier;
++
++ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
++ notifier->ops->sched_out(notifier, next);
++}
++
++static __always_inline void
++fire_sched_out_preempt_notifiers(struct task_struct *curr,
++ struct task_struct *next)
++{
++ if (static_branch_unlikely(&preempt_notifier_key))
++ __fire_sched_out_preempt_notifiers(curr, next);
++}
++
++#else /* !CONFIG_PREEMPT_NOTIFIERS */
++
++static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
++{
++}
++
++static inline void
++fire_sched_out_preempt_notifiers(struct task_struct *curr,
++ struct task_struct *next)
++{
++}
++
++#endif /* CONFIG_PREEMPT_NOTIFIERS */
++
++static inline void prepare_task(struct task_struct *next)
++{
++ /*
++ * Claim the task as running, we do this before switching to it
++ * such that any running task will have this set.
++ *
++ * See the smp_load_acquire(&p->on_cpu) case in ttwu() and
++ * its ordering comment.
++ */
++ WRITE_ONCE(next->on_cpu, 1);
++}
++
++static inline void finish_task(struct task_struct *prev)
++{
++#ifdef CONFIG_SMP
++ /*
++ * This must be the very last reference to @prev from this CPU. After
++ * p->on_cpu is cleared, the task can be moved to a different CPU. We
++ * must ensure this doesn't happen until the switch is completely
++ * finished.
++ *
++ * In particular, the load of prev->state in finish_task_switch() must
++ * happen before this.
++ *
++ * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
++ */
++ smp_store_release(&prev->on_cpu, 0);
++#else
++ prev->on_cpu = 0;
++#endif
++}
++
++#ifdef CONFIG_SMP
++
++static void do_balance_callbacks(struct rq *rq, struct balance_callback *head)
++{
++ void (*func)(struct rq *rq);
++ struct balance_callback *next;
++
++ lockdep_assert_held(&rq->lock);
++
++ while (head) {
++ func = (void (*)(struct rq *))head->func;
++ next = head->next;
++ head->next = NULL;
++ head = next;
++
++ func(rq);
++ }
++}
++
++static void balance_push(struct rq *rq);
++
++/*
++ * balance_push_callback is a right abuse of the callback interface and plays
++ * by significantly different rules.
++ *
++ * Where the normal balance_callback's purpose is to be ran in the same context
++ * that queued it (only later, when it's safe to drop rq->lock again),
++ * balance_push_callback is specifically targeted at __schedule().
++ *
++ * This abuse is tolerated because it places all the unlikely/odd cases behind
++ * a single test, namely: rq->balance_callback == NULL.
++ */
++struct balance_callback balance_push_callback = {
++ .next = NULL,
++ .func = balance_push,
++};
++
++static inline struct balance_callback *
++__splice_balance_callbacks(struct rq *rq, bool split)
++{
++ struct balance_callback *head = rq->balance_callback;
++
++ if (likely(!head))
++ return NULL;
++
++ lockdep_assert_rq_held(rq);
++ /*
++ * Must not take balance_push_callback off the list when
++ * splice_balance_callbacks() and balance_callbacks() are not
++ * in the same rq->lock section.
++ *
++ * In that case it would be possible for __schedule() to interleave
++ * and observe the list empty.
++ */
++ if (split && head == &balance_push_callback)
++ head = NULL;
++ else
++ rq->balance_callback = NULL;
++
++ return head;
++}
++
++static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
++{
++ return __splice_balance_callbacks(rq, true);
++}
++
++static void __balance_callbacks(struct rq *rq)
++{
++ do_balance_callbacks(rq, __splice_balance_callbacks(rq, false));
++}
++
++static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
++{
++ unsigned long flags;
++
++ if (unlikely(head)) {
++ raw_spin_lock_irqsave(&rq->lock, flags);
++ do_balance_callbacks(rq, head);
++ raw_spin_unlock_irqrestore(&rq->lock, flags);
++ }
++}
++
++#else
++
++static inline void __balance_callbacks(struct rq *rq)
++{
++}
++
++static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
++{
++ return NULL;
++}
++
++static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
++{
++}
++
++#endif
++
++static inline void
++prepare_lock_switch(struct rq *rq, struct task_struct *next)
++{
++ /*
++ * Since the runqueue lock will be released by the next
++ * task (which is an invalid locking op but in the case
++ * of the scheduler it's an obvious special-case), so we
++ * do an early lockdep release here:
++ */
++ spin_release(&rq->lock.dep_map, _THIS_IP_);
++#ifdef CONFIG_DEBUG_SPINLOCK
++ /* this is a valid case when another task releases the spinlock */
++ rq->lock.owner = next;
++#endif
++}
++
++static inline void finish_lock_switch(struct rq *rq)
++{
++ /*
++ * If we are tracking spinlock dependencies then we have to
++ * fix up the runqueue lock - which gets 'carried over' from
++ * prev into current:
++ */
++ spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
++ __balance_callbacks(rq);
++ raw_spin_unlock_irq(&rq->lock);
++}
++
++/*
++ * NOP if the arch has not defined these:
++ */
++
++#ifndef prepare_arch_switch
++# define prepare_arch_switch(next) do { } while (0)
++#endif
++
++#ifndef finish_arch_post_lock_switch
++# define finish_arch_post_lock_switch() do { } while (0)
++#endif
++
++static inline void kmap_local_sched_out(void)
++{
++#ifdef CONFIG_KMAP_LOCAL
++ if (unlikely(current->kmap_ctrl.idx))
++ __kmap_local_sched_out();
++#endif
++}
++
++static inline void kmap_local_sched_in(void)
++{
++#ifdef CONFIG_KMAP_LOCAL
++ if (unlikely(current->kmap_ctrl.idx))
++ __kmap_local_sched_in();
++#endif
++}
++
++/**
++ * prepare_task_switch - prepare to switch tasks
++ * @rq: the runqueue preparing to switch
++ * @next: the task we are going to switch to.
++ *
++ * This is called with the rq lock held and interrupts off. It must
++ * be paired with a subsequent finish_task_switch after the context
++ * switch.
++ *
++ * prepare_task_switch sets up locking and calls architecture specific
++ * hooks.
++ */
++static inline void
++prepare_task_switch(struct rq *rq, struct task_struct *prev,
++ struct task_struct *next)
++{
++ kcov_prepare_switch(prev);
++ sched_info_switch(rq, prev, next);
++ perf_event_task_sched_out(prev, next);
++ rseq_preempt(prev);
++ fire_sched_out_preempt_notifiers(prev, next);
++ kmap_local_sched_out();
++ prepare_task(next);
++ prepare_arch_switch(next);
++}
++
++/**
++ * finish_task_switch - clean up after a task-switch
++ * @rq: runqueue associated with task-switch
++ * @prev: the thread we just switched away from.
++ *
++ * finish_task_switch must be called after the context switch, paired
++ * with a prepare_task_switch call before the context switch.
++ * finish_task_switch will reconcile locking set up by prepare_task_switch,
++ * and do any other architecture-specific cleanup actions.
++ *
++ * Note that we may have delayed dropping an mm in context_switch(). If
++ * so, we finish that here outside of the runqueue lock. (Doing it
++ * with the lock held can cause deadlocks; see schedule() for
++ * details.)
++ *
++ * The context switch have flipped the stack from under us and restored the
++ * local variables which were saved when this task called schedule() in the
++ * past. prev == current is still correct but we need to recalculate this_rq
++ * because prev may have moved to another CPU.
++ */
++static struct rq *finish_task_switch(struct task_struct *prev)
++ __releases(rq->lock)
++{
++ struct rq *rq = this_rq();
++ struct mm_struct *mm = rq->prev_mm;
++ unsigned int prev_state;
++
++ /*
++ * The previous task will have left us with a preempt_count of 2
++ * because it left us after:
++ *
++ * schedule()
++ * preempt_disable(); // 1
++ * __schedule()
++ * raw_spin_lock_irq(&rq->lock) // 2
++ *
++ * Also, see FORK_PREEMPT_COUNT.
++ */
++ if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
++ "corrupted preempt_count: %s/%d/0x%x\n",
++ current->comm, current->pid, preempt_count()))
++ preempt_count_set(FORK_PREEMPT_COUNT);
++
++ rq->prev_mm = NULL;
++
++ /*
++ * A task struct has one reference for the use as "current".
++ * If a task dies, then it sets TASK_DEAD in tsk->state and calls
++ * schedule one last time. The schedule call will never return, and
++ * the scheduled task must drop that reference.
++ *
++ * We must observe prev->state before clearing prev->on_cpu (in
++ * finish_task), otherwise a concurrent wakeup can get prev
++ * running on another CPU and we could rave with its RUNNING -> DEAD
++ * transition, resulting in a double drop.
++ */
++ prev_state = READ_ONCE(prev->__state);
++ vtime_task_switch(prev);
++ perf_event_task_sched_in(prev, current);
++ finish_task(prev);
++ tick_nohz_task_switch();
++ finish_lock_switch(rq);
++ finish_arch_post_lock_switch();
++ kcov_finish_switch(current);
++ /*
++ * kmap_local_sched_out() is invoked with rq::lock held and
++ * interrupts disabled. There is no requirement for that, but the
++ * sched out code does not have an interrupt enabled section.
++ * Restoring the maps on sched in does not require interrupts being
++ * disabled either.
++ */
++ kmap_local_sched_in();
++
++ fire_sched_in_preempt_notifiers(current);
++ /*
++ * When switching through a kernel thread, the loop in
++ * membarrier_{private,global}_expedited() may have observed that
++ * kernel thread and not issued an IPI. It is therefore possible to
++ * schedule between user->kernel->user threads without passing though
++ * switch_mm(). Membarrier requires a barrier after storing to
++ * rq->curr, before returning to userspace, so provide them here:
++ *
++ * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
++ * provided by mmdrop(),
++ * - a sync_core for SYNC_CORE.
++ */
++ if (mm) {
++ membarrier_mm_sync_core_before_usermode(mm);
++ mmdrop_sched(mm);
++ }
++ if (unlikely(prev_state == TASK_DEAD)) {
++ /* Task is done with its stack. */
++ put_task_stack(prev);
++
++ put_task_struct_rcu_user(prev);
++ }
++
++ return rq;
++}
++
++/**
++ * schedule_tail - first thing a freshly forked thread must call.
++ * @prev: the thread we just switched away from.
++ */
++asmlinkage __visible void schedule_tail(struct task_struct *prev)
++ __releases(rq->lock)
++{
++ /*
++ * New tasks start with FORK_PREEMPT_COUNT, see there and
++ * finish_task_switch() for details.
++ *
++ * finish_task_switch() will drop rq->lock() and lower preempt_count
++ * and the preempt_enable() will end up enabling preemption (on
++ * PREEMPT_COUNT kernels).
++ */
++
++ finish_task_switch(prev);
++ preempt_enable();
++
++ if (current->set_child_tid)
++ put_user(task_pid_vnr(current), current->set_child_tid);
++
++ calculate_sigpending();
++}
++
++/*
++ * context_switch - switch to the new MM and the new thread's register state.
++ */
++static __always_inline struct rq *
++context_switch(struct rq *rq, struct task_struct *prev,
++ struct task_struct *next)
++{
++ prepare_task_switch(rq, prev, next);
++
++ /*
++ * For paravirt, this is coupled with an exit in switch_to to
++ * combine the page table reload and the switch backend into
++ * one hypercall.
++ */
++ arch_start_context_switch(prev);
++
++ /*
++ * kernel -> kernel lazy + transfer active
++ * user -> kernel lazy + mmgrab() active
++ *
++ * kernel -> user switch + mmdrop() active
++ * user -> user switch
++ *
++ * switch_mm_cid() needs to be updated if the barriers provided
++ * by context_switch() are modified.
++ */
++ if (!next->mm) { // to kernel
++ enter_lazy_tlb(prev->active_mm, next);
++
++ next->active_mm = prev->active_mm;
++ if (prev->mm) // from user
++ mmgrab(prev->active_mm);
++ else
++ prev->active_mm = NULL;
++ } else { // to user
++ membarrier_switch_mm(rq, prev->active_mm, next->mm);
++ /*
++ * sys_membarrier() requires an smp_mb() between setting
++ * rq->curr / membarrier_switch_mm() and returning to userspace.
++ *
++ * The below provides this either through switch_mm(), or in
++ * case 'prev->active_mm == next->mm' through
++ * finish_task_switch()'s mmdrop().
++ */
++ switch_mm_irqs_off(prev->active_mm, next->mm, next);
++ lru_gen_use_mm(next->mm);
++
++ if (!prev->mm) { // from kernel
++ /* will mmdrop() in finish_task_switch(). */
++ rq->prev_mm = prev->active_mm;
++ prev->active_mm = NULL;
++ }
++ }
++
++ /* switch_mm_cid() requires the memory barriers above. */
++ switch_mm_cid(rq, prev, next);
++
++ prepare_lock_switch(rq, next);
++
++ /* Here we just switch the register state and the stack. */
++ switch_to(prev, next, prev);
++ barrier();
++
++ return finish_task_switch(prev);
++}
++
++/*
++ * nr_running, nr_uninterruptible and nr_context_switches:
++ *
++ * externally visible scheduler statistics: current number of runnable
++ * threads, total number of context switches performed since bootup.
++ */
++unsigned int nr_running(void)
++{
++ unsigned int i, sum = 0;
++
++ for_each_online_cpu(i)
++ sum += cpu_rq(i)->nr_running;
++
++ return sum;
++}
++
++/*
++ * Check if only the current task is running on the CPU.
++ *
++ * Caution: this function does not check that the caller has disabled
++ * preemption, thus the result might have a time-of-check-to-time-of-use
++ * race. The caller is responsible to use it correctly, for example:
++ *
++ * - from a non-preemptible section (of course)
++ *
++ * - from a thread that is bound to a single CPU
++ *
++ * - in a loop with very short iterations (e.g. a polling loop)
++ */
++bool single_task_running(void)
++{
++ return raw_rq()->nr_running == 1;
++}
++EXPORT_SYMBOL(single_task_running);
++
++unsigned long long nr_context_switches_cpu(int cpu)
++{
++ return cpu_rq(cpu)->nr_switches;
++}
++
++unsigned long long nr_context_switches(void)
++{
++ int i;
++ unsigned long long sum = 0;
++
++ for_each_possible_cpu(i)
++ sum += cpu_rq(i)->nr_switches;
++
++ return sum;
++}
++
++/*
++ * Consumers of these two interfaces, like for example the cpuidle menu
++ * governor, are using nonsensical data. Preferring shallow idle state selection
++ * for a CPU that has IO-wait which might not even end up running the task when
++ * it does become runnable.
++ */
++
++unsigned int nr_iowait_cpu(int cpu)
++{
++ return atomic_read(&cpu_rq(cpu)->nr_iowait);
++}
++
++/*
++ * IO-wait accounting, and how it's mostly bollocks (on SMP).
++ *
++ * The idea behind IO-wait account is to account the idle time that we could
++ * have spend running if it were not for IO. That is, if we were to improve the
++ * storage performance, we'd have a proportional reduction in IO-wait time.
++ *
++ * This all works nicely on UP, where, when a task blocks on IO, we account
++ * idle time as IO-wait, because if the storage were faster, it could've been
++ * running and we'd not be idle.
++ *
++ * This has been extended to SMP, by doing the same for each CPU. This however
++ * is broken.
++ *
++ * Imagine for instance the case where two tasks block on one CPU, only the one
++ * CPU will have IO-wait accounted, while the other has regular idle. Even
++ * though, if the storage were faster, both could've ran at the same time,
++ * utilising both CPUs.
++ *
++ * This means, that when looking globally, the current IO-wait accounting on
++ * SMP is a lower bound, by reason of under accounting.
++ *
++ * Worse, since the numbers are provided per CPU, they are sometimes
++ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
++ * associated with any one particular CPU, it can wake to another CPU than it
++ * blocked on. This means the per CPU IO-wait number is meaningless.
++ *
++ * Task CPU affinities can make all that even more 'interesting'.
++ */
++
++unsigned int nr_iowait(void)
++{
++ unsigned int i, sum = 0;
++
++ for_each_possible_cpu(i)
++ sum += nr_iowait_cpu(i);
++
++ return sum;
++}
++
++#ifdef CONFIG_SMP
++
++/*
++ * sched_exec - execve() is a valuable balancing opportunity, because at
++ * this point the task has the smallest effective memory and cache
++ * footprint.
++ */
++void sched_exec(void)
++{
++}
++
++#endif
++
++DEFINE_PER_CPU(struct kernel_stat, kstat);
++DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
++
++EXPORT_PER_CPU_SYMBOL(kstat);
++EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
++
++static inline void update_curr(struct rq *rq, struct task_struct *p)
++{
++ s64 ns = rq->clock_task - p->last_ran;
++
++ p->sched_time += ns;
++ cgroup_account_cputime(p, ns);
++ account_group_exec_runtime(p, ns);
++
++ p->time_slice -= ns;
++ p->last_ran = rq->clock_task;
++}
++
++/*
++ * Return accounted runtime for the task.
++ * Return separately the current's pending runtime that have not been
++ * accounted yet.
++ */
++unsigned long long task_sched_runtime(struct task_struct *p)
++{
++ unsigned long flags;
++ struct rq *rq;
++ raw_spinlock_t *lock;
++ u64 ns;
++
++#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
++ /*
++ * 64-bit doesn't need locks to atomically read a 64-bit value.
++ * So we have a optimization chance when the task's delta_exec is 0.
++ * Reading ->on_cpu is racy, but this is ok.
++ *
++ * If we race with it leaving CPU, we'll take a lock. So we're correct.
++ * If we race with it entering CPU, unaccounted time is 0. This is
++ * indistinguishable from the read occurring a few cycles earlier.
++ * If we see ->on_cpu without ->on_rq, the task is leaving, and has
++ * been accounted, so we're correct here as well.
++ */
++ if (!p->on_cpu || !task_on_rq_queued(p))
++ return tsk_seruntime(p);
++#endif
++
++ rq = task_access_lock_irqsave(p, &lock, &flags);
++ /*
++ * Must be ->curr _and_ ->on_rq. If dequeued, we would
++ * project cycles that may never be accounted to this
++ * thread, breaking clock_gettime().
++ */
++ if (p == rq->curr && task_on_rq_queued(p)) {
++ update_rq_clock(rq);
++ update_curr(rq, p);
++ }
++ ns = tsk_seruntime(p);
++ task_access_unlock_irqrestore(p, lock, &flags);
++
++ return ns;
++}
++
++/* This manages tasks that have run out of timeslice during a scheduler_tick */
++static inline void scheduler_task_tick(struct rq *rq)
++{
++ struct task_struct *p = rq->curr;
++
++ if (is_idle_task(p))
++ return;
++
++ update_curr(rq, p);
++ cpufreq_update_util(rq, 0);
++
++ /*
++ * Tasks have less than RESCHED_NS of time slice left they will be
++ * rescheduled.
++ */
++ if (p->time_slice >= RESCHED_NS)
++ return;
++ set_tsk_need_resched(p);
++ set_preempt_need_resched();
++}
++
++#ifdef CONFIG_SCHED_DEBUG
++static u64 cpu_resched_latency(struct rq *rq)
++{
++ int latency_warn_ms = READ_ONCE(sysctl_resched_latency_warn_ms);
++ u64 resched_latency, now = rq_clock(rq);
++ static bool warned_once;
++
++ if (sysctl_resched_latency_warn_once && warned_once)
++ return 0;
++
++ if (!need_resched() || !latency_warn_ms)
++ return 0;
++
++ if (system_state == SYSTEM_BOOTING)
++ return 0;
++
++ if (!rq->last_seen_need_resched_ns) {
++ rq->last_seen_need_resched_ns = now;
++ rq->ticks_without_resched = 0;
++ return 0;
++ }
++
++ rq->ticks_without_resched++;
++ resched_latency = now - rq->last_seen_need_resched_ns;
++ if (resched_latency <= latency_warn_ms * NSEC_PER_MSEC)
++ return 0;
++
++ warned_once = true;
++
++ return resched_latency;
++}
++
++static int __init setup_resched_latency_warn_ms(char *str)
++{
++ long val;
++
++ if ((kstrtol(str, 0, &val))) {
++ pr_warn("Unable to set resched_latency_warn_ms\n");
++ return 1;
++ }
++
++ sysctl_resched_latency_warn_ms = val;
++ return 1;
++}
++__setup("resched_latency_warn_ms=", setup_resched_latency_warn_ms);
++#else
++static inline u64 cpu_resched_latency(struct rq *rq) { return 0; }
++#endif /* CONFIG_SCHED_DEBUG */
++
++/*
++ * This function gets called by the timer code, with HZ frequency.
++ * We call it with interrupts disabled.
++ */
++void scheduler_tick(void)
++{
++ int cpu __maybe_unused = smp_processor_id();
++ struct rq *rq = cpu_rq(cpu);
++ struct task_struct *curr = rq->curr;
++ u64 resched_latency;
++
++ if (housekeeping_cpu(cpu, HK_TYPE_TICK))
++ arch_scale_freq_tick();
++
++ sched_clock_tick();
++
++ raw_spin_lock(&rq->lock);
++ update_rq_clock(rq);
++
++ scheduler_task_tick(rq);
++ if (sched_feat(LATENCY_WARN))
++ resched_latency = cpu_resched_latency(rq);
++ calc_global_load_tick(rq);
++
++ task_tick_mm_cid(rq, rq->curr);
++
++ raw_spin_unlock(&rq->lock);
++
++ if (sched_feat(LATENCY_WARN) && resched_latency)
++ resched_latency_warn(cpu, resched_latency);
++
++ perf_event_task_tick();
++
++ if (curr->flags & PF_WQ_WORKER)
++ wq_worker_tick(curr);
++}
++
++#ifdef CONFIG_SCHED_SMT
++static inline int sg_balance_cpu_stop(void *data)
++{
++ struct rq *rq = this_rq();
++ struct task_struct *p = data;
++ cpumask_t tmp;
++ unsigned long flags;
++
++ local_irq_save(flags);
++
++ raw_spin_lock(&p->pi_lock);
++ raw_spin_lock(&rq->lock);
++
++ rq->active_balance = 0;
++ /* _something_ may have changed the task, double check again */
++ if (task_on_rq_queued(p) && task_rq(p) == rq &&
++ cpumask_and(&tmp, p->cpus_ptr, &sched_sg_idle_mask) &&
++ !is_migration_disabled(p)) {
++ int cpu = cpu_of(rq);
++ int dcpu = __best_mask_cpu(&tmp, per_cpu(sched_cpu_llc_mask, cpu));
++ rq = move_queued_task(rq, p, dcpu);
++ }
++
++ raw_spin_unlock(&rq->lock);
++ raw_spin_unlock(&p->pi_lock);
++
++ local_irq_restore(flags);
++
++ return 0;
++}
++
++/* sg_balance_trigger - trigger slibing group balance for @cpu */
++static inline int sg_balance_trigger(const int cpu)
++{
++ struct rq *rq= cpu_rq(cpu);
++ unsigned long flags;
++ struct task_struct *curr;
++ int res;
++
++ if (!raw_spin_trylock_irqsave(&rq->lock, flags))
++ return 0;
++ curr = rq->curr;
++ res = (!is_idle_task(curr)) && (1 == rq->nr_running) &&\
++ cpumask_intersects(curr->cpus_ptr, &sched_sg_idle_mask) &&\
++ !is_migration_disabled(curr) && (!rq->active_balance);
++
++ if (res)
++ rq->active_balance = 1;
++
++ raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++ if (res)
++ stop_one_cpu_nowait(cpu, sg_balance_cpu_stop, curr,
++ &rq->active_balance_work);
++ return res;
++}
++
++/*
++ * sg_balance - slibing group balance check for run queue @rq
++ */
++static inline void sg_balance(struct rq *rq, int cpu)
++{
++ cpumask_t chk;
++
++ /* exit when cpu is offline */
++ if (unlikely(!rq->online))
++ return;
++
++ /*
++ * Only cpu in slibing idle group will do the checking and then
++ * find potential cpus which can migrate the current running task
++ */
++ if (cpumask_test_cpu(cpu, &sched_sg_idle_mask) &&
++ cpumask_andnot(&chk, cpu_online_mask, sched_idle_mask) &&
++ cpumask_andnot(&chk, &chk, &sched_rq_pending_mask)) {
++ int i;
++
++ for_each_cpu_wrap(i, &chk, cpu) {
++ if (!cpumask_intersects(cpu_smt_mask(i), sched_idle_mask) &&\
++ sg_balance_trigger(i))
++ return;
++ }
++ }
++}
++#endif /* CONFIG_SCHED_SMT */
++
++#ifdef CONFIG_NO_HZ_FULL
++
++struct tick_work {
++ int cpu;
++ atomic_t state;
++ struct delayed_work work;
++};
++/* Values for ->state, see diagram below. */
++#define TICK_SCHED_REMOTE_OFFLINE 0
++#define TICK_SCHED_REMOTE_OFFLINING 1
++#define TICK_SCHED_REMOTE_RUNNING 2
++
++/*
++ * State diagram for ->state:
++ *
++ *
++ * TICK_SCHED_REMOTE_OFFLINE
++ * | ^
++ * | |
++ * | | sched_tick_remote()
++ * | |
++ * | |
++ * +--TICK_SCHED_REMOTE_OFFLINING
++ * | ^
++ * | |
++ * sched_tick_start() | | sched_tick_stop()
++ * | |
++ * V |
++ * TICK_SCHED_REMOTE_RUNNING
++ *
++ *
++ * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
++ * and sched_tick_start() are happy to leave the state in RUNNING.
++ */
++
++static struct tick_work __percpu *tick_work_cpu;
++
++static void sched_tick_remote(struct work_struct *work)
++{
++ struct delayed_work *dwork = to_delayed_work(work);
++ struct tick_work *twork = container_of(dwork, struct tick_work, work);
++ int cpu = twork->cpu;
++ struct rq *rq = cpu_rq(cpu);
++ int os;
++
++ /*
++ * Handle the tick only if it appears the remote CPU is running in full
++ * dynticks mode. The check is racy by nature, but missing a tick or
++ * having one too much is no big deal because the scheduler tick updates
++ * statistics and checks timeslices in a time-independent way, regardless
++ * of when exactly it is running.
++ */
++ if (tick_nohz_tick_stopped_cpu(cpu)) {
++ guard(raw_spinlock_irqsave)(&rq->lock);
++ struct task_struct *curr = rq->curr;
++
++ if (cpu_online(cpu)) {
++ update_rq_clock(rq);
++
++ if (!is_idle_task(curr)) {
++ /*
++ * Make sure the next tick runs within a
++ * reasonable amount of time.
++ */
++ u64 delta = rq_clock_task(rq) - curr->last_ran;
++ WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
++ }
++ scheduler_task_tick(rq);
++
++ calc_load_nohz_remote(rq);
++ }
++ }
++
++ /*
++ * Run the remote tick once per second (1Hz). This arbitrary
++ * frequency is large enough to avoid overload but short enough
++ * to keep scheduler internal stats reasonably up to date. But
++ * first update state to reflect hotplug activity if required.
++ */
++ os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
++ WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
++ if (os == TICK_SCHED_REMOTE_RUNNING)
++ queue_delayed_work(system_unbound_wq, dwork, HZ);
++}
++
++static void sched_tick_start(int cpu)
++{
++ int os;
++ struct tick_work *twork;
++
++ if (housekeeping_cpu(cpu, HK_TYPE_TICK))
++ return;
++
++ WARN_ON_ONCE(!tick_work_cpu);
++
++ twork = per_cpu_ptr(tick_work_cpu, cpu);
++ os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
++ WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
++ if (os == TICK_SCHED_REMOTE_OFFLINE) {
++ twork->cpu = cpu;
++ INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
++ queue_delayed_work(system_unbound_wq, &twork->work, HZ);
++ }
++}
++
++#ifdef CONFIG_HOTPLUG_CPU
++static void sched_tick_stop(int cpu)
++{
++ struct tick_work *twork;
++ int os;
++
++ if (housekeeping_cpu(cpu, HK_TYPE_TICK))
++ return;
++
++ WARN_ON_ONCE(!tick_work_cpu);
++
++ twork = per_cpu_ptr(tick_work_cpu, cpu);
++ /* There cannot be competing actions, but don't rely on stop-machine. */
++ os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_OFFLINING);
++ WARN_ON_ONCE(os != TICK_SCHED_REMOTE_RUNNING);
++ /* Don't cancel, as this would mess up the state machine. */
++}
++#endif /* CONFIG_HOTPLUG_CPU */
++
++int __init sched_tick_offload_init(void)
++{
++ tick_work_cpu = alloc_percpu(struct tick_work);
++ BUG_ON(!tick_work_cpu);
++ return 0;
++}
++
++#else /* !CONFIG_NO_HZ_FULL */
++static inline void sched_tick_start(int cpu) { }
++static inline void sched_tick_stop(int cpu) { }
++#endif
++
++#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
++ defined(CONFIG_PREEMPT_TRACER))
++/*
++ * If the value passed in is equal to the current preempt count
++ * then we just disabled preemption. Start timing the latency.
++ */
++static inline void preempt_latency_start(int val)
++{
++ if (preempt_count() == val) {
++ unsigned long ip = get_lock_parent_ip();
++#ifdef CONFIG_DEBUG_PREEMPT
++ current->preempt_disable_ip = ip;
++#endif
++ trace_preempt_off(CALLER_ADDR0, ip);
++ }
++}
++
++void preempt_count_add(int val)
++{
++#ifdef CONFIG_DEBUG_PREEMPT
++ /*
++ * Underflow?
++ */
++ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
++ return;
++#endif
++ __preempt_count_add(val);
++#ifdef CONFIG_DEBUG_PREEMPT
++ /*
++ * Spinlock count overflowing soon?
++ */
++ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
++ PREEMPT_MASK - 10);
++#endif
++ preempt_latency_start(val);
++}
++EXPORT_SYMBOL(preempt_count_add);
++NOKPROBE_SYMBOL(preempt_count_add);
++
++/*
++ * If the value passed in equals to the current preempt count
++ * then we just enabled preemption. Stop timing the latency.
++ */
++static inline void preempt_latency_stop(int val)
++{
++ if (preempt_count() == val)
++ trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
++}
++
++void preempt_count_sub(int val)
++{
++#ifdef CONFIG_DEBUG_PREEMPT
++ /*
++ * Underflow?
++ */
++ if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
++ return;
++ /*
++ * Is the spinlock portion underflowing?
++ */
++ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
++ !(preempt_count() & PREEMPT_MASK)))
++ return;
++#endif
++
++ preempt_latency_stop(val);
++ __preempt_count_sub(val);
++}
++EXPORT_SYMBOL(preempt_count_sub);
++NOKPROBE_SYMBOL(preempt_count_sub);
++
++#else
++static inline void preempt_latency_start(int val) { }
++static inline void preempt_latency_stop(int val) { }
++#endif
++
++static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
++{
++#ifdef CONFIG_DEBUG_PREEMPT
++ return p->preempt_disable_ip;
++#else
++ return 0;
++#endif
++}
++
++/*
++ * Print scheduling while atomic bug:
++ */
++static noinline void __schedule_bug(struct task_struct *prev)
++{
++ /* Save this before calling printk(), since that will clobber it */
++ unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
++
++ if (oops_in_progress)
++ return;
++
++ printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
++ prev->comm, prev->pid, preempt_count());
++
++ debug_show_held_locks(prev);
++ print_modules();
++ if (irqs_disabled())
++ print_irqtrace_events(prev);
++ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) {
++ pr_err("Preemption disabled at:");
++ print_ip_sym(KERN_ERR, preempt_disable_ip);
++ }
++ check_panic_on_warn("scheduling while atomic");
++
++ dump_stack();
++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++
++/*
++ * Various schedule()-time debugging checks and statistics:
++ */
++static inline void schedule_debug(struct task_struct *prev, bool preempt)
++{
++#ifdef CONFIG_SCHED_STACK_END_CHECK
++ if (task_stack_end_corrupted(prev))
++ panic("corrupted stack end detected inside scheduler\n");
++
++ if (task_scs_end_corrupted(prev))
++ panic("corrupted shadow stack detected inside scheduler\n");
++#endif
++
++#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
++ if (!preempt && READ_ONCE(prev->__state) && prev->non_block_count) {
++ printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
++ prev->comm, prev->pid, prev->non_block_count);
++ dump_stack();
++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++ }
++#endif
++
++ if (unlikely(in_atomic_preempt_off())) {
++ __schedule_bug(prev);
++ preempt_count_set(PREEMPT_DISABLED);
++ }
++ rcu_sleep_check();
++ SCHED_WARN_ON(ct_state() == CONTEXT_USER);
++
++ profile_hit(SCHED_PROFILING, __builtin_return_address(0));
++
++ schedstat_inc(this_rq()->sched_count);
++}
++
++#ifdef ALT_SCHED_DEBUG
++void alt_sched_debug(void)
++{
++ printk(KERN_INFO "sched: pending: 0x%04lx, idle: 0x%04lx, sg_idle: 0x%04lx\n",
++ sched_rq_pending_mask.bits[0],
++ sched_idle_mask->bits[0],
++ sched_sg_idle_mask.bits[0]);
++}
++#else
++inline void alt_sched_debug(void) {}
++#endif
++
++#ifdef CONFIG_SMP
++
++#ifdef CONFIG_PREEMPT_RT
++#define SCHED_NR_MIGRATE_BREAK 8
++#else
++#define SCHED_NR_MIGRATE_BREAK 32
++#endif
++
++const_debug unsigned int sysctl_sched_nr_migrate = SCHED_NR_MIGRATE_BREAK;
++
++/*
++ * Migrate pending tasks in @rq to @dest_cpu
++ */
++static inline int
++migrate_pending_tasks(struct rq *rq, struct rq *dest_rq, const int dest_cpu)
++{
++ struct task_struct *p, *skip = rq->curr;
++ int nr_migrated = 0;
++ int nr_tries = min(rq->nr_running / 2, sysctl_sched_nr_migrate);
++
++ /* WA to check rq->curr is still on rq */
++ if (!task_on_rq_queued(skip))
++ return 0;
++
++ while (skip != rq->idle && nr_tries &&
++ (p = sched_rq_next_task(skip, rq)) != rq->idle) {
++ skip = sched_rq_next_task(p, rq);
++ if (cpumask_test_cpu(dest_cpu, p->cpus_ptr)) {
++ __SCHED_DEQUEUE_TASK(p, rq, 0, );
++ set_task_cpu(p, dest_cpu);
++ sched_task_sanity_check(p, dest_rq);
++ sched_mm_cid_migrate_to(dest_rq, p, cpu_of(rq));
++ __SCHED_ENQUEUE_TASK(p, dest_rq, 0);
++ nr_migrated++;
++ }
++ nr_tries--;
++ }
++
++ return nr_migrated;
++}
++
++static inline int take_other_rq_tasks(struct rq *rq, int cpu)
++{
++ struct cpumask *topo_mask, *end_mask;
++
++ if (unlikely(!rq->online))
++ return 0;
++
++ if (cpumask_empty(&sched_rq_pending_mask))
++ return 0;
++
++ topo_mask = per_cpu(sched_cpu_topo_masks, cpu) + 1;
++ end_mask = per_cpu(sched_cpu_topo_end_mask, cpu);
++ do {
++ int i;
++ for_each_cpu_and(i, &sched_rq_pending_mask, topo_mask) {
++ int nr_migrated;
++ struct rq *src_rq;
++
++ src_rq = cpu_rq(i);
++ if (!do_raw_spin_trylock(&src_rq->lock))
++ continue;
++ spin_acquire(&src_rq->lock.dep_map,
++ SINGLE_DEPTH_NESTING, 1, _RET_IP_);
++
++ if ((nr_migrated = migrate_pending_tasks(src_rq, rq, cpu))) {
++ src_rq->nr_running -= nr_migrated;
++ if (src_rq->nr_running < 2)
++ cpumask_clear_cpu(i, &sched_rq_pending_mask);
++
++ spin_release(&src_rq->lock.dep_map, _RET_IP_);
++ do_raw_spin_unlock(&src_rq->lock);
++
++ rq->nr_running += nr_migrated;
++ if (rq->nr_running > 1)
++ cpumask_set_cpu(cpu, &sched_rq_pending_mask);
++
++ update_sched_preempt_mask(rq);
++ cpufreq_update_util(rq, 0);
++
++ return 1;
++ }
++
++ spin_release(&src_rq->lock.dep_map, _RET_IP_);
++ do_raw_spin_unlock(&src_rq->lock);
++ }
++ } while (++topo_mask < end_mask);
++
++ return 0;
++}
++#endif
++
++static inline void time_slice_expired(struct task_struct *p, struct rq *rq)
++{
++ p->time_slice = sysctl_sched_base_slice;
++
++ sched_task_renew(p, rq);
++
++ if (SCHED_FIFO != p->policy && task_on_rq_queued(p))
++ requeue_task(p, rq, task_sched_prio_idx(p, rq));
++}
++
++/*
++ * Timeslices below RESCHED_NS are considered as good as expired as there's no
++ * point rescheduling when there's so little time left.
++ */
++static inline void check_curr(struct task_struct *p, struct rq *rq)
++{
++ if (unlikely(rq->idle == p))
++ return;
++
++ update_curr(rq, p);
++
++ if (p->time_slice < RESCHED_NS)
++ time_slice_expired(p, rq);
++}
++
++static inline struct task_struct *
++choose_next_task(struct rq *rq, int cpu)
++{
++ struct task_struct *next;
++
++ if (unlikely(rq->skip)) {
++ next = rq_runnable_task(rq);
++ if (next == rq->idle) {
++#ifdef CONFIG_SMP
++ if (!take_other_rq_tasks(rq, cpu)) {
++#endif
++ rq->skip = NULL;
++ schedstat_inc(rq->sched_goidle);
++ return next;
++#ifdef CONFIG_SMP
++ }
++ next = rq_runnable_task(rq);
++#endif
++ }
++ rq->skip = NULL;
++#ifdef CONFIG_HIGH_RES_TIMERS
++ hrtick_start(rq, next->time_slice);
++#endif
++ return next;
++ }
++
++ next = sched_rq_first_task(rq);
++ if (next == rq->idle) {
++#ifdef CONFIG_SMP
++ if (!take_other_rq_tasks(rq, cpu)) {
++#endif
++ schedstat_inc(rq->sched_goidle);
++ /*printk(KERN_INFO "sched: choose_next_task(%d) idle %px\n", cpu, next);*/
++ return next;
++#ifdef CONFIG_SMP
++ }
++ next = sched_rq_first_task(rq);
++#endif
++ }
++#ifdef CONFIG_HIGH_RES_TIMERS
++ hrtick_start(rq, next->time_slice);
++#endif
++ /*printk(KERN_INFO "sched: choose_next_task(%d) next %px\n", cpu, next);*/
++ return next;
++}
++
++/*
++ * Constants for the sched_mode argument of __schedule().
++ *
++ * The mode argument allows RT enabled kernels to differentiate a
++ * preemption from blocking on an 'sleeping' spin/rwlock. Note that
++ * SM_MASK_PREEMPT for !RT has all bits set, which allows the compiler to
++ * optimize the AND operation out and just check for zero.
++ */
++#define SM_NONE 0x0
++#define SM_PREEMPT 0x1
++#define SM_RTLOCK_WAIT 0x2
++
++#ifndef CONFIG_PREEMPT_RT
++# define SM_MASK_PREEMPT (~0U)
++#else
++# define SM_MASK_PREEMPT SM_PREEMPT
++#endif
++
++/*
++ * schedule() is the main scheduler function.
++ *
++ * The main means of driving the scheduler and thus entering this function are:
++ *
++ * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
++ *
++ * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
++ * paths. For example, see arch/x86/entry_64.S.
++ *
++ * To drive preemption between tasks, the scheduler sets the flag in timer
++ * interrupt handler scheduler_tick().
++ *
++ * 3. Wakeups don't really cause entry into schedule(). They add a
++ * task to the run-queue and that's it.
++ *
++ * Now, if the new task added to the run-queue preempts the current
++ * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
++ * called on the nearest possible occasion:
++ *
++ * - If the kernel is preemptible (CONFIG_PREEMPTION=y):
++ *
++ * - in syscall or exception context, at the next outmost
++ * preempt_enable(). (this might be as soon as the wake_up()'s
++ * spin_unlock()!)
++ *
++ * - in IRQ context, return from interrupt-handler to
++ * preemptible context
++ *
++ * - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
++ * then at the next:
++ *
++ * - cond_resched() call
++ * - explicit schedule() call
++ * - return from syscall or exception to user-space
++ * - return from interrupt-handler to user-space
++ *
++ * WARNING: must be called with preemption disabled!
++ */
++static void __sched notrace __schedule(unsigned int sched_mode)
++{
++ struct task_struct *prev, *next;
++ unsigned long *switch_count;
++ unsigned long prev_state;
++ struct rq *rq;
++ int cpu;
++
++ cpu = smp_processor_id();
++ rq = cpu_rq(cpu);
++ prev = rq->curr;
++
++ schedule_debug(prev, !!sched_mode);
++
++ /* by passing sched_feat(HRTICK) checking which Alt schedule FW doesn't support */
++ hrtick_clear(rq);
++
++ local_irq_disable();
++ rcu_note_context_switch(!!sched_mode);
++
++ /*
++ * Make sure that signal_pending_state()->signal_pending() below
++ * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
++ * done by the caller to avoid the race with signal_wake_up():
++ *
++ * __set_current_state(@state) signal_wake_up()
++ * schedule() set_tsk_thread_flag(p, TIF_SIGPENDING)
++ * wake_up_state(p, state)
++ * LOCK rq->lock LOCK p->pi_state
++ * smp_mb__after_spinlock() smp_mb__after_spinlock()
++ * if (signal_pending_state()) if (p->state & @state)
++ *
++ * Also, the membarrier system call requires a full memory barrier
++ * after coming from user-space, before storing to rq->curr.
++ */
++ raw_spin_lock(&rq->lock);
++ smp_mb__after_spinlock();
++
++ update_rq_clock(rq);
++
++ switch_count = &prev->nivcsw;
++ /*
++ * We must load prev->state once (task_struct::state is volatile), such
++ * that we form a control dependency vs deactivate_task() below.
++ */
++ prev_state = READ_ONCE(prev->__state);
++ if (!(sched_mode & SM_MASK_PREEMPT) && prev_state) {
++ if (signal_pending_state(prev_state, prev)) {
++ WRITE_ONCE(prev->__state, TASK_RUNNING);
++ } else {
++ prev->sched_contributes_to_load =
++ (prev_state & TASK_UNINTERRUPTIBLE) &&
++ !(prev_state & TASK_NOLOAD) &&
++ !(prev_state & TASK_FROZEN);
++
++ if (prev->sched_contributes_to_load)
++ rq->nr_uninterruptible++;
++
++ /*
++ * __schedule() ttwu()
++ * prev_state = prev->state; if (p->on_rq && ...)
++ * if (prev_state) goto out;
++ * p->on_rq = 0; smp_acquire__after_ctrl_dep();
++ * p->state = TASK_WAKING
++ *
++ * Where __schedule() and ttwu() have matching control dependencies.
++ *
++ * After this, schedule() must not care about p->state any more.
++ */
++ sched_task_deactivate(prev, rq);
++ deactivate_task(prev, rq);
++
++ if (prev->in_iowait) {
++ atomic_inc(&rq->nr_iowait);
++ delayacct_blkio_start();
++ }
++ }
++ switch_count = &prev->nvcsw;
++ }
++
++ check_curr(prev, rq);
++
++ next = choose_next_task(rq, cpu);
++ clear_tsk_need_resched(prev);
++ clear_preempt_need_resched();
++#ifdef CONFIG_SCHED_DEBUG
++ rq->last_seen_need_resched_ns = 0;
++#endif
++
++ if (likely(prev != next)) {
++#ifdef CONFIG_SCHED_BMQ
++ rq->last_ts_switch = rq->clock;
++#endif
++ next->last_ran = rq->clock_task;
++
++ /*printk(KERN_INFO "sched: %px -> %px\n", prev, next);*/
++ rq->nr_switches++;
++ /*
++ * RCU users of rcu_dereference(rq->curr) may not see
++ * changes to task_struct made by pick_next_task().
++ */
++ RCU_INIT_POINTER(rq->curr, next);
++ /*
++ * The membarrier system call requires each architecture
++ * to have a full memory barrier after updating
++ * rq->curr, before returning to user-space.
++ *
++ * Here are the schemes providing that barrier on the
++ * various architectures:
++ * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
++ * switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
++ * - finish_lock_switch() for weakly-ordered
++ * architectures where spin_unlock is a full barrier,
++ * - switch_to() for arm64 (weakly-ordered, spin_unlock
++ * is a RELEASE barrier),
++ */
++ ++*switch_count;
++
++ trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next, prev_state);
++
++ /* Also unlocks the rq: */
++ rq = context_switch(rq, prev, next);
++
++ cpu = cpu_of(rq);
++ } else {
++ __balance_callbacks(rq);
++ raw_spin_unlock_irq(&rq->lock);
++ }
++
++#ifdef CONFIG_SCHED_SMT
++ sg_balance(rq, cpu);
++#endif
++}
++
++void __noreturn do_task_dead(void)
++{
++ /* Causes final put_task_struct in finish_task_switch(): */
++ set_special_state(TASK_DEAD);
++
++ /* Tell freezer to ignore us: */
++ current->flags |= PF_NOFREEZE;
++
++ __schedule(SM_NONE);
++ BUG();
++
++ /* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
++ for (;;)
++ cpu_relax();
++}
++
++static inline void sched_submit_work(struct task_struct *tsk)
++{
++ static DEFINE_WAIT_OVERRIDE_MAP(sched_map, LD_WAIT_CONFIG);
++ unsigned int task_flags;
++
++ /*
++ * Establish LD_WAIT_CONFIG context to ensure none of the code called
++ * will use a blocking primitive -- which would lead to recursion.
++ */
++ lock_map_acquire_try(&sched_map);
++
++ task_flags = tsk->flags;
++ /*
++ * If a worker goes to sleep, notify and ask workqueue whether it
++ * wants to wake up a task to maintain concurrency.
++ */
++ if (task_flags & PF_WQ_WORKER)
++ wq_worker_sleeping(tsk);
++ else if (task_flags & PF_IO_WORKER)
++ io_wq_worker_sleeping(tsk);
++
++ /*
++ * spinlock and rwlock must not flush block requests. This will
++ * deadlock if the callback attempts to acquire a lock which is
++ * already acquired.
++ */
++ SCHED_WARN_ON(current->__state & TASK_RTLOCK_WAIT);
++
++ /*
++ * If we are going to sleep and we have plugged IO queued,
++ * make sure to submit it to avoid deadlocks.
++ */
++ blk_flush_plug(tsk->plug, true);
++
++ lock_map_release(&sched_map);
++}
++
++static void sched_update_worker(struct task_struct *tsk)
++{
++ if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
++ if (tsk->flags & PF_WQ_WORKER)
++ wq_worker_running(tsk);
++ else
++ io_wq_worker_running(tsk);
++ }
++}
++
++static __always_inline void __schedule_loop(unsigned int sched_mode)
++{
++ do {
++ preempt_disable();
++ __schedule(sched_mode);
++ sched_preempt_enable_no_resched();
++ } while (need_resched());
++}
++
++asmlinkage __visible void __sched schedule(void)
++{
++ struct task_struct *tsk = current;
++
++#ifdef CONFIG_RT_MUTEXES
++ lockdep_assert(!tsk->sched_rt_mutex);
++#endif
++
++ if (!task_is_running(tsk))
++ sched_submit_work(tsk);
++ __schedule_loop(SM_NONE);
++ sched_update_worker(tsk);
++}
++EXPORT_SYMBOL(schedule);
++
++/*
++ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
++ * state (have scheduled out non-voluntarily) by making sure that all
++ * tasks have either left the run queue or have gone into user space.
++ * As idle tasks do not do either, they must not ever be preempted
++ * (schedule out non-voluntarily).
++ *
++ * schedule_idle() is similar to schedule_preempt_disable() except that it
++ * never enables preemption because it does not call sched_submit_work().
++ */
++void __sched schedule_idle(void)
++{
++ /*
++ * As this skips calling sched_submit_work(), which the idle task does
++ * regardless because that function is a nop when the task is in a
++ * TASK_RUNNING state, make sure this isn't used someplace that the
++ * current task can be in any other state. Note, idle is always in the
++ * TASK_RUNNING state.
++ */
++ WARN_ON_ONCE(current->__state);
++ do {
++ __schedule(SM_NONE);
++ } while (need_resched());
++}
++
++#if defined(CONFIG_CONTEXT_TRACKING_USER) && !defined(CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK)
++asmlinkage __visible void __sched schedule_user(void)
++{
++ /*
++ * If we come here after a random call to set_need_resched(),
++ * or we have been woken up remotely but the IPI has not yet arrived,
++ * we haven't yet exited the RCU idle mode. Do it here manually until
++ * we find a better solution.
++ *
++ * NB: There are buggy callers of this function. Ideally we
++ * should warn if prev_state != CONTEXT_USER, but that will trigger
++ * too frequently to make sense yet.
++ */
++ enum ctx_state prev_state = exception_enter();
++ schedule();
++ exception_exit(prev_state);
++}
++#endif
++
++/**
++ * schedule_preempt_disabled - called with preemption disabled
++ *
++ * Returns with preemption disabled. Note: preempt_count must be 1
++ */
++void __sched schedule_preempt_disabled(void)
++{
++ sched_preempt_enable_no_resched();
++ schedule();
++ preempt_disable();
++}
++
++#ifdef CONFIG_PREEMPT_RT
++void __sched notrace schedule_rtlock(void)
++{
++ __schedule_loop(SM_RTLOCK_WAIT);
++}
++NOKPROBE_SYMBOL(schedule_rtlock);
++#endif
++
++static void __sched notrace preempt_schedule_common(void)
++{
++ do {
++ /*
++ * Because the function tracer can trace preempt_count_sub()
++ * and it also uses preempt_enable/disable_notrace(), if
++ * NEED_RESCHED is set, the preempt_enable_notrace() called
++ * by the function tracer will call this function again and
++ * cause infinite recursion.
++ *
++ * Preemption must be disabled here before the function
++ * tracer can trace. Break up preempt_disable() into two
++ * calls. One to disable preemption without fear of being
++ * traced. The other to still record the preemption latency,
++ * which can also be traced by the function tracer.
++ */
++ preempt_disable_notrace();
++ preempt_latency_start(1);
++ __schedule(SM_PREEMPT);
++ preempt_latency_stop(1);
++ preempt_enable_no_resched_notrace();
++
++ /*
++ * Check again in case we missed a preemption opportunity
++ * between schedule and now.
++ */
++ } while (need_resched());
++}
++
++#ifdef CONFIG_PREEMPTION
++/*
++ * This is the entry point to schedule() from in-kernel preemption
++ * off of preempt_enable.
++ */
++asmlinkage __visible void __sched notrace preempt_schedule(void)
++{
++ /*
++ * If there is a non-zero preempt_count or interrupts are disabled,
++ * we do not want to preempt the current task. Just return..
++ */
++ if (likely(!preemptible()))
++ return;
++
++ preempt_schedule_common();
++}
++NOKPROBE_SYMBOL(preempt_schedule);
++EXPORT_SYMBOL(preempt_schedule);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
++#ifndef preempt_schedule_dynamic_enabled
++#define preempt_schedule_dynamic_enabled preempt_schedule
++#define preempt_schedule_dynamic_disabled NULL
++#endif
++DEFINE_STATIC_CALL(preempt_schedule, preempt_schedule_dynamic_enabled);
++EXPORT_STATIC_CALL_TRAMP(preempt_schedule);
++#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
++static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule);
++void __sched notrace dynamic_preempt_schedule(void)
++{
++ if (!static_branch_unlikely(&sk_dynamic_preempt_schedule))
++ return;
++ preempt_schedule();
++}
++NOKPROBE_SYMBOL(dynamic_preempt_schedule);
++EXPORT_SYMBOL(dynamic_preempt_schedule);
++#endif
++#endif
++
++/**
++ * preempt_schedule_notrace - preempt_schedule called by tracing
++ *
++ * The tracing infrastructure uses preempt_enable_notrace to prevent
++ * recursion and tracing preempt enabling caused by the tracing
++ * infrastructure itself. But as tracing can happen in areas coming
++ * from userspace or just about to enter userspace, a preempt enable
++ * can occur before user_exit() is called. This will cause the scheduler
++ * to be called when the system is still in usermode.
++ *
++ * To prevent this, the preempt_enable_notrace will use this function
++ * instead of preempt_schedule() to exit user context if needed before
++ * calling the scheduler.
++ */
++asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
++{
++ enum ctx_state prev_ctx;
++
++ if (likely(!preemptible()))
++ return;
++
++ do {
++ /*
++ * Because the function tracer can trace preempt_count_sub()
++ * and it also uses preempt_enable/disable_notrace(), if
++ * NEED_RESCHED is set, the preempt_enable_notrace() called
++ * by the function tracer will call this function again and
++ * cause infinite recursion.
++ *
++ * Preemption must be disabled here before the function
++ * tracer can trace. Break up preempt_disable() into two
++ * calls. One to disable preemption without fear of being
++ * traced. The other to still record the preemption latency,
++ * which can also be traced by the function tracer.
++ */
++ preempt_disable_notrace();
++ preempt_latency_start(1);
++ /*
++ * Needs preempt disabled in case user_exit() is traced
++ * and the tracer calls preempt_enable_notrace() causing
++ * an infinite recursion.
++ */
++ prev_ctx = exception_enter();
++ __schedule(SM_PREEMPT);
++ exception_exit(prev_ctx);
++
++ preempt_latency_stop(1);
++ preempt_enable_no_resched_notrace();
++ } while (need_resched());
++}
++EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
++#ifndef preempt_schedule_notrace_dynamic_enabled
++#define preempt_schedule_notrace_dynamic_enabled preempt_schedule_notrace
++#define preempt_schedule_notrace_dynamic_disabled NULL
++#endif
++DEFINE_STATIC_CALL(preempt_schedule_notrace, preempt_schedule_notrace_dynamic_enabled);
++EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace);
++#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
++static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule_notrace);
++void __sched notrace dynamic_preempt_schedule_notrace(void)
++{
++ if (!static_branch_unlikely(&sk_dynamic_preempt_schedule_notrace))
++ return;
++ preempt_schedule_notrace();
++}
++NOKPROBE_SYMBOL(dynamic_preempt_schedule_notrace);
++EXPORT_SYMBOL(dynamic_preempt_schedule_notrace);
++#endif
++#endif
++
++#endif /* CONFIG_PREEMPTION */
++
++/*
++ * This is the entry point to schedule() from kernel preemption
++ * off of irq context.
++ * Note, that this is called and return with irqs disabled. This will
++ * protect us against recursive calling from irq.
++ */
++asmlinkage __visible void __sched preempt_schedule_irq(void)
++{
++ enum ctx_state prev_state;
++
++ /* Catch callers which need to be fixed */
++ BUG_ON(preempt_count() || !irqs_disabled());
++
++ prev_state = exception_enter();
++
++ do {
++ preempt_disable();
++ local_irq_enable();
++ __schedule(SM_PREEMPT);
++ local_irq_disable();
++ sched_preempt_enable_no_resched();
++ } while (need_resched());
++
++ exception_exit(prev_state);
++}
++
++int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
++ void *key)
++{
++ WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~(WF_SYNC|WF_CURRENT_CPU));
++ return try_to_wake_up(curr->private, mode, wake_flags);
++}
++EXPORT_SYMBOL(default_wake_function);
++
++static inline void check_task_changed(struct task_struct *p, struct rq *rq)
++{
++ /* Trigger resched if task sched_prio has been modified. */
++ if (task_on_rq_queued(p)) {
++ int idx;
++
++ update_rq_clock(rq);
++ idx = task_sched_prio_idx(p, rq);
++ if (idx != p->sq_idx) {
++ requeue_task(p, rq, idx);
++ wakeup_preempt(rq);
++ }
++ }
++}
++
++static void __setscheduler_prio(struct task_struct *p, int prio)
++{
++ p->prio = prio;
++}
++
++#ifdef CONFIG_RT_MUTEXES
++
++/*
++ * Would be more useful with typeof()/auto_type but they don't mix with
++ * bit-fields. Since it's a local thing, use int. Keep the generic sounding
++ * name such that if someone were to implement this function we get to compare
++ * notes.
++ */
++#define fetch_and_set(x, v) ({ int _x = (x); (x) = (v); _x; })
++
++void rt_mutex_pre_schedule(void)
++{
++ lockdep_assert(!fetch_and_set(current->sched_rt_mutex, 1));
++ sched_submit_work(current);
++}
++
++void rt_mutex_schedule(void)
++{
++ lockdep_assert(current->sched_rt_mutex);
++ __schedule_loop(SM_NONE);
++}
++
++void rt_mutex_post_schedule(void)
++{
++ sched_update_worker(current);
++ lockdep_assert(fetch_and_set(current->sched_rt_mutex, 0));
++}
++
++static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
++{
++ if (pi_task)
++ prio = min(prio, pi_task->prio);
++
++ return prio;
++}
++
++static inline int rt_effective_prio(struct task_struct *p, int prio)
++{
++ struct task_struct *pi_task = rt_mutex_get_top_task(p);
++
++ return __rt_effective_prio(pi_task, prio);
++}
++
++/*
++ * rt_mutex_setprio - set the current priority of a task
++ * @p: task to boost
++ * @pi_task: donor task
++ *
++ * This function changes the 'effective' priority of a task. It does
++ * not touch ->normal_prio like __setscheduler().
++ *
++ * Used by the rt_mutex code to implement priority inheritance
++ * logic. Call site only calls if the priority of the task changed.
++ */
++void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
++{
++ int prio;
++ struct rq *rq;
++ raw_spinlock_t *lock;
++
++ /* XXX used to be waiter->prio, not waiter->task->prio */
++ prio = __rt_effective_prio(pi_task, p->normal_prio);
++
++ /*
++ * If nothing changed; bail early.
++ */
++ if (p->pi_top_task == pi_task && prio == p->prio)
++ return;
++
++ rq = __task_access_lock(p, &lock);
++ /*
++ * Set under pi_lock && rq->lock, such that the value can be used under
++ * either lock.
++ *
++ * Note that there is loads of tricky to make this pointer cache work
++ * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
++ * ensure a task is de-boosted (pi_task is set to NULL) before the
++ * task is allowed to run again (and can exit). This ensures the pointer
++ * points to a blocked task -- which guarantees the task is present.
++ */
++ p->pi_top_task = pi_task;
++
++ /*
++ * For FIFO/RR we only need to set prio, if that matches we're done.
++ */
++ if (prio == p->prio)
++ goto out_unlock;
++
++ /*
++ * Idle task boosting is a nono in general. There is one
++ * exception, when PREEMPT_RT and NOHZ is active:
++ *
++ * The idle task calls get_next_timer_interrupt() and holds
++ * the timer wheel base->lock on the CPU and another CPU wants
++ * to access the timer (probably to cancel it). We can safely
++ * ignore the boosting request, as the idle CPU runs this code
++ * with interrupts disabled and will complete the lock
++ * protected section without being interrupted. So there is no
++ * real need to boost.
++ */
++ if (unlikely(p == rq->idle)) {
++ WARN_ON(p != rq->curr);
++ WARN_ON(p->pi_blocked_on);
++ goto out_unlock;
++ }
++
++ trace_sched_pi_setprio(p, pi_task);
++
++ __setscheduler_prio(p, prio);
++
++ check_task_changed(p, rq);
++out_unlock:
++ /* Avoid rq from going away on us: */
++ preempt_disable();
++
++ __balance_callbacks(rq);
++ __task_access_unlock(p, lock);
++
++ preempt_enable();
++}
++#else
++static inline int rt_effective_prio(struct task_struct *p, int prio)
++{
++ return prio;
++}
++#endif
++
++void set_user_nice(struct task_struct *p, long nice)
++{
++ unsigned long flags;
++ struct rq *rq;
++ raw_spinlock_t *lock;
++
++ if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
++ return;
++ /*
++ * We have to be careful, if called from sys_setpriority(),
++ * the task might be in the middle of scheduling on another CPU.
++ */
++ raw_spin_lock_irqsave(&p->pi_lock, flags);
++ rq = __task_access_lock(p, &lock);
++
++ p->static_prio = NICE_TO_PRIO(nice);
++ /*
++ * The RT priorities are set via sched_setscheduler(), but we still
++ * allow the 'normal' nice value to be set - but as expected
++ * it won't have any effect on scheduling until the task is
++ * not SCHED_NORMAL/SCHED_BATCH:
++ */
++ if (task_has_rt_policy(p))
++ goto out_unlock;
++
++ p->prio = effective_prio(p);
++
++ check_task_changed(p, rq);
++out_unlock:
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++}
++EXPORT_SYMBOL(set_user_nice);
++
++/*
++ * is_nice_reduction - check if nice value is an actual reduction
++ *
++ * Similar to can_nice() but does not perform a capability check.
++ *
++ * @p: task
++ * @nice: nice value
++ */
++static bool is_nice_reduction(const struct task_struct *p, const int nice)
++{
++ /* Convert nice value [19,-20] to rlimit style value [1,40]: */
++ int nice_rlim = nice_to_rlimit(nice);
++
++ return (nice_rlim <= task_rlimit(p, RLIMIT_NICE));
++}
++
++/*
++ * can_nice - check if a task can reduce its nice value
++ * @p: task
++ * @nice: nice value
++ */
++int can_nice(const struct task_struct *p, const int nice)
++{
++ return is_nice_reduction(p, nice) || capable(CAP_SYS_NICE);
++}
++
++#ifdef __ARCH_WANT_SYS_NICE
++
++/*
++ * sys_nice - change the priority of the current process.
++ * @increment: priority increment
++ *
++ * sys_setpriority is a more generic, but much slower function that
++ * does similar things.
++ */
++SYSCALL_DEFINE1(nice, int, increment)
++{
++ long nice, retval;
++
++ /*
++ * Setpriority might change our priority at the same moment.
++ * We don't have to worry. Conceptually one call occurs first
++ * and we have a single winner.
++ */
++
++ increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
++ nice = task_nice(current) + increment;
++
++ nice = clamp_val(nice, MIN_NICE, MAX_NICE);
++ if (increment < 0 && !can_nice(current, nice))
++ return -EPERM;
++
++ retval = security_task_setnice(current, nice);
++ if (retval)
++ return retval;
++
++ set_user_nice(current, nice);
++ return 0;
++}
++
++#endif
++
++/**
++ * task_prio - return the priority value of a given task.
++ * @p: the task in question.
++ *
++ * Return: The priority value as seen by users in /proc.
++ *
++ * sched policy return value kernel prio user prio/nice
++ *
++ * (BMQ)normal, batch, idle[0 ... 53] [100 ... 139] 0/[-20 ... 19]/[-7 ... 7]
++ * (PDS)normal, batch, idle[0 ... 39] 100 0/[-20 ... 19]
++ * fifo, rr [-1 ... -100] [99 ... 0] [0 ... 99]
++ */
++int task_prio(const struct task_struct *p)
++{
++ return (p->prio < MAX_RT_PRIO) ? p->prio - MAX_RT_PRIO :
++ task_sched_prio_normal(p, task_rq(p));
++}
++
++/**
++ * idle_cpu - is a given CPU idle currently?
++ * @cpu: the processor in question.
++ *
++ * Return: 1 if the CPU is currently idle. 0 otherwise.
++ */
++int idle_cpu(int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++
++ if (rq->curr != rq->idle)
++ return 0;
++
++ if (rq->nr_running)
++ return 0;
++
++#ifdef CONFIG_SMP
++ if (rq->ttwu_pending)
++ return 0;
++#endif
++
++ return 1;
++}
++
++/**
++ * idle_task - return the idle task for a given CPU.
++ * @cpu: the processor in question.
++ *
++ * Return: The idle task for the cpu @cpu.
++ */
++struct task_struct *idle_task(int cpu)
++{
++ return cpu_rq(cpu)->idle;
++}
++
++/**
++ * find_process_by_pid - find a process with a matching PID value.
++ * @pid: the pid in question.
++ *
++ * The task of @pid, if found. %NULL otherwise.
++ */
++static inline struct task_struct *find_process_by_pid(pid_t pid)
++{
++ return pid ? find_task_by_vpid(pid) : current;
++}
++
++static struct task_struct *find_get_task(pid_t pid)
++{
++ struct task_struct *p;
++ guard(rcu)();
++
++ p = find_process_by_pid(pid);
++ if (likely(p))
++ get_task_struct(p);
++
++ return p;
++}
++
++DEFINE_CLASS(find_get_task, struct task_struct *, if (_T) put_task_struct(_T),
++ find_get_task(pid), pid_t pid)
++
++/*
++ * sched_setparam() passes in -1 for its policy, to let the functions
++ * it calls know not to change it.
++ */
++#define SETPARAM_POLICY -1
++
++static void __setscheduler_params(struct task_struct *p,
++ const struct sched_attr *attr)
++{
++ int policy = attr->sched_policy;
++
++ if (policy == SETPARAM_POLICY)
++ policy = p->policy;
++
++ p->policy = policy;
++
++ /*
++ * allow normal nice value to be set, but will not have any
++ * effect on scheduling until the task not SCHED_NORMAL/
++ * SCHED_BATCH
++ */
++ p->static_prio = NICE_TO_PRIO(attr->sched_nice);
++
++ /*
++ * __sched_setscheduler() ensures attr->sched_priority == 0 when
++ * !rt_policy. Always setting this ensures that things like
++ * getparam()/getattr() don't report silly values for !rt tasks.
++ */
++ p->rt_priority = attr->sched_priority;
++ p->normal_prio = normal_prio(p);
++}
++
++/*
++ * check the target process has a UID that matches the current process's
++ */
++static bool check_same_owner(struct task_struct *p)
++{
++ const struct cred *cred = current_cred(), *pcred;
++ guard(rcu)();
++
++ pcred = __task_cred(p);
++ return (uid_eq(cred->euid, pcred->euid) ||
++ uid_eq(cred->euid, pcred->uid));
++}
++
++/*
++ * Allow unprivileged RT tasks to decrease priority.
++ * Only issue a capable test if needed and only once to avoid an audit
++ * event on permitted non-privileged operations:
++ */
++static int user_check_sched_setscheduler(struct task_struct *p,
++ const struct sched_attr *attr,
++ int policy, int reset_on_fork)
++{
++ if (rt_policy(policy)) {
++ unsigned long rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
++
++ /* Can't set/change the rt policy: */
++ if (policy != p->policy && !rlim_rtprio)
++ goto req_priv;
++
++ /* Can't increase priority: */
++ if (attr->sched_priority > p->rt_priority &&
++ attr->sched_priority > rlim_rtprio)
++ goto req_priv;
++ }
++
++ /* Can't change other user's priorities: */
++ if (!check_same_owner(p))
++ goto req_priv;
++
++ /* Normal users shall not reset the sched_reset_on_fork flag: */
++ if (p->sched_reset_on_fork && !reset_on_fork)
++ goto req_priv;
++
++ return 0;
++
++req_priv:
++ if (!capable(CAP_SYS_NICE))
++ return -EPERM;
++
++ return 0;
++}
++
++static int __sched_setscheduler(struct task_struct *p,
++ const struct sched_attr *attr,
++ bool user, bool pi)
++{
++ const struct sched_attr dl_squash_attr = {
++ .size = sizeof(struct sched_attr),
++ .sched_policy = SCHED_FIFO,
++ .sched_nice = 0,
++ .sched_priority = 99,
++ };
++ int oldpolicy = -1, policy = attr->sched_policy;
++ int retval, newprio;
++ struct balance_callback *head;
++ unsigned long flags;
++ struct rq *rq;
++ int reset_on_fork;
++ raw_spinlock_t *lock;
++
++ /* The pi code expects interrupts enabled */
++ BUG_ON(pi && in_interrupt());
++
++ /*
++ * Alt schedule FW supports SCHED_DEADLINE by squash it as prio 0 SCHED_FIFO
++ */
++ if (unlikely(SCHED_DEADLINE == policy)) {
++ attr = &dl_squash_attr;
++ policy = attr->sched_policy;
++ }
++recheck:
++ /* Double check policy once rq lock held */
++ if (policy < 0) {
++ reset_on_fork = p->sched_reset_on_fork;
++ policy = oldpolicy = p->policy;
++ } else {
++ reset_on_fork = !!(attr->sched_flags & SCHED_RESET_ON_FORK);
++
++ if (policy > SCHED_IDLE)
++ return -EINVAL;
++ }
++
++ if (attr->sched_flags & ~(SCHED_FLAG_ALL))
++ return -EINVAL;
++
++ /*
++ * Valid priorities for SCHED_FIFO and SCHED_RR are
++ * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL and
++ * SCHED_BATCH and SCHED_IDLE is 0.
++ */
++ if (attr->sched_priority < 0 ||
++ (p->mm && attr->sched_priority > MAX_RT_PRIO - 1) ||
++ (!p->mm && attr->sched_priority > MAX_RT_PRIO - 1))
++ return -EINVAL;
++ if ((SCHED_RR == policy || SCHED_FIFO == policy) !=
++ (attr->sched_priority != 0))
++ return -EINVAL;
++
++ if (user) {
++ retval = user_check_sched_setscheduler(p, attr, policy, reset_on_fork);
++ if (retval)
++ return retval;
++
++ retval = security_task_setscheduler(p);
++ if (retval)
++ return retval;
++ }
++
++ /*
++ * Make sure no PI-waiters arrive (or leave) while we are
++ * changing the priority of the task:
++ */
++ raw_spin_lock_irqsave(&p->pi_lock, flags);
++
++ /*
++ * To be able to change p->policy safely, task_access_lock()
++ * must be called.
++ * IF use task_access_lock() here:
++ * For the task p which is not running, reading rq->stop is
++ * racy but acceptable as ->stop doesn't change much.
++ * An enhancemnet can be made to read rq->stop saftly.
++ */
++ rq = __task_access_lock(p, &lock);
++
++ /*
++ * Changing the policy of the stop threads its a very bad idea
++ */
++ if (p == rq->stop) {
++ retval = -EINVAL;
++ goto unlock;
++ }
++
++ /*
++ * If not changing anything there's no need to proceed further:
++ */
++ if (unlikely(policy == p->policy)) {
++ if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
++ goto change;
++ if (!rt_policy(policy) &&
++ NICE_TO_PRIO(attr->sched_nice) != p->static_prio)
++ goto change;
++
++ p->sched_reset_on_fork = reset_on_fork;
++ retval = 0;
++ goto unlock;
++ }
++change:
++
++ /* Re-check policy now with rq lock held */
++ if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
++ policy = oldpolicy = -1;
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++ goto recheck;
++ }
++
++ p->sched_reset_on_fork = reset_on_fork;
++
++ newprio = __normal_prio(policy, attr->sched_priority, NICE_TO_PRIO(attr->sched_nice));
++ if (pi) {
++ /*
++ * Take priority boosted tasks into account. If the new
++ * effective priority is unchanged, we just store the new
++ * normal parameters and do not touch the scheduler class and
++ * the runqueue. This will be done when the task deboost
++ * itself.
++ */
++ newprio = rt_effective_prio(p, newprio);
++ }
++
++ if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
++ __setscheduler_params(p, attr);
++ __setscheduler_prio(p, newprio);
++ }
++
++ check_task_changed(p, rq);
++
++ /* Avoid rq from going away on us: */
++ preempt_disable();
++ head = splice_balance_callbacks(rq);
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++
++ if (pi)
++ rt_mutex_adjust_pi(p);
++
++ /* Run balance callbacks after we've adjusted the PI chain: */
++ balance_callbacks(rq, head);
++ preempt_enable();
++
++ return 0;
++
++unlock:
++ __task_access_unlock(p, lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++ return retval;
++}
++
++static int _sched_setscheduler(struct task_struct *p, int policy,
++ const struct sched_param *param, bool check)
++{
++ struct sched_attr attr = {
++ .sched_policy = policy,
++ .sched_priority = param->sched_priority,
++ .sched_nice = PRIO_TO_NICE(p->static_prio),
++ };
++
++ /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
++ if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
++ attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
++ policy &= ~SCHED_RESET_ON_FORK;
++ attr.sched_policy = policy;
++ }
++
++ return __sched_setscheduler(p, &attr, check, true);
++}
++
++/**
++ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
++ * @p: the task in question.
++ * @policy: new policy.
++ * @param: structure containing the new RT priority.
++ *
++ * Use sched_set_fifo(), read its comment.
++ *
++ * Return: 0 on success. An error code otherwise.
++ *
++ * NOTE that the task may be already dead.
++ */
++int sched_setscheduler(struct task_struct *p, int policy,
++ const struct sched_param *param)
++{
++ return _sched_setscheduler(p, policy, param, true);
++}
++
++int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
++{
++ return __sched_setscheduler(p, attr, true, true);
++}
++
++int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
++{
++ return __sched_setscheduler(p, attr, false, true);
++}
++EXPORT_SYMBOL_GPL(sched_setattr_nocheck);
++
++/**
++ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
++ * @p: the task in question.
++ * @policy: new policy.
++ * @param: structure containing the new RT priority.
++ *
++ * Just like sched_setscheduler, only don't bother checking if the
++ * current context has permission. For example, this is needed in
++ * stop_machine(): we create temporary high priority worker threads,
++ * but our caller might not have that capability.
++ *
++ * Return: 0 on success. An error code otherwise.
++ */
++int sched_setscheduler_nocheck(struct task_struct *p, int policy,
++ const struct sched_param *param)
++{
++ return _sched_setscheduler(p, policy, param, false);
++}
++
++/*
++ * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally
++ * incapable of resource management, which is the one thing an OS really should
++ * be doing.
++ *
++ * This is of course the reason it is limited to privileged users only.
++ *
++ * Worse still; it is fundamentally impossible to compose static priority
++ * workloads. You cannot take two correctly working static prio workloads
++ * and smash them together and still expect them to work.
++ *
++ * For this reason 'all' FIFO tasks the kernel creates are basically at:
++ *
++ * MAX_RT_PRIO / 2
++ *
++ * The administrator _MUST_ configure the system, the kernel simply doesn't
++ * know enough information to make a sensible choice.
++ */
++void sched_set_fifo(struct task_struct *p)
++{
++ struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
++ WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
++}
++EXPORT_SYMBOL_GPL(sched_set_fifo);
++
++/*
++ * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
++ */
++void sched_set_fifo_low(struct task_struct *p)
++{
++ struct sched_param sp = { .sched_priority = 1 };
++ WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
++}
++EXPORT_SYMBOL_GPL(sched_set_fifo_low);
++
++void sched_set_normal(struct task_struct *p, int nice)
++{
++ struct sched_attr attr = {
++ .sched_policy = SCHED_NORMAL,
++ .sched_nice = nice,
++ };
++ WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
++}
++EXPORT_SYMBOL_GPL(sched_set_normal);
++
++static int
++do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
++{
++ struct sched_param lparam;
++
++ if (!param || pid < 0)
++ return -EINVAL;
++ if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
++ return -EFAULT;
++
++ CLASS(find_get_task, p)(pid);
++ if (!p)
++ return -ESRCH;
++
++ return sched_setscheduler(p, policy, &lparam);
++}
++
++/*
++ * Mimics kernel/events/core.c perf_copy_attr().
++ */
++static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
++{
++ u32 size;
++ int ret;
++
++ /* Zero the full structure, so that a short copy will be nice: */
++ memset(attr, 0, sizeof(*attr));
++
++ ret = get_user(size, &uattr->size);
++ if (ret)
++ return ret;
++
++ /* ABI compatibility quirk: */
++ if (!size)
++ size = SCHED_ATTR_SIZE_VER0;
++
++ if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
++ goto err_size;
++
++ ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
++ if (ret) {
++ if (ret == -E2BIG)
++ goto err_size;
++ return ret;
++ }
++
++ /*
++ * XXX: Do we want to be lenient like existing syscalls; or do we want
++ * to be strict and return an error on out-of-bounds values?
++ */
++ attr->sched_nice = clamp(attr->sched_nice, -20, 19);
++
++ /* sched/core.c uses zero here but we already know ret is zero */
++ return 0;
++
++err_size:
++ put_user(sizeof(*attr), &uattr->size);
++ return -E2BIG;
++}
++
++/**
++ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
++ * @pid: the pid in question.
++ * @policy: new policy.
++ *
++ * Return: 0 on success. An error code otherwise.
++ * @param: structure containing the new RT priority.
++ */
++SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
++{
++ if (policy < 0)
++ return -EINVAL;
++
++ return do_sched_setscheduler(pid, policy, param);
++}
++
++/**
++ * sys_sched_setparam - set/change the RT priority of a thread
++ * @pid: the pid in question.
++ * @param: structure containing the new RT priority.
++ *
++ * Return: 0 on success. An error code otherwise.
++ */
++SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
++{
++ return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
++}
++
++static void get_params(struct task_struct *p, struct sched_attr *attr)
++{
++ if (task_has_rt_policy(p))
++ attr->sched_priority = p->rt_priority;
++ else
++ attr->sched_nice = task_nice(p);
++}
++
++/**
++ * sys_sched_setattr - same as above, but with extended sched_attr
++ * @pid: the pid in question.
++ * @uattr: structure containing the extended parameters.
++ */
++SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
++ unsigned int, flags)
++{
++ struct sched_attr attr;
++ int retval;
++
++ if (!uattr || pid < 0 || flags)
++ return -EINVAL;
++
++ retval = sched_copy_attr(uattr, &attr);
++ if (retval)
++ return retval;
++
++ if ((int)attr.sched_policy < 0)
++ return -EINVAL;
++
++ CLASS(find_get_task, p)(pid);
++ if (!p)
++ return -ESRCH;
++
++ if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS)
++ get_params(p, &attr);
++
++ return sched_setattr(p, &attr);
++}
++
++/**
++ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
++ * @pid: the pid in question.
++ *
++ * Return: On success, the policy of the thread. Otherwise, a negative error
++ * code.
++ */
++SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
++{
++ struct task_struct *p;
++ int retval = -EINVAL;
++
++ if (pid < 0)
++ return -ESRCH;
++
++ guard(rcu)();
++ p = find_process_by_pid(pid);
++ if (!p)
++ return -ESRCH;
++
++ retval = security_task_getscheduler(p);
++ if (!retval)
++ retval = p->policy;
++
++ return retval;
++}
++
++/**
++ * sys_sched_getscheduler - get the RT priority of a thread
++ * @pid: the pid in question.
++ * @param: structure containing the RT priority.
++ *
++ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
++ * code.
++ */
++SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
++{
++ struct sched_param lp = { .sched_priority = 0 };
++ struct task_struct *p;
++
++ if (!param || pid < 0)
++ return -EINVAL;
++
++ scoped_guard (rcu) {
++ int retval;
++
++ p = find_process_by_pid(pid);
++ if (!p)
++ return -EINVAL;
++
++ retval = security_task_getscheduler(p);
++ if (retval)
++ return retval;
++
++ if (task_has_rt_policy(p))
++ lp.sched_priority = p->rt_priority;
++ }
++
++ /*
++ * This one might sleep, we cannot do it with a spinlock held ...
++ */
++ return copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
++}
++
++/*
++ * Copy the kernel size attribute structure (which might be larger
++ * than what user-space knows about) to user-space.
++ *
++ * Note that all cases are valid: user-space buffer can be larger or
++ * smaller than the kernel-space buffer. The usual case is that both
++ * have the same size.
++ */
++static int
++sched_attr_copy_to_user(struct sched_attr __user *uattr,
++ struct sched_attr *kattr,
++ unsigned int usize)
++{
++ unsigned int ksize = sizeof(*kattr);
++
++ if (!access_ok(uattr, usize))
++ return -EFAULT;
++
++ /*
++ * sched_getattr() ABI forwards and backwards compatibility:
++ *
++ * If usize == ksize then we just copy everything to user-space and all is good.
++ *
++ * If usize < ksize then we only copy as much as user-space has space for,
++ * this keeps ABI compatibility as well. We skip the rest.
++ *
++ * If usize > ksize then user-space is using a newer version of the ABI,
++ * which part the kernel doesn't know about. Just ignore it - tooling can
++ * detect the kernel's knowledge of attributes from the attr->size value
++ * which is set to ksize in this case.
++ */
++ kattr->size = min(usize, ksize);
++
++ if (copy_to_user(uattr, kattr, kattr->size))
++ return -EFAULT;
++
++ return 0;
++}
++
++/**
++ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
++ * @pid: the pid in question.
++ * @uattr: structure containing the extended parameters.
++ * @usize: sizeof(attr) for fwd/bwd comp.
++ * @flags: for future extension.
++ */
++SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
++ unsigned int, usize, unsigned int, flags)
++{
++ struct sched_attr kattr = { };
++ struct task_struct *p;
++ int retval;
++
++ if (!uattr || pid < 0 || usize > PAGE_SIZE ||
++ usize < SCHED_ATTR_SIZE_VER0 || flags)
++ return -EINVAL;
++
++ scoped_guard (rcu) {
++ p = find_process_by_pid(pid);
++ if (!p)
++ return -ESRCH;
++
++ retval = security_task_getscheduler(p);
++ if (retval)
++ return retval;
++
++ kattr.sched_policy = p->policy;
++ if (p->sched_reset_on_fork)
++ kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
++ get_params(p, &kattr);
++ kattr.sched_flags &= SCHED_FLAG_ALL;
++
++#ifdef CONFIG_UCLAMP_TASK
++ kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
++ kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
++#endif
++ }
++
++ return sched_attr_copy_to_user(uattr, &kattr, usize);
++}
++
++#ifdef CONFIG_SMP
++int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
++{
++ return 0;
++}
++#endif
++
++static int
++__sched_setaffinity(struct task_struct *p, struct affinity_context *ctx)
++{
++ int retval;
++ cpumask_var_t cpus_allowed, new_mask;
++
++ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
++ return -ENOMEM;
++
++ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
++ retval = -ENOMEM;
++ goto out_free_cpus_allowed;
++ }
++
++ cpuset_cpus_allowed(p, cpus_allowed);
++ cpumask_and(new_mask, ctx->new_mask, cpus_allowed);
++
++ ctx->new_mask = new_mask;
++ ctx->flags |= SCA_CHECK;
++
++ retval = __set_cpus_allowed_ptr(p, ctx);
++ if (retval)
++ goto out_free_new_mask;
++
++ cpuset_cpus_allowed(p, cpus_allowed);
++ if (!cpumask_subset(new_mask, cpus_allowed)) {
++ /*
++ * We must have raced with a concurrent cpuset
++ * update. Just reset the cpus_allowed to the
++ * cpuset's cpus_allowed
++ */
++ cpumask_copy(new_mask, cpus_allowed);
++
++ /*
++ * If SCA_USER is set, a 2nd call to __set_cpus_allowed_ptr()
++ * will restore the previous user_cpus_ptr value.
++ *
++ * In the unlikely event a previous user_cpus_ptr exists,
++ * we need to further restrict the mask to what is allowed
++ * by that old user_cpus_ptr.
++ */
++ if (unlikely((ctx->flags & SCA_USER) && ctx->user_mask)) {
++ bool empty = !cpumask_and(new_mask, new_mask,
++ ctx->user_mask);
++
++ if (WARN_ON_ONCE(empty))
++ cpumask_copy(new_mask, cpus_allowed);
++ }
++ __set_cpus_allowed_ptr(p, ctx);
++ retval = -EINVAL;
++ }
++
++out_free_new_mask:
++ free_cpumask_var(new_mask);
++out_free_cpus_allowed:
++ free_cpumask_var(cpus_allowed);
++ return retval;
++}
++
++long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
++{
++ struct affinity_context ac;
++ struct cpumask *user_mask;
++ int retval;
++
++ CLASS(find_get_task, p)(pid);
++ if (!p)
++ return -ESRCH;
++
++ if (p->flags & PF_NO_SETAFFINITY)
++ return -EINVAL;
++
++ if (!check_same_owner(p)) {
++ guard(rcu)();
++ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE))
++ return -EPERM;
++ }
++
++ retval = security_task_setscheduler(p);
++ if (retval)
++ return retval;
++
++ /*
++ * With non-SMP configs, user_cpus_ptr/user_mask isn't used and
++ * alloc_user_cpus_ptr() returns NULL.
++ */
++ user_mask = alloc_user_cpus_ptr(NUMA_NO_NODE);
++ if (user_mask) {
++ cpumask_copy(user_mask, in_mask);
++ } else if (IS_ENABLED(CONFIG_SMP)) {
++ return -ENOMEM;
++ }
++
++ ac = (struct affinity_context){
++ .new_mask = in_mask,
++ .user_mask = user_mask,
++ .flags = SCA_USER,
++ };
++
++ retval = __sched_setaffinity(p, &ac);
++ kfree(ac.user_mask);
++
++ return retval;
++}
++
++static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
++ struct cpumask *new_mask)
++{
++ if (len < cpumask_size())
++ cpumask_clear(new_mask);
++ else if (len > cpumask_size())
++ len = cpumask_size();
++
++ return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
++}
++
++/**
++ * sys_sched_setaffinity - set the CPU affinity of a process
++ * @pid: pid of the process
++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
++ * @user_mask_ptr: user-space pointer to the new CPU mask
++ *
++ * Return: 0 on success. An error code otherwise.
++ */
++SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
++ unsigned long __user *, user_mask_ptr)
++{
++ cpumask_var_t new_mask;
++ int retval;
++
++ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
++ return -ENOMEM;
++
++ retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
++ if (retval == 0)
++ retval = sched_setaffinity(pid, new_mask);
++ free_cpumask_var(new_mask);
++ return retval;
++}
++
++long sched_getaffinity(pid_t pid, cpumask_t *mask)
++{
++ struct task_struct *p;
++ int retval;
++
++ guard(rcu)();
++ p = find_process_by_pid(pid);
++ if (!p)
++ return -ESRCH;
++
++ retval = security_task_getscheduler(p);
++ if (retval)
++ return retval;
++
++ guard(raw_spinlock_irqsave)(&p->pi_lock);
++ cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
++
++ return retval;
++}
++
++/**
++ * sys_sched_getaffinity - get the CPU affinity of a process
++ * @pid: pid of the process
++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
++ * @user_mask_ptr: user-space pointer to hold the current CPU mask
++ *
++ * Return: size of CPU mask copied to user_mask_ptr on success. An
++ * error code otherwise.
++ */
++SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
++ unsigned long __user *, user_mask_ptr)
++{
++ int ret;
++ cpumask_var_t mask;
++
++ if ((len * BITS_PER_BYTE) < nr_cpu_ids)
++ return -EINVAL;
++ if (len & (sizeof(unsigned long)-1))
++ return -EINVAL;
++
++ if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
++ return -ENOMEM;
++
++ ret = sched_getaffinity(pid, mask);
++ if (ret == 0) {
++ unsigned int retlen = min(len, cpumask_size());
++
++ if (copy_to_user(user_mask_ptr, cpumask_bits(mask), retlen))
++ ret = -EFAULT;
++ else
++ ret = retlen;
++ }
++ free_cpumask_var(mask);
++
++ return ret;
++}
++
++static void do_sched_yield(void)
++{
++ struct rq *rq;
++ struct rq_flags rf;
++ struct task_struct *p;
++
++ if (!sched_yield_type)
++ return;
++
++ rq = this_rq_lock_irq(&rf);
++
++ schedstat_inc(rq->yld_count);
++
++ p = current;
++ if (rt_task(p)) {
++ if (task_on_rq_queued(p))
++ requeue_task(p, rq, task_sched_prio_idx(p, rq));
++ } else if (rq->nr_running > 1) {
++ if (1 == sched_yield_type) {
++ do_sched_yield_type_1(p, rq);
++ if (task_on_rq_queued(p))
++ requeue_task(p, rq, task_sched_prio_idx(p, rq));
++ } else if (2 == sched_yield_type) {
++ rq->skip = p;
++ }
++ }
++
++ preempt_disable();
++ raw_spin_unlock_irq(&rq->lock);
++ sched_preempt_enable_no_resched();
++
++ schedule();
++}
++
++/**
++ * sys_sched_yield - yield the current processor to other threads.
++ *
++ * This function yields the current CPU to other tasks. If there are no
++ * other threads running on this CPU then this function will return.
++ *
++ * Return: 0.
++ */
++SYSCALL_DEFINE0(sched_yield)
++{
++ do_sched_yield();
++ return 0;
++}
++
++#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
++int __sched __cond_resched(void)
++{
++ if (should_resched(0)) {
++ preempt_schedule_common();
++ return 1;
++ }
++ /*
++ * In preemptible kernels, ->rcu_read_lock_nesting tells the tick
++ * whether the current CPU is in an RCU read-side critical section,
++ * so the tick can report quiescent states even for CPUs looping
++ * in kernel context. In contrast, in non-preemptible kernels,
++ * RCU readers leave no in-memory hints, which means that CPU-bound
++ * processes executing in kernel context might never report an
++ * RCU quiescent state. Therefore, the following code causes
++ * cond_resched() to report a quiescent state, but only when RCU
++ * is in urgent need of one.
++ */
++#ifndef CONFIG_PREEMPT_RCU
++ rcu_all_qs();
++#endif
++ return 0;
++}
++EXPORT_SYMBOL(__cond_resched);
++#endif
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
++#define cond_resched_dynamic_enabled __cond_resched
++#define cond_resched_dynamic_disabled ((void *)&__static_call_return0)
++DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched);
++EXPORT_STATIC_CALL_TRAMP(cond_resched);
++
++#define might_resched_dynamic_enabled __cond_resched
++#define might_resched_dynamic_disabled ((void *)&__static_call_return0)
++DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched);
++EXPORT_STATIC_CALL_TRAMP(might_resched);
++#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
++static DEFINE_STATIC_KEY_FALSE(sk_dynamic_cond_resched);
++int __sched dynamic_cond_resched(void)
++{
++ klp_sched_try_switch();
++ if (!static_branch_unlikely(&sk_dynamic_cond_resched))
++ return 0;
++ return __cond_resched();
++}
++EXPORT_SYMBOL(dynamic_cond_resched);
++
++static DEFINE_STATIC_KEY_FALSE(sk_dynamic_might_resched);
++int __sched dynamic_might_resched(void)
++{
++ if (!static_branch_unlikely(&sk_dynamic_might_resched))
++ return 0;
++ return __cond_resched();
++}
++EXPORT_SYMBOL(dynamic_might_resched);
++#endif
++#endif
++
++/*
++ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
++ * call schedule, and on return reacquire the lock.
++ *
++ * This works OK both with and without CONFIG_PREEMPTION. We do strange low-level
++ * operations here to prevent schedule() from being called twice (once via
++ * spin_unlock(), once by hand).
++ */
++int __cond_resched_lock(spinlock_t *lock)
++{
++ int resched = should_resched(PREEMPT_LOCK_OFFSET);
++ int ret = 0;
++
++ lockdep_assert_held(lock);
++
++ if (spin_needbreak(lock) || resched) {
++ spin_unlock(lock);
++ if (!_cond_resched())
++ cpu_relax();
++ ret = 1;
++ spin_lock(lock);
++ }
++ return ret;
++}
++EXPORT_SYMBOL(__cond_resched_lock);
++
++int __cond_resched_rwlock_read(rwlock_t *lock)
++{
++ int resched = should_resched(PREEMPT_LOCK_OFFSET);
++ int ret = 0;
++
++ lockdep_assert_held_read(lock);
++
++ if (rwlock_needbreak(lock) || resched) {
++ read_unlock(lock);
++ if (!_cond_resched())
++ cpu_relax();
++ ret = 1;
++ read_lock(lock);
++ }
++ return ret;
++}
++EXPORT_SYMBOL(__cond_resched_rwlock_read);
++
++int __cond_resched_rwlock_write(rwlock_t *lock)
++{
++ int resched = should_resched(PREEMPT_LOCK_OFFSET);
++ int ret = 0;
++
++ lockdep_assert_held_write(lock);
++
++ if (rwlock_needbreak(lock) || resched) {
++ write_unlock(lock);
++ if (!_cond_resched())
++ cpu_relax();
++ ret = 1;
++ write_lock(lock);
++ }
++ return ret;
++}
++EXPORT_SYMBOL(__cond_resched_rwlock_write);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++
++#ifdef CONFIG_GENERIC_ENTRY
++#include <linux/entry-common.h>
++#endif
++
++/*
++ * SC:cond_resched
++ * SC:might_resched
++ * SC:preempt_schedule
++ * SC:preempt_schedule_notrace
++ * SC:irqentry_exit_cond_resched
++ *
++ *
++ * NONE:
++ * cond_resched <- __cond_resched
++ * might_resched <- RET0
++ * preempt_schedule <- NOP
++ * preempt_schedule_notrace <- NOP
++ * irqentry_exit_cond_resched <- NOP
++ *
++ * VOLUNTARY:
++ * cond_resched <- __cond_resched
++ * might_resched <- __cond_resched
++ * preempt_schedule <- NOP
++ * preempt_schedule_notrace <- NOP
++ * irqentry_exit_cond_resched <- NOP
++ *
++ * FULL:
++ * cond_resched <- RET0
++ * might_resched <- RET0
++ * preempt_schedule <- preempt_schedule
++ * preempt_schedule_notrace <- preempt_schedule_notrace
++ * irqentry_exit_cond_resched <- irqentry_exit_cond_resched
++ */
++
++enum {
++ preempt_dynamic_undefined = -1,
++ preempt_dynamic_none,
++ preempt_dynamic_voluntary,
++ preempt_dynamic_full,
++};
++
++int preempt_dynamic_mode = preempt_dynamic_undefined;
++
++int sched_dynamic_mode(const char *str)
++{
++ if (!strcmp(str, "none"))
++ return preempt_dynamic_none;
++
++ if (!strcmp(str, "voluntary"))
++ return preempt_dynamic_voluntary;
++
++ if (!strcmp(str, "full"))
++ return preempt_dynamic_full;
++
++ return -EINVAL;
++}
++
++#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
++#define preempt_dynamic_enable(f) static_call_update(f, f##_dynamic_enabled)
++#define preempt_dynamic_disable(f) static_call_update(f, f##_dynamic_disabled)
++#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
++#define preempt_dynamic_enable(f) static_key_enable(&sk_dynamic_##f.key)
++#define preempt_dynamic_disable(f) static_key_disable(&sk_dynamic_##f.key)
++#else
++#error "Unsupported PREEMPT_DYNAMIC mechanism"
++#endif
++
++static DEFINE_MUTEX(sched_dynamic_mutex);
++static bool klp_override;
++
++static void __sched_dynamic_update(int mode)
++{
++ /*
++ * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in
++ * the ZERO state, which is invalid.
++ */
++ if (!klp_override)
++ preempt_dynamic_enable(cond_resched);
++ preempt_dynamic_enable(cond_resched);
++ preempt_dynamic_enable(might_resched);
++ preempt_dynamic_enable(preempt_schedule);
++ preempt_dynamic_enable(preempt_schedule_notrace);
++ preempt_dynamic_enable(irqentry_exit_cond_resched);
++
++ switch (mode) {
++ case preempt_dynamic_none:
++ if (!klp_override)
++ preempt_dynamic_enable(cond_resched);
++ preempt_dynamic_disable(might_resched);
++ preempt_dynamic_disable(preempt_schedule);
++ preempt_dynamic_disable(preempt_schedule_notrace);
++ preempt_dynamic_disable(irqentry_exit_cond_resched);
++ if (mode != preempt_dynamic_mode)
++ pr_info("Dynamic Preempt: none\n");
++ break;
++
++ case preempt_dynamic_voluntary:
++ if (!klp_override)
++ preempt_dynamic_enable(cond_resched);
++ preempt_dynamic_enable(might_resched);
++ preempt_dynamic_disable(preempt_schedule);
++ preempt_dynamic_disable(preempt_schedule_notrace);
++ preempt_dynamic_disable(irqentry_exit_cond_resched);
++ if (mode != preempt_dynamic_mode)
++ pr_info("Dynamic Preempt: voluntary\n");
++ break;
++
++ case preempt_dynamic_full:
++ if (!klp_override)
++ preempt_dynamic_enable(cond_resched);
++ preempt_dynamic_disable(might_resched);
++ preempt_dynamic_enable(preempt_schedule);
++ preempt_dynamic_enable(preempt_schedule_notrace);
++ preempt_dynamic_enable(irqentry_exit_cond_resched);
++ if (mode != preempt_dynamic_mode)
++ pr_info("Dynamic Preempt: full\n");
++ break;
++ }
++
++ preempt_dynamic_mode = mode;
++}
++
++void sched_dynamic_update(int mode)
++{
++ mutex_lock(&sched_dynamic_mutex);
++ __sched_dynamic_update(mode);
++ mutex_unlock(&sched_dynamic_mutex);
++}
++
++#ifdef CONFIG_HAVE_PREEMPT_DYNAMIC_CALL
++
++static int klp_cond_resched(void)
++{
++ __klp_sched_try_switch();
++ return __cond_resched();
++}
++
++void sched_dynamic_klp_enable(void)
++{
++ mutex_lock(&sched_dynamic_mutex);
++
++ klp_override = true;
++ static_call_update(cond_resched, klp_cond_resched);
++
++ mutex_unlock(&sched_dynamic_mutex);
++}
++
++void sched_dynamic_klp_disable(void)
++{
++ mutex_lock(&sched_dynamic_mutex);
++
++ klp_override = false;
++ __sched_dynamic_update(preempt_dynamic_mode);
++
++ mutex_unlock(&sched_dynamic_mutex);
++}
++
++#endif /* CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */
++
++
++static int __init setup_preempt_mode(char *str)
++{
++ int mode = sched_dynamic_mode(str);
++ if (mode < 0) {
++ pr_warn("Dynamic Preempt: unsupported mode: %s\n", str);
++ return 0;
++ }
++
++ sched_dynamic_update(mode);
++ return 1;
++}
++__setup("preempt=", setup_preempt_mode);
++
++static void __init preempt_dynamic_init(void)
++{
++ if (preempt_dynamic_mode == preempt_dynamic_undefined) {
++ if (IS_ENABLED(CONFIG_PREEMPT_NONE)) {
++ sched_dynamic_update(preempt_dynamic_none);
++ } else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY)) {
++ sched_dynamic_update(preempt_dynamic_voluntary);
++ } else {
++ /* Default static call setting, nothing to do */
++ WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT));
++ preempt_dynamic_mode = preempt_dynamic_full;
++ pr_info("Dynamic Preempt: full\n");
++ }
++ }
++}
++
++#define PREEMPT_MODEL_ACCESSOR(mode) \
++ bool preempt_model_##mode(void) \
++ { \
++ WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \
++ return preempt_dynamic_mode == preempt_dynamic_##mode; \
++ } \
++ EXPORT_SYMBOL_GPL(preempt_model_##mode)
++
++PREEMPT_MODEL_ACCESSOR(none);
++PREEMPT_MODEL_ACCESSOR(voluntary);
++PREEMPT_MODEL_ACCESSOR(full);
++
++#else /* !CONFIG_PREEMPT_DYNAMIC */
++
++static inline void preempt_dynamic_init(void) { }
++
++#endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */
++
++/**
++ * yield - yield the current processor to other threads.
++ *
++ * Do not ever use this function, there's a 99% chance you're doing it wrong.
++ *
++ * The scheduler is at all times free to pick the calling task as the most
++ * eligible task to run, if removing the yield() call from your code breaks
++ * it, it's already broken.
++ *
++ * Typical broken usage is:
++ *
++ * while (!event)
++ * yield();
++ *
++ * where one assumes that yield() will let 'the other' process run that will
++ * make event true. If the current task is a SCHED_FIFO task that will never
++ * happen. Never use yield() as a progress guarantee!!
++ *
++ * If you want to use yield() to wait for something, use wait_event().
++ * If you want to use yield() to be 'nice' for others, use cond_resched().
++ * If you still want to use yield(), do not!
++ */
++void __sched yield(void)
++{
++ set_current_state(TASK_RUNNING);
++ do_sched_yield();
++}
++EXPORT_SYMBOL(yield);
++
++/**
++ * yield_to - yield the current processor to another thread in
++ * your thread group, or accelerate that thread toward the
++ * processor it's on.
++ * @p: target task
++ * @preempt: whether task preemption is allowed or not
++ *
++ * It's the caller's job to ensure that the target task struct
++ * can't go away on us before we can do any checks.
++ *
++ * In Alt schedule FW, yield_to is not supported.
++ *
++ * Return:
++ * true (>0) if we indeed boosted the target task.
++ * false (0) if we failed to boost the target.
++ * -ESRCH if there's no task to yield to.
++ */
++int __sched yield_to(struct task_struct *p, bool preempt)
++{
++ return 0;
++}
++EXPORT_SYMBOL_GPL(yield_to);
++
++int io_schedule_prepare(void)
++{
++ int old_iowait = current->in_iowait;
++
++ current->in_iowait = 1;
++ blk_flush_plug(current->plug, true);
++ return old_iowait;
++}
++
++void io_schedule_finish(int token)
++{
++ current->in_iowait = token;
++}
++
++/*
++ * This task is about to go to sleep on IO. Increment rq->nr_iowait so
++ * that process accounting knows that this is a task in IO wait state.
++ *
++ * But don't do that if it is a deliberate, throttling IO wait (this task
++ * has set its backing_dev_info: the queue against which it should throttle)
++ */
++
++long __sched io_schedule_timeout(long timeout)
++{
++ int token;
++ long ret;
++
++ token = io_schedule_prepare();
++ ret = schedule_timeout(timeout);
++ io_schedule_finish(token);
++
++ return ret;
++}
++EXPORT_SYMBOL(io_schedule_timeout);
++
++void __sched io_schedule(void)
++{
++ int token;
++
++ token = io_schedule_prepare();
++ schedule();
++ io_schedule_finish(token);
++}
++EXPORT_SYMBOL(io_schedule);
++
++/**
++ * sys_sched_get_priority_max - return maximum RT priority.
++ * @policy: scheduling class.
++ *
++ * Return: On success, this syscall returns the maximum
++ * rt_priority that can be used by a given scheduling class.
++ * On failure, a negative error code is returned.
++ */
++SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
++{
++ int ret = -EINVAL;
++
++ switch (policy) {
++ case SCHED_FIFO:
++ case SCHED_RR:
++ ret = MAX_RT_PRIO - 1;
++ break;
++ case SCHED_NORMAL:
++ case SCHED_BATCH:
++ case SCHED_IDLE:
++ ret = 0;
++ break;
++ }
++ return ret;
++}
++
++/**
++ * sys_sched_get_priority_min - return minimum RT priority.
++ * @policy: scheduling class.
++ *
++ * Return: On success, this syscall returns the minimum
++ * rt_priority that can be used by a given scheduling class.
++ * On failure, a negative error code is returned.
++ */
++SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
++{
++ int ret = -EINVAL;
++
++ switch (policy) {
++ case SCHED_FIFO:
++ case SCHED_RR:
++ ret = 1;
++ break;
++ case SCHED_NORMAL:
++ case SCHED_BATCH:
++ case SCHED_IDLE:
++ ret = 0;
++ break;
++ }
++ return ret;
++}
++
++static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
++{
++ struct task_struct *p;
++ int retval;
++
++ alt_sched_debug();
++
++ if (pid < 0)
++ return -EINVAL;
++
++ guard(rcu)();
++ p = find_process_by_pid(pid);
++ if (!p)
++ return -EINVAL;
++
++ retval = security_task_getscheduler(p);
++ if (retval)
++ return retval;
++
++ *t = ns_to_timespec64(sysctl_sched_base_slice);
++ return 0;
++}
++
++/**
++ * sys_sched_rr_get_interval - return the default timeslice of a process.
++ * @pid: pid of the process.
++ * @interval: userspace pointer to the timeslice value.
++ *
++ *
++ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
++ * an error code.
++ */
++SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
++ struct __kernel_timespec __user *, interval)
++{
++ struct timespec64 t;
++ int retval = sched_rr_get_interval(pid, &t);
++
++ if (retval == 0)
++ retval = put_timespec64(&t, interval);
++
++ return retval;
++}
++
++#ifdef CONFIG_COMPAT_32BIT_TIME
++SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
++ struct old_timespec32 __user *, interval)
++{
++ struct timespec64 t;
++ int retval = sched_rr_get_interval(pid, &t);
++
++ if (retval == 0)
++ retval = put_old_timespec32(&t, interval);
++ return retval;
++}
++#endif
++
++void sched_show_task(struct task_struct *p)
++{
++ unsigned long free = 0;
++ int ppid;
++
++ if (!try_get_task_stack(p))
++ return;
++
++ pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
++
++ if (task_is_running(p))
++ pr_cont(" running task ");
++#ifdef CONFIG_DEBUG_STACK_USAGE
++ free = stack_not_used(p);
++#endif
++ ppid = 0;
++ rcu_read_lock();
++ if (pid_alive(p))
++ ppid = task_pid_nr(rcu_dereference(p->real_parent));
++ rcu_read_unlock();
++ pr_cont(" stack:%-5lu pid:%-5d tgid:%-5d ppid:%-6d flags:0x%08lx\n",
++ free, task_pid_nr(p), task_tgid_nr(p),
++ ppid, read_task_thread_flags(p));
++
++ print_worker_info(KERN_INFO, p);
++ print_stop_info(KERN_INFO, p);
++ show_stack(p, NULL, KERN_INFO);
++ put_task_stack(p);
++}
++EXPORT_SYMBOL_GPL(sched_show_task);
++
++static inline bool
++state_filter_match(unsigned long state_filter, struct task_struct *p)
++{
++ unsigned int state = READ_ONCE(p->__state);
++
++ /* no filter, everything matches */
++ if (!state_filter)
++ return true;
++
++ /* filter, but doesn't match */
++ if (!(state & state_filter))
++ return false;
++
++ /*
++ * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
++ * TASK_KILLABLE).
++ */
++ if (state_filter == TASK_UNINTERRUPTIBLE && (state & TASK_NOLOAD))
++ return false;
++
++ return true;
++}
++
++
++void show_state_filter(unsigned int state_filter)
++{
++ struct task_struct *g, *p;
++
++ rcu_read_lock();
++ for_each_process_thread(g, p) {
++ /*
++ * reset the NMI-timeout, listing all files on a slow
++ * console might take a lot of time:
++ * Also, reset softlockup watchdogs on all CPUs, because
++ * another CPU might be blocked waiting for us to process
++ * an IPI.
++ */
++ touch_nmi_watchdog();
++ touch_all_softlockup_watchdogs();
++ if (state_filter_match(state_filter, p))
++ sched_show_task(p);
++ }
++
++#ifdef CONFIG_SCHED_DEBUG
++ /* TODO: Alt schedule FW should support this
++ if (!state_filter)
++ sysrq_sched_debug_show();
++ */
++#endif
++ rcu_read_unlock();
++ /*
++ * Only show locks if all tasks are dumped:
++ */
++ if (!state_filter)
++ debug_show_all_locks();
++}
++
++void dump_cpu_task(int cpu)
++{
++ if (cpu == smp_processor_id() && in_hardirq()) {
++ struct pt_regs *regs;
++
++ regs = get_irq_regs();
++ if (regs) {
++ show_regs(regs);
++ return;
++ }
++ }
++
++ if (trigger_single_cpu_backtrace(cpu))
++ return;
++
++ pr_info("Task dump for CPU %d:\n", cpu);
++ sched_show_task(cpu_curr(cpu));
++}
++
++/**
++ * init_idle - set up an idle thread for a given CPU
++ * @idle: task in question
++ * @cpu: CPU the idle task belongs to
++ *
++ * NOTE: this function does not set the idle thread's NEED_RESCHED
++ * flag, to make booting more robust.
++ */
++void __init init_idle(struct task_struct *idle, int cpu)
++{
++#ifdef CONFIG_SMP
++ struct affinity_context ac = (struct affinity_context) {
++ .new_mask = cpumask_of(cpu),
++ .flags = 0,
++ };
++#endif
++ struct rq *rq = cpu_rq(cpu);
++ unsigned long flags;
++
++ __sched_fork(0, idle);
++
++ raw_spin_lock_irqsave(&idle->pi_lock, flags);
++ raw_spin_lock(&rq->lock);
++
++ idle->last_ran = rq->clock_task;
++ idle->__state = TASK_RUNNING;
++ /*
++ * PF_KTHREAD should already be set at this point; regardless, make it
++ * look like a proper per-CPU kthread.
++ */
++ idle->flags |= PF_KTHREAD | PF_NO_SETAFFINITY;
++ kthread_set_per_cpu(idle, cpu);
++
++ sched_queue_init_idle(&rq->queue, idle);
++
++#ifdef CONFIG_SMP
++ /*
++ * It's possible that init_idle() gets called multiple times on a task,
++ * in that case do_set_cpus_allowed() will not do the right thing.
++ *
++ * And since this is boot we can forgo the serialisation.
++ */
++ set_cpus_allowed_common(idle, &ac);
++#endif
++
++ /* Silence PROVE_RCU */
++ rcu_read_lock();
++ __set_task_cpu(idle, cpu);
++ rcu_read_unlock();
++
++ rq->idle = idle;
++ rcu_assign_pointer(rq->curr, idle);
++ idle->on_cpu = 1;
++
++ raw_spin_unlock(&rq->lock);
++ raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
++
++ /* Set the preempt count _outside_ the spinlocks! */
++ init_idle_preempt_count(idle, cpu);
++
++ ftrace_graph_init_idle_task(idle, cpu);
++ vtime_init_idle(idle, cpu);
++#ifdef CONFIG_SMP
++ sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
++#endif
++}
++
++#ifdef CONFIG_SMP
++
++int cpuset_cpumask_can_shrink(const struct cpumask __maybe_unused *cur,
++ const struct cpumask __maybe_unused *trial)
++{
++ return 1;
++}
++
++int task_can_attach(struct task_struct *p)
++{
++ int ret = 0;
++
++ /*
++ * Kthreads which disallow setaffinity shouldn't be moved
++ * to a new cpuset; we don't want to change their CPU
++ * affinity and isolating such threads by their set of
++ * allowed nodes is unnecessary. Thus, cpusets are not
++ * applicable for such threads. This prevents checking for
++ * success of set_cpus_allowed_ptr() on all attached tasks
++ * before cpus_mask may be changed.
++ */
++ if (p->flags & PF_NO_SETAFFINITY)
++ ret = -EINVAL;
++
++ return ret;
++}
++
++bool sched_smp_initialized __read_mostly;
++
++#ifdef CONFIG_HOTPLUG_CPU
++/*
++ * Ensures that the idle task is using init_mm right before its CPU goes
++ * offline.
++ */
++void idle_task_exit(void)
++{
++ struct mm_struct *mm = current->active_mm;
++
++ BUG_ON(current != this_rq()->idle);
++
++ if (mm != &init_mm) {
++ switch_mm(mm, &init_mm, current);
++ finish_arch_post_lock_switch();
++ }
++
++ /* finish_cpu(), as ran on the BP, will clean up the active_mm state */
++}
++
++static int __balance_push_cpu_stop(void *arg)
++{
++ struct task_struct *p = arg;
++ struct rq *rq = this_rq();
++ struct rq_flags rf;
++ int cpu;
++
++ raw_spin_lock_irq(&p->pi_lock);
++ rq_lock(rq, &rf);
++
++ update_rq_clock(rq);
++
++ if (task_rq(p) == rq && task_on_rq_queued(p)) {
++ cpu = select_fallback_rq(rq->cpu, p);
++ rq = __migrate_task(rq, p, cpu);
++ }
++
++ rq_unlock(rq, &rf);
++ raw_spin_unlock_irq(&p->pi_lock);
++
++ put_task_struct(p);
++
++ return 0;
++}
++
++static DEFINE_PER_CPU(struct cpu_stop_work, push_work);
++
++/*
++ * This is enabled below SCHED_AP_ACTIVE; when !cpu_active(), but only
++ * effective when the hotplug motion is down.
++ */
++static void balance_push(struct rq *rq)
++{
++ struct task_struct *push_task = rq->curr;
++
++ lockdep_assert_held(&rq->lock);
++
++ /*
++ * Ensure the thing is persistent until balance_push_set(.on = false);
++ */
++ rq->balance_callback = &balance_push_callback;
++
++ /*
++ * Only active while going offline and when invoked on the outgoing
++ * CPU.
++ */
++ if (!cpu_dying(rq->cpu) || rq != this_rq())
++ return;
++
++ /*
++ * Both the cpu-hotplug and stop task are in this case and are
++ * required to complete the hotplug process.
++ */
++ if (kthread_is_per_cpu(push_task) ||
++ is_migration_disabled(push_task)) {
++
++ /*
++ * If this is the idle task on the outgoing CPU try to wake
++ * up the hotplug control thread which might wait for the
++ * last task to vanish. The rcuwait_active() check is
++ * accurate here because the waiter is pinned on this CPU
++ * and can't obviously be running in parallel.
++ *
++ * On RT kernels this also has to check whether there are
++ * pinned and scheduled out tasks on the runqueue. They
++ * need to leave the migrate disabled section first.
++ */
++ if (!rq->nr_running && !rq_has_pinned_tasks(rq) &&
++ rcuwait_active(&rq->hotplug_wait)) {
++ raw_spin_unlock(&rq->lock);
++ rcuwait_wake_up(&rq->hotplug_wait);
++ raw_spin_lock(&rq->lock);
++ }
++ return;
++ }
++
++ get_task_struct(push_task);
++ /*
++ * Temporarily drop rq->lock such that we can wake-up the stop task.
++ * Both preemption and IRQs are still disabled.
++ */
++ preempt_disable();
++ raw_spin_unlock(&rq->lock);
++ stop_one_cpu_nowait(rq->cpu, __balance_push_cpu_stop, push_task,
++ this_cpu_ptr(&push_work));
++ preempt_enable();
++ /*
++ * At this point need_resched() is true and we'll take the loop in
++ * schedule(). The next pick is obviously going to be the stop task
++ * which kthread_is_per_cpu() and will push this task away.
++ */
++ raw_spin_lock(&rq->lock);
++}
++
++static void balance_push_set(int cpu, bool on)
++{
++ struct rq *rq = cpu_rq(cpu);
++ struct rq_flags rf;
++
++ rq_lock_irqsave(rq, &rf);
++ if (on) {
++ WARN_ON_ONCE(rq->balance_callback);
++ rq->balance_callback = &balance_push_callback;
++ } else if (rq->balance_callback == &balance_push_callback) {
++ rq->balance_callback = NULL;
++ }
++ rq_unlock_irqrestore(rq, &rf);
++}
++
++/*
++ * Invoked from a CPUs hotplug control thread after the CPU has been marked
++ * inactive. All tasks which are not per CPU kernel threads are either
++ * pushed off this CPU now via balance_push() or placed on a different CPU
++ * during wakeup. Wait until the CPU is quiescent.
++ */
++static void balance_hotplug_wait(void)
++{
++ struct rq *rq = this_rq();
++
++ rcuwait_wait_event(&rq->hotplug_wait,
++ rq->nr_running == 1 && !rq_has_pinned_tasks(rq),
++ TASK_UNINTERRUPTIBLE);
++}
++
++#else
++
++static void balance_push(struct rq *rq)
++{
++}
++
++static void balance_push_set(int cpu, bool on)
++{
++}
++
++static inline void balance_hotplug_wait(void)
++{
++}
++#endif /* CONFIG_HOTPLUG_CPU */
++
++static void set_rq_offline(struct rq *rq)
++{
++ if (rq->online) {
++ update_rq_clock(rq);
++ rq->online = false;
++ }
++}
++
++static void set_rq_online(struct rq *rq)
++{
++ if (!rq->online)
++ rq->online = true;
++}
++
++/*
++ * used to mark begin/end of suspend/resume:
++ */
++static int num_cpus_frozen;
++
++/*
++ * Update cpusets according to cpu_active mask. If cpusets are
++ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
++ * around partition_sched_domains().
++ *
++ * If we come here as part of a suspend/resume, don't touch cpusets because we
++ * want to restore it back to its original state upon resume anyway.
++ */
++static void cpuset_cpu_active(void)
++{
++ if (cpuhp_tasks_frozen) {
++ /*
++ * num_cpus_frozen tracks how many CPUs are involved in suspend
++ * resume sequence. As long as this is not the last online
++ * operation in the resume sequence, just build a single sched
++ * domain, ignoring cpusets.
++ */
++ partition_sched_domains(1, NULL, NULL);
++ if (--num_cpus_frozen)
++ return;
++ /*
++ * This is the last CPU online operation. So fall through and
++ * restore the original sched domains by considering the
++ * cpuset configurations.
++ */
++ cpuset_force_rebuild();
++ }
++
++ cpuset_update_active_cpus();
++}
++
++static int cpuset_cpu_inactive(unsigned int cpu)
++{
++ if (!cpuhp_tasks_frozen) {
++ cpuset_update_active_cpus();
++ } else {
++ num_cpus_frozen++;
++ partition_sched_domains(1, NULL, NULL);
++ }
++ return 0;
++}
++
++int sched_cpu_activate(unsigned int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++ unsigned long flags;
++
++ /*
++ * Clear the balance_push callback and prepare to schedule
++ * regular tasks.
++ */
++ balance_push_set(cpu, false);
++
++#ifdef CONFIG_SCHED_SMT
++ /*
++ * When going up, increment the number of cores with SMT present.
++ */
++ if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
++ static_branch_inc_cpuslocked(&sched_smt_present);
++#endif
++ set_cpu_active(cpu, true);
++
++ if (sched_smp_initialized)
++ cpuset_cpu_active();
++
++ /*
++ * Put the rq online, if not already. This happens:
++ *
++ * 1) In the early boot process, because we build the real domains
++ * after all cpus have been brought up.
++ *
++ * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
++ * domains.
++ */
++ raw_spin_lock_irqsave(&rq->lock, flags);
++ set_rq_online(rq);
++ raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++ return 0;
++}
++
++int sched_cpu_deactivate(unsigned int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++ unsigned long flags;
++ int ret;
++
++ set_cpu_active(cpu, false);
++
++ /*
++ * From this point forward, this CPU will refuse to run any task that
++ * is not: migrate_disable() or KTHREAD_IS_PER_CPU, and will actively
++ * push those tasks away until this gets cleared, see
++ * sched_cpu_dying().
++ */
++ balance_push_set(cpu, true);
++
++ /*
++ * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
++ * users of this state to go away such that all new such users will
++ * observe it.
++ *
++ * Specifically, we rely on ttwu to no longer target this CPU, see
++ * ttwu_queue_cond() and is_cpu_allowed().
++ *
++ * Do sync before park smpboot threads to take care the rcu boost case.
++ */
++ synchronize_rcu();
++
++ raw_spin_lock_irqsave(&rq->lock, flags);
++ set_rq_offline(rq);
++ raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++#ifdef CONFIG_SCHED_SMT
++ /*
++ * When going down, decrement the number of cores with SMT present.
++ */
++ if (cpumask_weight(cpu_smt_mask(cpu)) == 2) {
++ static_branch_dec_cpuslocked(&sched_smt_present);
++ if (!static_branch_likely(&sched_smt_present))
++ cpumask_clear(&sched_sg_idle_mask);
++ }
++#endif
++
++ if (!sched_smp_initialized)
++ return 0;
++
++ ret = cpuset_cpu_inactive(cpu);
++ if (ret) {
++ balance_push_set(cpu, false);
++ set_cpu_active(cpu, true);
++ return ret;
++ }
++
++ return 0;
++}
++
++static void sched_rq_cpu_starting(unsigned int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++
++ rq->calc_load_update = calc_load_update;
++}
++
++int sched_cpu_starting(unsigned int cpu)
++{
++ sched_rq_cpu_starting(cpu);
++ sched_tick_start(cpu);
++ return 0;
++}
++
++#ifdef CONFIG_HOTPLUG_CPU
++
++/*
++ * Invoked immediately before the stopper thread is invoked to bring the
++ * CPU down completely. At this point all per CPU kthreads except the
++ * hotplug thread (current) and the stopper thread (inactive) have been
++ * either parked or have been unbound from the outgoing CPU. Ensure that
++ * any of those which might be on the way out are gone.
++ *
++ * If after this point a bound task is being woken on this CPU then the
++ * responsible hotplug callback has failed to do it's job.
++ * sched_cpu_dying() will catch it with the appropriate fireworks.
++ */
++int sched_cpu_wait_empty(unsigned int cpu)
++{
++ balance_hotplug_wait();
++ return 0;
++}
++
++/*
++ * Since this CPU is going 'away' for a while, fold any nr_active delta we
++ * might have. Called from the CPU stopper task after ensuring that the
++ * stopper is the last running task on the CPU, so nr_active count is
++ * stable. We need to take the teardown thread which is calling this into
++ * account, so we hand in adjust = 1 to the load calculation.
++ *
++ * Also see the comment "Global load-average calculations".
++ */
++static void calc_load_migrate(struct rq *rq)
++{
++ long delta = calc_load_fold_active(rq, 1);
++
++ if (delta)
++ atomic_long_add(delta, &calc_load_tasks);
++}
++
++static void dump_rq_tasks(struct rq *rq, const char *loglvl)
++{
++ struct task_struct *g, *p;
++ int cpu = cpu_of(rq);
++
++ lockdep_assert_held(&rq->lock);
++
++ printk("%sCPU%d enqueued tasks (%u total):\n", loglvl, cpu, rq->nr_running);
++ for_each_process_thread(g, p) {
++ if (task_cpu(p) != cpu)
++ continue;
++
++ if (!task_on_rq_queued(p))
++ continue;
++
++ printk("%s\tpid: %d, name: %s\n", loglvl, p->pid, p->comm);
++ }
++}
++
++int sched_cpu_dying(unsigned int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++ unsigned long flags;
++
++ /* Handle pending wakeups and then migrate everything off */
++ sched_tick_stop(cpu);
++
++ raw_spin_lock_irqsave(&rq->lock, flags);
++ if (rq->nr_running != 1 || rq_has_pinned_tasks(rq)) {
++ WARN(true, "Dying CPU not properly vacated!");
++ dump_rq_tasks(rq, KERN_WARNING);
++ }
++ raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++ calc_load_migrate(rq);
++ hrtick_clear(rq);
++ return 0;
++}
++#endif
++
++#ifdef CONFIG_SMP
++static void sched_init_topology_cpumask_early(void)
++{
++ int cpu;
++ cpumask_t *tmp;
++
++ for_each_possible_cpu(cpu) {
++ /* init topo masks */
++ tmp = per_cpu(sched_cpu_topo_masks, cpu);
++
++ cpumask_copy(tmp, cpumask_of(cpu));
++ tmp++;
++ cpumask_copy(tmp, cpu_possible_mask);
++ per_cpu(sched_cpu_llc_mask, cpu) = tmp;
++ per_cpu(sched_cpu_topo_end_mask, cpu) = ++tmp;
++ /*per_cpu(sd_llc_id, cpu) = cpu;*/
++ }
++}
++
++#define TOPOLOGY_CPUMASK(name, mask, last)\
++ if (cpumask_and(topo, topo, mask)) { \
++ cpumask_copy(topo, mask); \
++ printk(KERN_INFO "sched: cpu#%02d topo: 0x%08lx - "#name, \
++ cpu, (topo++)->bits[0]); \
++ } \
++ if (!last) \
++ bitmap_complement(cpumask_bits(topo), cpumask_bits(mask), \
++ nr_cpumask_bits);
++
++static void sched_init_topology_cpumask(void)
++{
++ int cpu;
++ cpumask_t *topo;
++
++ for_each_online_cpu(cpu) {
++ /* take chance to reset time slice for idle tasks */
++ cpu_rq(cpu)->idle->time_slice = sysctl_sched_base_slice;
++
++ topo = per_cpu(sched_cpu_topo_masks, cpu) + 1;
++
++ bitmap_complement(cpumask_bits(topo), cpumask_bits(cpumask_of(cpu)),
++ nr_cpumask_bits);
++#ifdef CONFIG_SCHED_SMT
++ TOPOLOGY_CPUMASK(smt, topology_sibling_cpumask(cpu), false);
++#endif
++ per_cpu(sd_llc_id, cpu) = cpumask_first(cpu_coregroup_mask(cpu));
++ per_cpu(sched_cpu_llc_mask, cpu) = topo;
++ TOPOLOGY_CPUMASK(coregroup, cpu_coregroup_mask(cpu), false);
++
++ TOPOLOGY_CPUMASK(core, topology_core_cpumask(cpu), false);
++
++ TOPOLOGY_CPUMASK(others, cpu_online_mask, true);
++
++ per_cpu(sched_cpu_topo_end_mask, cpu) = topo;
++ printk(KERN_INFO "sched: cpu#%02d llc_id = %d, llc_mask idx = %d\n",
++ cpu, per_cpu(sd_llc_id, cpu),
++ (int) (per_cpu(sched_cpu_llc_mask, cpu) -
++ per_cpu(sched_cpu_topo_masks, cpu)));
++ }
++}
++#endif
++
++void __init sched_init_smp(void)
++{
++ /* Move init over to a non-isolated CPU */
++ if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0)
++ BUG();
++ current->flags &= ~PF_NO_SETAFFINITY;
++
++ sched_init_topology_cpumask();
++
++ sched_smp_initialized = true;
++}
++
++static int __init migration_init(void)
++{
++ sched_cpu_starting(smp_processor_id());
++ return 0;
++}
++early_initcall(migration_init);
++
++#else
++void __init sched_init_smp(void)
++{
++ cpu_rq(0)->idle->time_slice = sysctl_sched_base_slice;
++}
++#endif /* CONFIG_SMP */
++
++int in_sched_functions(unsigned long addr)
++{
++ return in_lock_functions(addr) ||
++ (addr >= (unsigned long)__sched_text_start
++ && addr < (unsigned long)__sched_text_end);
++}
++
++#ifdef CONFIG_CGROUP_SCHED
++/* task group related information */
++struct task_group {
++ struct cgroup_subsys_state css;
++
++ struct rcu_head rcu;
++ struct list_head list;
++
++ struct task_group *parent;
++ struct list_head siblings;
++ struct list_head children;
++#ifdef CONFIG_FAIR_GROUP_SCHED
++ unsigned long shares;
++#endif
++};
++
++/*
++ * Default task group.
++ * Every task in system belongs to this group at bootup.
++ */
++struct task_group root_task_group;
++LIST_HEAD(task_groups);
++
++/* Cacheline aligned slab cache for task_group */
++static struct kmem_cache *task_group_cache __ro_after_init;
++#endif /* CONFIG_CGROUP_SCHED */
++
++void __init sched_init(void)
++{
++ int i;
++ struct rq *rq;
++
++ printk(KERN_INFO "sched/alt: "ALT_SCHED_NAME" CPU Scheduler "ALT_SCHED_VERSION\
++ " by Alfred Chen.\n");
++
++ wait_bit_init();
++
++#ifdef CONFIG_SMP
++ for (i = 0; i < SCHED_QUEUE_BITS; i++)
++ cpumask_copy(sched_preempt_mask + i, cpu_present_mask);
++#endif
++
++#ifdef CONFIG_CGROUP_SCHED
++ task_group_cache = KMEM_CACHE(task_group, 0);
++
++ list_add(&root_task_group.list, &task_groups);
++ INIT_LIST_HEAD(&root_task_group.children);
++ INIT_LIST_HEAD(&root_task_group.siblings);
++#endif /* CONFIG_CGROUP_SCHED */
++ for_each_possible_cpu(i) {
++ rq = cpu_rq(i);
++
++ sched_queue_init(&rq->queue);
++ rq->prio = IDLE_TASK_SCHED_PRIO;
++ rq->skip = NULL;
++
++ raw_spin_lock_init(&rq->lock);
++ rq->nr_running = rq->nr_uninterruptible = 0;
++ rq->calc_load_active = 0;
++ rq->calc_load_update = jiffies + LOAD_FREQ;
++#ifdef CONFIG_SMP
++ rq->online = false;
++ rq->cpu = i;
++
++#ifdef CONFIG_SCHED_SMT
++ rq->active_balance = 0;
++#endif
++
++#ifdef CONFIG_NO_HZ_COMMON
++ INIT_CSD(&rq->nohz_csd, nohz_csd_func, rq);
++#endif
++ rq->balance_callback = &balance_push_callback;
++#ifdef CONFIG_HOTPLUG_CPU
++ rcuwait_init(&rq->hotplug_wait);
++#endif
++#endif /* CONFIG_SMP */
++ rq->nr_switches = 0;
++
++ hrtick_rq_init(rq);
++ atomic_set(&rq->nr_iowait, 0);
++
++ zalloc_cpumask_var_node(&rq->scratch_mask, GFP_KERNEL, cpu_to_node(i));
++ }
++#ifdef CONFIG_SMP
++ /* Set rq->online for cpu 0 */
++ cpu_rq(0)->online = true;
++#endif
++ /*
++ * The boot idle thread does lazy MMU switching as well:
++ */
++ mmgrab(&init_mm);
++ enter_lazy_tlb(&init_mm, current);
++
++ /*
++ * The idle task doesn't need the kthread struct to function, but it
++ * is dressed up as a per-CPU kthread and thus needs to play the part
++ * if we want to avoid special-casing it in code that deals with per-CPU
++ * kthreads.
++ */
++ WARN_ON(!set_kthread_struct(current));
++
++ /*
++ * Make us the idle thread. Technically, schedule() should not be
++ * called from this thread, however somewhere below it might be,
++ * but because we are the idle thread, we just pick up running again
++ * when this runqueue becomes "idle".
++ */
++ init_idle(current, smp_processor_id());
++
++ calc_load_update = jiffies + LOAD_FREQ;
++
++#ifdef CONFIG_SMP
++ idle_thread_set_boot_cpu();
++ balance_push_set(smp_processor_id(), false);
++
++ sched_init_topology_cpumask_early();
++#endif /* SMP */
++
++ preempt_dynamic_init();
++}
++
++#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
++
++void __might_sleep(const char *file, int line)
++{
++ unsigned int state = get_current_state();
++ /*
++ * Blocking primitives will set (and therefore destroy) current->state,
++ * since we will exit with TASK_RUNNING make sure we enter with it,
++ * otherwise we will destroy state.
++ */
++ WARN_ONCE(state != TASK_RUNNING && current->task_state_change,
++ "do not call blocking ops when !TASK_RUNNING; "
++ "state=%x set at [<%p>] %pS\n", state,
++ (void *)current->task_state_change,
++ (void *)current->task_state_change);
++
++ __might_resched(file, line, 0);
++}
++EXPORT_SYMBOL(__might_sleep);
++
++static void print_preempt_disable_ip(int preempt_offset, unsigned long ip)
++{
++ if (!IS_ENABLED(CONFIG_DEBUG_PREEMPT))
++ return;
++
++ if (preempt_count() == preempt_offset)
++ return;
++
++ pr_err("Preemption disabled at:");
++ print_ip_sym(KERN_ERR, ip);
++}
++
++static inline bool resched_offsets_ok(unsigned int offsets)
++{
++ unsigned int nested = preempt_count();
++
++ nested += rcu_preempt_depth() << MIGHT_RESCHED_RCU_SHIFT;
++
++ return nested == offsets;
++}
++
++void __might_resched(const char *file, int line, unsigned int offsets)
++{
++ /* Ratelimiting timestamp: */
++ static unsigned long prev_jiffy;
++
++ unsigned long preempt_disable_ip;
++
++ /* WARN_ON_ONCE() by default, no rate limit required: */
++ rcu_sleep_check();
++
++ if ((resched_offsets_ok(offsets) && !irqs_disabled() &&
++ !is_idle_task(current) && !current->non_block_count) ||
++ system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
++ oops_in_progress)
++ return;
++ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++ return;
++ prev_jiffy = jiffies;
++
++ /* Save this before calling printk(), since that will clobber it: */
++ preempt_disable_ip = get_preempt_disable_ip(current);
++
++ pr_err("BUG: sleeping function called from invalid context at %s:%d\n",
++ file, line);
++ pr_err("in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
++ in_atomic(), irqs_disabled(), current->non_block_count,
++ current->pid, current->comm);
++ pr_err("preempt_count: %x, expected: %x\n", preempt_count(),
++ offsets & MIGHT_RESCHED_PREEMPT_MASK);
++
++ if (IS_ENABLED(CONFIG_PREEMPT_RCU)) {
++ pr_err("RCU nest depth: %d, expected: %u\n",
++ rcu_preempt_depth(), offsets >> MIGHT_RESCHED_RCU_SHIFT);
++ }
++
++ if (task_stack_end_corrupted(current))
++ pr_emerg("Thread overran stack, or stack corrupted\n");
++
++ debug_show_held_locks(current);
++ if (irqs_disabled())
++ print_irqtrace_events(current);
++
++ print_preempt_disable_ip(offsets & MIGHT_RESCHED_PREEMPT_MASK,
++ preempt_disable_ip);
++
++ dump_stack();
++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL(__might_resched);
++
++void __cant_sleep(const char *file, int line, int preempt_offset)
++{
++ static unsigned long prev_jiffy;
++
++ if (irqs_disabled())
++ return;
++
++ if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
++ return;
++
++ if (preempt_count() > preempt_offset)
++ return;
++
++ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++ return;
++ prev_jiffy = jiffies;
++
++ printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
++ printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
++ in_atomic(), irqs_disabled(),
++ current->pid, current->comm);
++
++ debug_show_held_locks(current);
++ dump_stack();
++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL_GPL(__cant_sleep);
++
++#ifdef CONFIG_SMP
++void __cant_migrate(const char *file, int line)
++{
++ static unsigned long prev_jiffy;
++
++ if (irqs_disabled())
++ return;
++
++ if (is_migration_disabled(current))
++ return;
++
++ if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
++ return;
++
++ if (preempt_count() > 0)
++ return;
++
++ if (current->migration_flags & MDF_FORCE_ENABLED)
++ return;
++
++ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++ return;
++ prev_jiffy = jiffies;
++
++ pr_err("BUG: assuming non migratable context at %s:%d\n", file, line);
++ pr_err("in_atomic(): %d, irqs_disabled(): %d, migration_disabled() %u pid: %d, name: %s\n",
++ in_atomic(), irqs_disabled(), is_migration_disabled(current),
++ current->pid, current->comm);
++
++ debug_show_held_locks(current);
++ dump_stack();
++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL_GPL(__cant_migrate);
++#endif
++#endif
++
++#ifdef CONFIG_MAGIC_SYSRQ
++void normalize_rt_tasks(void)
++{
++ struct task_struct *g, *p;
++ struct sched_attr attr = {
++ .sched_policy = SCHED_NORMAL,
++ };
++
++ read_lock(&tasklist_lock);
++ for_each_process_thread(g, p) {
++ /*
++ * Only normalize user tasks:
++ */
++ if (p->flags & PF_KTHREAD)
++ continue;
++
++ schedstat_set(p->stats.wait_start, 0);
++ schedstat_set(p->stats.sleep_start, 0);
++ schedstat_set(p->stats.block_start, 0);
++
++ if (!rt_task(p)) {
++ /*
++ * Renice negative nice level userspace
++ * tasks back to 0:
++ */
++ if (task_nice(p) < 0)
++ set_user_nice(p, 0);
++ continue;
++ }
++
++ __sched_setscheduler(p, &attr, false, false);
++ }
++ read_unlock(&tasklist_lock);
++}
++#endif /* CONFIG_MAGIC_SYSRQ */
++
++#if defined(CONFIG_KGDB_KDB)
++/*
++ * These functions are only useful for kdb.
++ *
++ * They can only be called when the whole system has been
++ * stopped - every CPU needs to be quiescent, and no scheduling
++ * activity can take place. Using them for anything else would
++ * be a serious bug, and as a result, they aren't even visible
++ * under any other configuration.
++ */
++
++/**
++ * curr_task - return the current task for a given CPU.
++ * @cpu: the processor in question.
++ *
++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
++ *
++ * Return: The current task for @cpu.
++ */
++struct task_struct *curr_task(int cpu)
++{
++ return cpu_curr(cpu);
++}
++
++#endif /* defined(CONFIG_KGDB_KDB) */
++
++#ifdef CONFIG_CGROUP_SCHED
++static void sched_free_group(struct task_group *tg)
++{
++ kmem_cache_free(task_group_cache, tg);
++}
++
++static void sched_free_group_rcu(struct rcu_head *rhp)
++{
++ sched_free_group(container_of(rhp, struct task_group, rcu));
++}
++
++static void sched_unregister_group(struct task_group *tg)
++{
++ /*
++ * We have to wait for yet another RCU grace period to expire, as
++ * print_cfs_stats() might run concurrently.
++ */
++ call_rcu(&tg->rcu, sched_free_group_rcu);
++}
++
++/* allocate runqueue etc for a new task group */
++struct task_group *sched_create_group(struct task_group *parent)
++{
++ struct task_group *tg;
++
++ tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
++ if (!tg)
++ return ERR_PTR(-ENOMEM);
++
++ return tg;
++}
++
++void sched_online_group(struct task_group *tg, struct task_group *parent)
++{
++}
++
++/* rcu callback to free various structures associated with a task group */
++static void sched_unregister_group_rcu(struct rcu_head *rhp)
++{
++ /* Now it should be safe to free those cfs_rqs: */
++ sched_unregister_group(container_of(rhp, struct task_group, rcu));
++}
++
++void sched_destroy_group(struct task_group *tg)
++{
++ /* Wait for possible concurrent references to cfs_rqs complete: */
++ call_rcu(&tg->rcu, sched_unregister_group_rcu);
++}
++
++void sched_release_group(struct task_group *tg)
++{
++}
++
++static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
++{
++ return css ? container_of(css, struct task_group, css) : NULL;
++}
++
++static struct cgroup_subsys_state *
++cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
++{
++ struct task_group *parent = css_tg(parent_css);
++ struct task_group *tg;
++
++ if (!parent) {
++ /* This is early initialization for the top cgroup */
++ return &root_task_group.css;
++ }
++
++ tg = sched_create_group(parent);
++ if (IS_ERR(tg))
++ return ERR_PTR(-ENOMEM);
++ return &tg->css;
++}
++
++/* Expose task group only after completing cgroup initialization */
++static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
++{
++ struct task_group *tg = css_tg(css);
++ struct task_group *parent = css_tg(css->parent);
++
++ if (parent)
++ sched_online_group(tg, parent);
++ return 0;
++}
++
++static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
++{
++ struct task_group *tg = css_tg(css);
++
++ sched_release_group(tg);
++}
++
++static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
++{
++ struct task_group *tg = css_tg(css);
++
++ /*
++ * Relies on the RCU grace period between css_released() and this.
++ */
++ sched_unregister_group(tg);
++}
++
++#ifdef CONFIG_RT_GROUP_SCHED
++static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
++{
++ return 0;
++}
++#endif
++
++static void cpu_cgroup_attach(struct cgroup_taskset *tset)
++{
++}
++
++#ifdef CONFIG_FAIR_GROUP_SCHED
++static DEFINE_MUTEX(shares_mutex);
++
++int sched_group_set_shares(struct task_group *tg, unsigned long shares)
++{
++ /*
++ * We can't change the weight of the root cgroup.
++ */
++ if (&root_task_group == tg)
++ return -EINVAL;
++
++ shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
++
++ mutex_lock(&shares_mutex);
++ if (tg->shares == shares)
++ goto done;
++
++ tg->shares = shares;
++done:
++ mutex_unlock(&shares_mutex);
++ return 0;
++}
++
++static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
++ struct cftype *cftype, u64 shareval)
++{
++ if (shareval > scale_load_down(ULONG_MAX))
++ shareval = MAX_SHARES;
++ return sched_group_set_shares(css_tg(css), scale_load(shareval));
++}
++
++static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ struct task_group *tg = css_tg(css);
++
++ return (u64) scale_load_down(tg->shares);
++}
++#endif
++
++static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
++ struct cftype *cftype, s64 cfs_quota_us)
++{
++ return 0;
++}
++
++static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
++ struct cftype *cftype, u64 cfs_period_us)
++{
++ return 0;
++}
++
++static u64 cpu_cfs_burst_read_u64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_cfs_burst_write_u64(struct cgroup_subsys_state *css,
++ struct cftype *cftype, u64 cfs_burst_us)
++{
++ return 0;
++}
++
++static int cpu_cfs_stat_show(struct seq_file *sf, void *v)
++{
++ return 0;
++}
++
++static int cpu_cfs_local_stat_show(struct seq_file *sf, void *v)
++{
++ return 0;
++}
++
++static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
++ struct cftype *cft, s64 val)
++{
++ return 0;
++}
++
++static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
++ struct cftype *cftype, u64 rt_period_us)
++{
++ return 0;
++}
++
++static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_uclamp_min_show(struct seq_file *sf, void *v)
++{
++ return 0;
++}
++
++static int cpu_uclamp_max_show(struct seq_file *sf, void *v)
++{
++ return 0;
++}
++
++static ssize_t cpu_uclamp_min_write(struct kernfs_open_file *of,
++ char *buf, size_t nbytes,
++ loff_t off)
++{
++ return nbytes;
++}
++
++static ssize_t cpu_uclamp_max_write(struct kernfs_open_file *of,
++ char *buf, size_t nbytes,
++ loff_t off)
++{
++ return nbytes;
++}
++
++static struct cftype cpu_legacy_files[] = {
++#ifdef CONFIG_FAIR_GROUP_SCHED
++ {
++ .name = "shares",
++ .read_u64 = cpu_shares_read_u64,
++ .write_u64 = cpu_shares_write_u64,
++ },
++#endif
++ {
++ .name = "cfs_quota_us",
++ .read_s64 = cpu_cfs_quota_read_s64,
++ .write_s64 = cpu_cfs_quota_write_s64,
++ },
++ {
++ .name = "cfs_period_us",
++ .read_u64 = cpu_cfs_period_read_u64,
++ .write_u64 = cpu_cfs_period_write_u64,
++ },
++ {
++ .name = "cfs_burst_us",
++ .read_u64 = cpu_cfs_burst_read_u64,
++ .write_u64 = cpu_cfs_burst_write_u64,
++ },
++ {
++ .name = "stat",
++ .seq_show = cpu_cfs_stat_show,
++ },
++ {
++ .name = "stat.local",
++ .seq_show = cpu_cfs_local_stat_show,
++ },
++ {
++ .name = "rt_runtime_us",
++ .read_s64 = cpu_rt_runtime_read,
++ .write_s64 = cpu_rt_runtime_write,
++ },
++ {
++ .name = "rt_period_us",
++ .read_u64 = cpu_rt_period_read_uint,
++ .write_u64 = cpu_rt_period_write_uint,
++ },
++ {
++ .name = "uclamp.min",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .seq_show = cpu_uclamp_min_show,
++ .write = cpu_uclamp_min_write,
++ },
++ {
++ .name = "uclamp.max",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .seq_show = cpu_uclamp_max_show,
++ .write = cpu_uclamp_max_write,
++ },
++ { } /* Terminate */
++};
++
++static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
++ struct cftype *cft, u64 weight)
++{
++ return 0;
++}
++
++static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
++ struct cftype *cft, s64 nice)
++{
++ return 0;
++}
++
++static s64 cpu_idle_read_s64(struct cgroup_subsys_state *css,
++ struct cftype *cft)
++{
++ return 0;
++}
++
++static int cpu_idle_write_s64(struct cgroup_subsys_state *css,
++ struct cftype *cft, s64 idle)
++{
++ return 0;
++}
++
++static int cpu_max_show(struct seq_file *sf, void *v)
++{
++ return 0;
++}
++
++static ssize_t cpu_max_write(struct kernfs_open_file *of,
++ char *buf, size_t nbytes, loff_t off)
++{
++ return nbytes;
++}
++
++static struct cftype cpu_files[] = {
++ {
++ .name = "weight",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .read_u64 = cpu_weight_read_u64,
++ .write_u64 = cpu_weight_write_u64,
++ },
++ {
++ .name = "weight.nice",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .read_s64 = cpu_weight_nice_read_s64,
++ .write_s64 = cpu_weight_nice_write_s64,
++ },
++ {
++ .name = "idle",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .read_s64 = cpu_idle_read_s64,
++ .write_s64 = cpu_idle_write_s64,
++ },
++ {
++ .name = "max",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .seq_show = cpu_max_show,
++ .write = cpu_max_write,
++ },
++ {
++ .name = "max.burst",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .read_u64 = cpu_cfs_burst_read_u64,
++ .write_u64 = cpu_cfs_burst_write_u64,
++ },
++ {
++ .name = "uclamp.min",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .seq_show = cpu_uclamp_min_show,
++ .write = cpu_uclamp_min_write,
++ },
++ {
++ .name = "uclamp.max",
++ .flags = CFTYPE_NOT_ON_ROOT,
++ .seq_show = cpu_uclamp_max_show,
++ .write = cpu_uclamp_max_write,
++ },
++ { } /* terminate */
++};
++
++static int cpu_extra_stat_show(struct seq_file *sf,
++ struct cgroup_subsys_state *css)
++{
++ return 0;
++}
++
++static int cpu_local_stat_show(struct seq_file *sf,
++ struct cgroup_subsys_state *css)
++{
++ return 0;
++}
++
++struct cgroup_subsys cpu_cgrp_subsys = {
++ .css_alloc = cpu_cgroup_css_alloc,
++ .css_online = cpu_cgroup_css_online,
++ .css_released = cpu_cgroup_css_released,
++ .css_free = cpu_cgroup_css_free,
++ .css_extra_stat_show = cpu_extra_stat_show,
++ .css_local_stat_show = cpu_local_stat_show,
++#ifdef CONFIG_RT_GROUP_SCHED
++ .can_attach = cpu_cgroup_can_attach,
++#endif
++ .attach = cpu_cgroup_attach,
++ .legacy_cftypes = cpu_legacy_files,
++ .dfl_cftypes = cpu_files,
++ .early_init = true,
++ .threaded = true,
++};
++#endif /* CONFIG_CGROUP_SCHED */
++
++#undef CREATE_TRACE_POINTS
++
++#ifdef CONFIG_SCHED_MM_CID
++
++#
++/*
++ * @cid_lock: Guarantee forward-progress of cid allocation.
++ *
++ * Concurrency ID allocation within a bitmap is mostly lock-free. The cid_lock
++ * is only used when contention is detected by the lock-free allocation so
++ * forward progress can be guaranteed.
++ */
++DEFINE_RAW_SPINLOCK(cid_lock);
++
++/*
++ * @use_cid_lock: Select cid allocation behavior: lock-free vs spinlock.
++ *
++ * When @use_cid_lock is 0, the cid allocation is lock-free. When contention is
++ * detected, it is set to 1 to ensure that all newly coming allocations are
++ * serialized by @cid_lock until the allocation which detected contention
++ * completes and sets @use_cid_lock back to 0. This guarantees forward progress
++ * of a cid allocation.
++ */
++int use_cid_lock;
++
++/*
++ * mm_cid remote-clear implements a lock-free algorithm to clear per-mm/cpu cid
++ * concurrently with respect to the execution of the source runqueue context
++ * switch.
++ *
++ * There is one basic properties we want to guarantee here:
++ *
++ * (1) Remote-clear should _never_ mark a per-cpu cid UNSET when it is actively
++ * used by a task. That would lead to concurrent allocation of the cid and
++ * userspace corruption.
++ *
++ * Provide this guarantee by introducing a Dekker memory ordering to guarantee
++ * that a pair of loads observe at least one of a pair of stores, which can be
++ * shown as:
++ *
++ * X = Y = 0
++ *
++ * w[X]=1 w[Y]=1
++ * MB MB
++ * r[Y]=y r[X]=x
++ *
++ * Which guarantees that x==0 && y==0 is impossible. But rather than using
++ * values 0 and 1, this algorithm cares about specific state transitions of the
++ * runqueue current task (as updated by the scheduler context switch), and the
++ * per-mm/cpu cid value.
++ *
++ * Let's introduce task (Y) which has task->mm == mm and task (N) which has
++ * task->mm != mm for the rest of the discussion. There are two scheduler state
++ * transitions on context switch we care about:
++ *
++ * (TSA) Store to rq->curr with transition from (N) to (Y)
++ *
++ * (TSB) Store to rq->curr with transition from (Y) to (N)
++ *
++ * On the remote-clear side, there is one transition we care about:
++ *
++ * (TMA) cmpxchg to *pcpu_cid to set the LAZY flag
++ *
++ * There is also a transition to UNSET state which can be performed from all
++ * sides (scheduler, remote-clear). It is always performed with a cmpxchg which
++ * guarantees that only a single thread will succeed:
++ *
++ * (TMB) cmpxchg to *pcpu_cid to mark UNSET
++ *
++ * Just to be clear, what we do _not_ want to happen is a transition to UNSET
++ * when a thread is actively using the cid (property (1)).
++ *
++ * Let's looks at the relevant combinations of TSA/TSB, and TMA transitions.
++ *
++ * Scenario A) (TSA)+(TMA) (from next task perspective)
++ *
++ * CPU0 CPU1
++ *
++ * Context switch CS-1 Remote-clear
++ * - store to rq->curr: (N)->(Y) (TSA) - cmpxchg to *pcpu_id to LAZY (TMA)
++ * (implied barrier after cmpxchg)
++ * - switch_mm_cid()
++ * - memory barrier (see switch_mm_cid()
++ * comment explaining how this barrier
++ * is combined with other scheduler
++ * barriers)
++ * - mm_cid_get (next)
++ * - READ_ONCE(*pcpu_cid) - rcu_dereference(src_rq->curr)
++ *
++ * This Dekker ensures that either task (Y) is observed by the
++ * rcu_dereference() or the LAZY flag is observed by READ_ONCE(), or both are
++ * observed.
++ *
++ * If task (Y) store is observed by rcu_dereference(), it means that there is
++ * still an active task on the cpu. Remote-clear will therefore not transition
++ * to UNSET, which fulfills property (1).
++ *
++ * If task (Y) is not observed, but the lazy flag is observed by READ_ONCE(),
++ * it will move its state to UNSET, which clears the percpu cid perhaps
++ * uselessly (which is not an issue for correctness). Because task (Y) is not
++ * observed, CPU1 can move ahead to set the state to UNSET. Because moving
++ * state to UNSET is done with a cmpxchg expecting that the old state has the
++ * LAZY flag set, only one thread will successfully UNSET.
++ *
++ * If both states (LAZY flag and task (Y)) are observed, the thread on CPU0
++ * will observe the LAZY flag and transition to UNSET (perhaps uselessly), and
++ * CPU1 will observe task (Y) and do nothing more, which is fine.
++ *
++ * What we are effectively preventing with this Dekker is a scenario where
++ * neither LAZY flag nor store (Y) are observed, which would fail property (1)
++ * because this would UNSET a cid which is actively used.
++ */
++
++void sched_mm_cid_migrate_from(struct task_struct *t)
++{
++ t->migrate_from_cpu = task_cpu(t);
++}
++
++static
++int __sched_mm_cid_migrate_from_fetch_cid(struct rq *src_rq,
++ struct task_struct *t,
++ struct mm_cid *src_pcpu_cid)
++{
++ struct mm_struct *mm = t->mm;
++ struct task_struct *src_task;
++ int src_cid, last_mm_cid;
++
++ if (!mm)
++ return -1;
++
++ last_mm_cid = t->last_mm_cid;
++ /*
++ * If the migrated task has no last cid, or if the current
++ * task on src rq uses the cid, it means the source cid does not need
++ * to be moved to the destination cpu.
++ */
++ if (last_mm_cid == -1)
++ return -1;
++ src_cid = READ_ONCE(src_pcpu_cid->cid);
++ if (!mm_cid_is_valid(src_cid) || last_mm_cid != src_cid)
++ return -1;
++
++ /*
++ * If we observe an active task using the mm on this rq, it means we
++ * are not the last task to be migrated from this cpu for this mm, so
++ * there is no need to move src_cid to the destination cpu.
++ */
++ rcu_read_lock();
++ src_task = rcu_dereference(src_rq->curr);
++ if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) {
++ rcu_read_unlock();
++ t->last_mm_cid = -1;
++ return -1;
++ }
++ rcu_read_unlock();
++
++ return src_cid;
++}
++
++static
++int __sched_mm_cid_migrate_from_try_steal_cid(struct rq *src_rq,
++ struct task_struct *t,
++ struct mm_cid *src_pcpu_cid,
++ int src_cid)
++{
++ struct task_struct *src_task;
++ struct mm_struct *mm = t->mm;
++ int lazy_cid;
++
++ if (src_cid == -1)
++ return -1;
++
++ /*
++ * Attempt to clear the source cpu cid to move it to the destination
++ * cpu.
++ */
++ lazy_cid = mm_cid_set_lazy_put(src_cid);
++ if (!try_cmpxchg(&src_pcpu_cid->cid, &src_cid, lazy_cid))
++ return -1;
++
++ /*
++ * The implicit barrier after cmpxchg per-mm/cpu cid before loading
++ * rq->curr->mm matches the scheduler barrier in context_switch()
++ * between store to rq->curr and load of prev and next task's
++ * per-mm/cpu cid.
++ *
++ * The implicit barrier after cmpxchg per-mm/cpu cid before loading
++ * rq->curr->mm_cid_active matches the barrier in
++ * sched_mm_cid_exit_signals(), sched_mm_cid_before_execve(), and
++ * sched_mm_cid_after_execve() between store to t->mm_cid_active and
++ * load of per-mm/cpu cid.
++ */
++
++ /*
++ * If we observe an active task using the mm on this rq after setting
++ * the lazy-put flag, this task will be responsible for transitioning
++ * from lazy-put flag set to MM_CID_UNSET.
++ */
++ scoped_guard (rcu) {
++ src_task = rcu_dereference(src_rq->curr);
++ if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) {
++ rcu_read_unlock();
++ /*
++ * We observed an active task for this mm, there is therefore
++ * no point in moving this cid to the destination cpu.
++ */
++ t->last_mm_cid = -1;
++ return -1;
++ }
++ }
++
++ /*
++ * The src_cid is unused, so it can be unset.
++ */
++ if (!try_cmpxchg(&src_pcpu_cid->cid, &lazy_cid, MM_CID_UNSET))
++ return -1;
++ return src_cid;
++}
++
++/*
++ * Migration to dst cpu. Called with dst_rq lock held.
++ * Interrupts are disabled, which keeps the window of cid ownership without the
++ * source rq lock held small.
++ */
++void sched_mm_cid_migrate_to(struct rq *dst_rq, struct task_struct *t, int src_cpu)
++{
++ struct mm_cid *src_pcpu_cid, *dst_pcpu_cid;
++ struct mm_struct *mm = t->mm;
++ int src_cid, dst_cid;
++ struct rq *src_rq;
++
++ lockdep_assert_rq_held(dst_rq);
++
++ if (!mm)
++ return;
++ if (src_cpu == -1) {
++ t->last_mm_cid = -1;
++ return;
++ }
++ /*
++ * Move the src cid if the dst cid is unset. This keeps id
++ * allocation closest to 0 in cases where few threads migrate around
++ * many cpus.
++ *
++ * If destination cid is already set, we may have to just clear
++ * the src cid to ensure compactness in frequent migrations
++ * scenarios.
++ *
++ * It is not useful to clear the src cid when the number of threads is
++ * greater or equal to the number of allowed cpus, because user-space
++ * can expect that the number of allowed cids can reach the number of
++ * allowed cpus.
++ */
++ dst_pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu_of(dst_rq));
++ dst_cid = READ_ONCE(dst_pcpu_cid->cid);
++ if (!mm_cid_is_unset(dst_cid) &&
++ atomic_read(&mm->mm_users) >= t->nr_cpus_allowed)
++ return;
++ src_pcpu_cid = per_cpu_ptr(mm->pcpu_cid, src_cpu);
++ src_rq = cpu_rq(src_cpu);
++ src_cid = __sched_mm_cid_migrate_from_fetch_cid(src_rq, t, src_pcpu_cid);
++ if (src_cid == -1)
++ return;
++ src_cid = __sched_mm_cid_migrate_from_try_steal_cid(src_rq, t, src_pcpu_cid,
++ src_cid);
++ if (src_cid == -1)
++ return;
++ if (!mm_cid_is_unset(dst_cid)) {
++ __mm_cid_put(mm, src_cid);
++ return;
++ }
++ /* Move src_cid to dst cpu. */
++ mm_cid_snapshot_time(dst_rq, mm);
++ WRITE_ONCE(dst_pcpu_cid->cid, src_cid);
++}
++
++static void sched_mm_cid_remote_clear(struct mm_struct *mm, struct mm_cid *pcpu_cid,
++ int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++ struct task_struct *t;
++ int cid, lazy_cid;
++
++ cid = READ_ONCE(pcpu_cid->cid);
++ if (!mm_cid_is_valid(cid))
++ return;
++
++ /*
++ * Clear the cpu cid if it is set to keep cid allocation compact. If
++ * there happens to be other tasks left on the source cpu using this
++ * mm, the next task using this mm will reallocate its cid on context
++ * switch.
++ */
++ lazy_cid = mm_cid_set_lazy_put(cid);
++ if (!try_cmpxchg(&pcpu_cid->cid, &cid, lazy_cid))
++ return;
++
++ /*
++ * The implicit barrier after cmpxchg per-mm/cpu cid before loading
++ * rq->curr->mm matches the scheduler barrier in context_switch()
++ * between store to rq->curr and load of prev and next task's
++ * per-mm/cpu cid.
++ *
++ * The implicit barrier after cmpxchg per-mm/cpu cid before loading
++ * rq->curr->mm_cid_active matches the barrier in
++ * sched_mm_cid_exit_signals(), sched_mm_cid_before_execve(), and
++ * sched_mm_cid_after_execve() between store to t->mm_cid_active and
++ * load of per-mm/cpu cid.
++ */
++
++ /*
++ * If we observe an active task using the mm on this rq after setting
++ * the lazy-put flag, that task will be responsible for transitioning
++ * from lazy-put flag set to MM_CID_UNSET.
++ */
++ scoped_guard (rcu) {
++ t = rcu_dereference(rq->curr);
++ if (READ_ONCE(t->mm_cid_active) && t->mm == mm)
++ return;
++ }
++
++ /*
++ * The cid is unused, so it can be unset.
++ * Disable interrupts to keep the window of cid ownership without rq
++ * lock small.
++ */
++ scoped_guard (irqsave) {
++ if (try_cmpxchg(&pcpu_cid->cid, &lazy_cid, MM_CID_UNSET))
++ __mm_cid_put(mm, cid);
++ }
++}
++
++static void sched_mm_cid_remote_clear_old(struct mm_struct *mm, int cpu)
++{
++ struct rq *rq = cpu_rq(cpu);
++ struct mm_cid *pcpu_cid;
++ struct task_struct *curr;
++ u64 rq_clock;
++
++ /*
++ * rq->clock load is racy on 32-bit but one spurious clear once in a
++ * while is irrelevant.
++ */
++ rq_clock = READ_ONCE(rq->clock);
++ pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu);
++
++ /*
++ * In order to take care of infrequently scheduled tasks, bump the time
++ * snapshot associated with this cid if an active task using the mm is
++ * observed on this rq.
++ */
++ scoped_guard (rcu) {
++ curr = rcu_dereference(rq->curr);
++ if (READ_ONCE(curr->mm_cid_active) && curr->mm == mm) {
++ WRITE_ONCE(pcpu_cid->time, rq_clock);
++ return;
++ }
++ }
++
++ if (rq_clock < pcpu_cid->time + SCHED_MM_CID_PERIOD_NS)
++ return;
++ sched_mm_cid_remote_clear(mm, pcpu_cid, cpu);
++}
++
++static void sched_mm_cid_remote_clear_weight(struct mm_struct *mm, int cpu,
++ int weight)
++{
++ struct mm_cid *pcpu_cid;
++ int cid;
++
++ pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu);
++ cid = READ_ONCE(pcpu_cid->cid);
++ if (!mm_cid_is_valid(cid) || cid < weight)
++ return;
++ sched_mm_cid_remote_clear(mm, pcpu_cid, cpu);
++}
++
++static void task_mm_cid_work(struct callback_head *work)
++{
++ unsigned long now = jiffies, old_scan, next_scan;
++ struct task_struct *t = current;
++ struct cpumask *cidmask;
++ struct mm_struct *mm;
++ int weight, cpu;
++
++ SCHED_WARN_ON(t != container_of(work, struct task_struct, cid_work));
++
++ work->next = work; /* Prevent double-add */
++ if (t->flags & PF_EXITING)
++ return;
++ mm = t->mm;
++ if (!mm)
++ return;
++ old_scan = READ_ONCE(mm->mm_cid_next_scan);
++ next_scan = now + msecs_to_jiffies(MM_CID_SCAN_DELAY);
++ if (!old_scan) {
++ unsigned long res;
++
++ res = cmpxchg(&mm->mm_cid_next_scan, old_scan, next_scan);
++ if (res != old_scan)
++ old_scan = res;
++ else
++ old_scan = next_scan;
++ }
++ if (time_before(now, old_scan))
++ return;
++ if (!try_cmpxchg(&mm->mm_cid_next_scan, &old_scan, next_scan))
++ return;
++ cidmask = mm_cidmask(mm);
++ /* Clear cids that were not recently used. */
++ for_each_possible_cpu(cpu)
++ sched_mm_cid_remote_clear_old(mm, cpu);
++ weight = cpumask_weight(cidmask);
++ /*
++ * Clear cids that are greater or equal to the cidmask weight to
++ * recompact it.
++ */
++ for_each_possible_cpu(cpu)
++ sched_mm_cid_remote_clear_weight(mm, cpu, weight);
++}
++
++void init_sched_mm_cid(struct task_struct *t)
++{
++ struct mm_struct *mm = t->mm;
++ int mm_users = 0;
++
++ if (mm) {
++ mm_users = atomic_read(&mm->mm_users);
++ if (mm_users == 1)
++ mm->mm_cid_next_scan = jiffies + msecs_to_jiffies(MM_CID_SCAN_DELAY);
++ }
++ t->cid_work.next = &t->cid_work; /* Protect against double add */
++ init_task_work(&t->cid_work, task_mm_cid_work);
++}
++
++void task_tick_mm_cid(struct rq *rq, struct task_struct *curr)
++{
++ struct callback_head *work = &curr->cid_work;
++ unsigned long now = jiffies;
++
++ if (!curr->mm || (curr->flags & (PF_EXITING | PF_KTHREAD)) ||
++ work->next != work)
++ return;
++ if (time_before(now, READ_ONCE(curr->mm->mm_cid_next_scan)))
++ return;
++ task_work_add(curr, work, TWA_RESUME);
++}
++
++void sched_mm_cid_exit_signals(struct task_struct *t)
++{
++ struct mm_struct *mm = t->mm;
++ struct rq *rq;
++
++ if (!mm)
++ return;
++
++ preempt_disable();
++ rq = this_rq();
++ guard(rq_lock_irqsave)(rq);
++ preempt_enable_no_resched(); /* holding spinlock */
++ WRITE_ONCE(t->mm_cid_active, 0);
++ /*
++ * Store t->mm_cid_active before loading per-mm/cpu cid.
++ * Matches barrier in sched_mm_cid_remote_clear_old().
++ */
++ smp_mb();
++ mm_cid_put(mm);
++ t->last_mm_cid = t->mm_cid = -1;
++}
++
++void sched_mm_cid_before_execve(struct task_struct *t)
++{
++ struct mm_struct *mm = t->mm;
++ struct rq *rq;
++
++ if (!mm)
++ return;
++
++ preempt_disable();
++ rq = this_rq();
++ guard(rq_lock_irqsave)(rq);
++ preempt_enable_no_resched(); /* holding spinlock */
++ WRITE_ONCE(t->mm_cid_active, 0);
++ /*
++ * Store t->mm_cid_active before loading per-mm/cpu cid.
++ * Matches barrier in sched_mm_cid_remote_clear_old().
++ */
++ smp_mb();
++ mm_cid_put(mm);
++ t->last_mm_cid = t->mm_cid = -1;
++}
++
++void sched_mm_cid_after_execve(struct task_struct *t)
++{
++ struct mm_struct *mm = t->mm;
++ struct rq *rq;
++
++ if (!mm)
++ return;
++
++ preempt_disable();
++ rq = this_rq();
++ scoped_guard (rq_lock_irqsave, rq) {
++ preempt_enable_no_resched(); /* holding spinlock */
++ WRITE_ONCE(t->mm_cid_active, 1);
++ /*
++ * Store t->mm_cid_active before loading per-mm/cpu cid.
++ * Matches barrier in sched_mm_cid_remote_clear_old().
++ */
++ smp_mb();
++ t->last_mm_cid = t->mm_cid = mm_cid_get(rq, mm);
++ }
++ rseq_set_notify_resume(t);
++}
++
++void sched_mm_cid_fork(struct task_struct *t)
++{
++ WARN_ON_ONCE(!t->mm || t->mm_cid != -1);
++ t->mm_cid_active = 1;
++}
++#endif
+diff --git a/kernel/sched/alt_debug.c b/kernel/sched/alt_debug.c
+new file mode 100644
+index 000000000000..1212a031700e
+--- /dev/null
++++ b/kernel/sched/alt_debug.c
+@@ -0,0 +1,31 @@
++/*
++ * kernel/sched/alt_debug.c
++ *
++ * Print the alt scheduler debugging details
++ *
++ * Author: Alfred Chen
++ * Date : 2020
++ */
++#include "sched.h"
++
++/*
++ * This allows printing both to /proc/sched_debug and
++ * to the console
++ */
++#define SEQ_printf(m, x...) \
++ do { \
++ if (m) \
++ seq_printf(m, x); \
++ else \
++ pr_cont(x); \
++ } while (0)
++
++void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
++ struct seq_file *m)
++{
++ SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
++ get_nr_threads(p));
++}
++
++void proc_sched_set_task(struct task_struct *p)
++{}
+diff --git a/kernel/sched/alt_sched.h b/kernel/sched/alt_sched.h
+new file mode 100644
+index 000000000000..0eff5391092c
+--- /dev/null
++++ b/kernel/sched/alt_sched.h
+@@ -0,0 +1,923 @@
++#ifndef ALT_SCHED_H
++#define ALT_SCHED_H
++
++#include <linux/context_tracking.h>
++#include <linux/profile.h>
++#include <linux/stop_machine.h>
++#include <linux/syscalls.h>
++#include <linux/tick.h>
++
++#include <trace/events/power.h>
++#include <trace/events/sched.h>
++
++#include "../workqueue_internal.h"
++
++#include "cpupri.h"
++
++#define MIN_SCHED_NORMAL_PRIO (32)
++/*
++ * levels: RT(0-24), reserved(25-31), NORMAL(32-63), cpu idle task(64)
++ *
++ * -- BMQ --
++ * NORMAL: (lower boost range 12, NICE_WIDTH 40, higher boost range 12) / 2
++ * -- PDS --
++ * NORMAL: SCHED_EDGE_DELTA + ((NICE_WIDTH 40) / 2)
++ */
++#define SCHED_LEVELS (64 + 1)
++
++#define IDLE_TASK_SCHED_PRIO (SCHED_LEVELS - 1)
++
++#ifdef CONFIG_SCHED_DEBUG
++# define SCHED_WARN_ON(x) WARN_ONCE(x, #x)
++extern void resched_latency_warn(int cpu, u64 latency);
++#else
++# define SCHED_WARN_ON(x) ({ (void)(x), 0; })
++static inline void resched_latency_warn(int cpu, u64 latency) {}
++#endif
++
++/*
++ * Increase resolution of nice-level calculations for 64-bit architectures.
++ * The extra resolution improves shares distribution and load balancing of
++ * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
++ * hierarchies, especially on larger systems. This is not a user-visible change
++ * and does not change the user-interface for setting shares/weights.
++ *
++ * We increase resolution only if we have enough bits to allow this increased
++ * resolution (i.e. 64-bit). The costs for increasing resolution when 32-bit
++ * are pretty high and the returns do not justify the increased costs.
++ *
++ * Really only required when CONFIG_FAIR_GROUP_SCHED=y is also set, but to
++ * increase coverage and consistency always enable it on 64-bit platforms.
++ */
++#ifdef CONFIG_64BIT
++# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
++# define scale_load(w) ((w) << SCHED_FIXEDPOINT_SHIFT)
++# define scale_load_down(w) \
++({ \
++ unsigned long __w = (w); \
++ if (__w) \
++ __w = max(2UL, __w >> SCHED_FIXEDPOINT_SHIFT); \
++ __w; \
++})
++#else
++# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT)
++# define scale_load(w) (w)
++# define scale_load_down(w) (w)
++#endif
++
++#ifdef CONFIG_FAIR_GROUP_SCHED
++#define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
++
++/*
++ * A weight of 0 or 1 can cause arithmetics problems.
++ * A weight of a cfs_rq is the sum of weights of which entities
++ * are queued on this cfs_rq, so a weight of a entity should not be
++ * too large, so as the shares value of a task group.
++ * (The default weight is 1024 - so there's no practical
++ * limitation from this.)
++ */
++#define MIN_SHARES (1UL << 1)
++#define MAX_SHARES (1UL << 18)
++#endif
++
++/*
++ * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
++ */
++#ifdef CONFIG_SCHED_DEBUG
++# define const_debug __read_mostly
++#else
++# define const_debug const
++#endif
++
++/* task_struct::on_rq states: */
++#define TASK_ON_RQ_QUEUED 1
++#define TASK_ON_RQ_MIGRATING 2
++
++static inline int task_on_rq_queued(struct task_struct *p)
++{
++ return p->on_rq == TASK_ON_RQ_QUEUED;
++}
++
++static inline int task_on_rq_migrating(struct task_struct *p)
++{
++ return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
++}
++
++/* Wake flags. The first three directly map to some SD flag value */
++#define WF_EXEC 0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC */
++#define WF_FORK 0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK */
++#define WF_TTWU 0x08 /* Wakeup; maps to SD_BALANCE_WAKE */
++
++#define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */
++#define WF_MIGRATED 0x20 /* Internal use, task got migrated */
++#define WF_CURRENT_CPU 0x40 /* Prefer to move the wakee to the current CPU. */
++
++#ifdef CONFIG_SMP
++static_assert(WF_EXEC == SD_BALANCE_EXEC);
++static_assert(WF_FORK == SD_BALANCE_FORK);
++static_assert(WF_TTWU == SD_BALANCE_WAKE);
++#endif
++
++#define SCHED_QUEUE_BITS (SCHED_LEVELS - 1)
++
++struct sched_queue {
++ DECLARE_BITMAP(bitmap, SCHED_QUEUE_BITS);
++ struct list_head heads[SCHED_LEVELS];
++};
++
++struct rq;
++struct cpuidle_state;
++
++struct balance_callback {
++ struct balance_callback *next;
++ void (*func)(struct rq *rq);
++};
++
++/*
++ * This is the main, per-CPU runqueue data structure.
++ * This data should only be modified by the local cpu.
++ */
++struct rq {
++ /* runqueue lock: */
++ raw_spinlock_t lock;
++
++ struct task_struct __rcu *curr;
++ struct task_struct *idle;
++ struct task_struct *stop;
++ struct task_struct *skip;
++ struct mm_struct *prev_mm;
++
++ struct sched_queue queue;
++#ifdef CONFIG_SCHED_PDS
++ u64 time_edge;
++#endif
++ unsigned long prio;
++
++ /* switch count */
++ u64 nr_switches;
++
++ atomic_t nr_iowait;
++
++#ifdef CONFIG_SCHED_DEBUG
++ u64 last_seen_need_resched_ns;
++ int ticks_without_resched;
++#endif
++
++#ifdef CONFIG_MEMBARRIER
++ int membarrier_state;
++#endif
++
++#ifdef CONFIG_SMP
++ int cpu; /* cpu of this runqueue */
++ bool online;
++
++ unsigned int ttwu_pending;
++ unsigned char nohz_idle_balance;
++ unsigned char idle_balance;
++
++#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
++ struct sched_avg avg_irq;
++#endif
++
++#ifdef CONFIG_SCHED_SMT
++ int active_balance;
++ struct cpu_stop_work active_balance_work;
++#endif
++ struct balance_callback *balance_callback;
++#ifdef CONFIG_HOTPLUG_CPU
++ struct rcuwait hotplug_wait;
++#endif
++ unsigned int nr_pinned;
++
++#endif /* CONFIG_SMP */
++#ifdef CONFIG_IRQ_TIME_ACCOUNTING
++ u64 prev_irq_time;
++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
++#ifdef CONFIG_PARAVIRT
++ u64 prev_steal_time;
++#endif /* CONFIG_PARAVIRT */
++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
++ u64 prev_steal_time_rq;
++#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */
++
++ /* For genenal cpu load util */
++ s32 load_history;
++ u64 load_block;
++ u64 load_stamp;
++
++ /* calc_load related fields */
++ unsigned long calc_load_update;
++ long calc_load_active;
++
++ /* Ensure that all clocks are in the same cache line */
++ u64 clock ____cacheline_aligned;
++ u64 clock_task;
++#ifdef CONFIG_SCHED_BMQ
++ u64 last_ts_switch;
++#endif
++
++ unsigned int nr_running;
++ unsigned long nr_uninterruptible;
++
++#ifdef CONFIG_SCHED_HRTICK
++#ifdef CONFIG_SMP
++ call_single_data_t hrtick_csd;
++#endif
++ struct hrtimer hrtick_timer;
++ ktime_t hrtick_time;
++#endif
++
++#ifdef CONFIG_SCHEDSTATS
++
++ /* latency stats */
++ struct sched_info rq_sched_info;
++ unsigned long long rq_cpu_time;
++ /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
++
++ /* sys_sched_yield() stats */
++ unsigned int yld_count;
++
++ /* schedule() stats */
++ unsigned int sched_switch;
++ unsigned int sched_count;
++ unsigned int sched_goidle;
++
++ /* try_to_wake_up() stats */
++ unsigned int ttwu_count;
++ unsigned int ttwu_local;
++#endif /* CONFIG_SCHEDSTATS */
++
++#ifdef CONFIG_CPU_IDLE
++ /* Must be inspected within a rcu lock section */
++ struct cpuidle_state *idle_state;
++#endif
++
++#ifdef CONFIG_NO_HZ_COMMON
++#ifdef CONFIG_SMP
++ call_single_data_t nohz_csd;
++#endif
++ atomic_t nohz_flags;
++#endif /* CONFIG_NO_HZ_COMMON */
++
++ /* Scratch cpumask to be temporarily used under rq_lock */
++ cpumask_var_t scratch_mask;
++};
++
++extern unsigned int sysctl_sched_base_slice;
++
++extern unsigned long rq_load_util(struct rq *rq, unsigned long max);
++
++extern unsigned long calc_load_update;
++extern atomic_long_t calc_load_tasks;
++
++extern void calc_global_load_tick(struct rq *this_rq);
++extern long calc_load_fold_active(struct rq *this_rq, long adjust);
++
++DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
++#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
++#define this_rq() this_cpu_ptr(&runqueues)
++#define task_rq(p) cpu_rq(task_cpu(p))
++#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
++#define raw_rq() raw_cpu_ptr(&runqueues)
++
++#ifdef CONFIG_SMP
++#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
++void register_sched_domain_sysctl(void);
++void unregister_sched_domain_sysctl(void);
++#else
++static inline void register_sched_domain_sysctl(void)
++{
++}
++static inline void unregister_sched_domain_sysctl(void)
++{
++}
++#endif
++
++extern bool sched_smp_initialized;
++
++enum {
++ ITSELF_LEVEL_SPACE_HOLDER,
++#ifdef CONFIG_SCHED_SMT
++ SMT_LEVEL_SPACE_HOLDER,
++#endif
++ COREGROUP_LEVEL_SPACE_HOLDER,
++ CORE_LEVEL_SPACE_HOLDER,
++ OTHER_LEVEL_SPACE_HOLDER,
++ NR_CPU_AFFINITY_LEVELS
++};
++
++DECLARE_PER_CPU_ALIGNED(cpumask_t [NR_CPU_AFFINITY_LEVELS], sched_cpu_topo_masks);
++
++static inline int
++__best_mask_cpu(const cpumask_t *cpumask, const cpumask_t *mask)
++{
++ int cpu;
++
++ while ((cpu = cpumask_any_and(cpumask, mask)) >= nr_cpu_ids)
++ mask++;
++
++ return cpu;
++}
++
++static inline int best_mask_cpu(int cpu, const cpumask_t *mask)
++{
++ return __best_mask_cpu(mask, per_cpu(sched_cpu_topo_masks, cpu));
++}
++
++extern void flush_smp_call_function_queue(void);
++
++#else /* !CONFIG_SMP */
++static inline void flush_smp_call_function_queue(void) { }
++#endif
++
++#ifndef arch_scale_freq_tick
++static __always_inline
++void arch_scale_freq_tick(void)
++{
++}
++#endif
++
++#ifndef arch_scale_freq_capacity
++static __always_inline
++unsigned long arch_scale_freq_capacity(int cpu)
++{
++ return SCHED_CAPACITY_SCALE;
++}
++#endif
++
++static inline u64 __rq_clock_broken(struct rq *rq)
++{
++ return READ_ONCE(rq->clock);
++}
++
++static inline u64 rq_clock(struct rq *rq)
++{
++ /*
++ * Relax lockdep_assert_held() checking as in VRQ, call to
++ * sched_info_xxxx() may not held rq->lock
++ * lockdep_assert_held(&rq->lock);
++ */
++ return rq->clock;
++}
++
++static inline u64 rq_clock_task(struct rq *rq)
++{
++ /*
++ * Relax lockdep_assert_held() checking as in VRQ, call to
++ * sched_info_xxxx() may not held rq->lock
++ * lockdep_assert_held(&rq->lock);
++ */
++ return rq->clock_task;
++}
++
++/*
++ * {de,en}queue flags:
++ *
++ * DEQUEUE_SLEEP - task is no longer runnable
++ * ENQUEUE_WAKEUP - task just became runnable
++ *
++ */
++
++#define DEQUEUE_SLEEP 0x01
++
++#define ENQUEUE_WAKEUP 0x01
++
++
++/*
++ * Below are scheduler API which using in other kernel code
++ * It use the dummy rq_flags
++ * ToDo : BMQ need to support these APIs for compatibility with mainline
++ * scheduler code.
++ */
++struct rq_flags {
++ unsigned long flags;
++};
++
++struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++ __acquires(rq->lock);
++
++struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++ __acquires(p->pi_lock)
++ __acquires(rq->lock);
++
++static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
++ __releases(rq->lock)
++{
++ raw_spin_unlock(&rq->lock);
++}
++
++static inline void
++task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
++ __releases(rq->lock)
++ __releases(p->pi_lock)
++{
++ raw_spin_unlock(&rq->lock);
++ raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
++}
++
++static inline void
++rq_lock(struct rq *rq, struct rq_flags *rf)
++ __acquires(rq->lock)
++{
++ raw_spin_lock(&rq->lock);
++}
++
++static inline void
++rq_unlock(struct rq *rq, struct rq_flags *rf)
++ __releases(rq->lock)
++{
++ raw_spin_unlock(&rq->lock);
++}
++
++static inline void
++rq_lock_irq(struct rq *rq, struct rq_flags *rf)
++ __acquires(rq->lock)
++{
++ raw_spin_lock_irq(&rq->lock);
++}
++
++static inline void
++rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
++ __releases(rq->lock)
++{
++ raw_spin_unlock_irq(&rq->lock);
++}
++
++static inline struct rq *
++this_rq_lock_irq(struct rq_flags *rf)
++ __acquires(rq->lock)
++{
++ struct rq *rq;
++
++ local_irq_disable();
++ rq = this_rq();
++ raw_spin_lock(&rq->lock);
++
++ return rq;
++}
++
++static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
++{
++ return &rq->lock;
++}
++
++static inline raw_spinlock_t *rq_lockp(struct rq *rq)
++{
++ return __rq_lockp(rq);
++}
++
++static inline void lockdep_assert_rq_held(struct rq *rq)
++{
++ lockdep_assert_held(__rq_lockp(rq));
++}
++
++extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass);
++extern void raw_spin_rq_unlock(struct rq *rq);
++
++static inline void raw_spin_rq_lock(struct rq *rq)
++{
++ raw_spin_rq_lock_nested(rq, 0);
++}
++
++static inline void raw_spin_rq_lock_irq(struct rq *rq)
++{
++ local_irq_disable();
++ raw_spin_rq_lock(rq);
++}
++
++static inline void raw_spin_rq_unlock_irq(struct rq *rq)
++{
++ raw_spin_rq_unlock(rq);
++ local_irq_enable();
++}
++
++static inline int task_current(struct rq *rq, struct task_struct *p)
++{
++ return rq->curr == p;
++}
++
++static inline bool task_on_cpu(struct task_struct *p)
++{
++ return p->on_cpu;
++}
++
++extern int task_running_nice(struct task_struct *p);
++
++extern struct static_key_false sched_schedstats;
++
++#ifdef CONFIG_CPU_IDLE
++static inline void idle_set_state(struct rq *rq,
++ struct cpuidle_state *idle_state)
++{
++ rq->idle_state = idle_state;
++}
++
++static inline struct cpuidle_state *idle_get_state(struct rq *rq)
++{
++ WARN_ON(!rcu_read_lock_held());
++ return rq->idle_state;
++}
++#else
++static inline void idle_set_state(struct rq *rq,
++ struct cpuidle_state *idle_state)
++{
++}
++
++static inline struct cpuidle_state *idle_get_state(struct rq *rq)
++{
++ return NULL;
++}
++#endif
++
++static inline int cpu_of(const struct rq *rq)
++{
++#ifdef CONFIG_SMP
++ return rq->cpu;
++#else
++ return 0;
++#endif
++}
++
++#include "stats.h"
++
++#ifdef CONFIG_NO_HZ_COMMON
++#define NOHZ_BALANCE_KICK_BIT 0
++#define NOHZ_STATS_KICK_BIT 1
++
++#define NOHZ_BALANCE_KICK BIT(NOHZ_BALANCE_KICK_BIT)
++#define NOHZ_STATS_KICK BIT(NOHZ_STATS_KICK_BIT)
++
++#define NOHZ_KICK_MASK (NOHZ_BALANCE_KICK | NOHZ_STATS_KICK)
++
++#define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)
++
++/* TODO: needed?
++extern void nohz_balance_exit_idle(struct rq *rq);
++#else
++static inline void nohz_balance_exit_idle(struct rq *rq) { }
++*/
++#endif
++
++#ifdef CONFIG_IRQ_TIME_ACCOUNTING
++struct irqtime {
++ u64 total;
++ u64 tick_delta;
++ u64 irq_start_time;
++ struct u64_stats_sync sync;
++};
++
++DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
++
++/*
++ * Returns the irqtime minus the softirq time computed by ksoftirqd.
++ * Otherwise ksoftirqd's sum_exec_runtime is substracted its own runtime
++ * and never move forward.
++ */
++static inline u64 irq_time_read(int cpu)
++{
++ struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
++ unsigned int seq;
++ u64 total;
++
++ do {
++ seq = __u64_stats_fetch_begin(&irqtime->sync);
++ total = irqtime->total;
++ } while (__u64_stats_fetch_retry(&irqtime->sync, seq));
++
++ return total;
++}
++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
++
++#ifdef CONFIG_CPU_FREQ
++DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
++#endif /* CONFIG_CPU_FREQ */
++
++#ifdef CONFIG_NO_HZ_FULL
++extern int __init sched_tick_offload_init(void);
++#else
++static inline int sched_tick_offload_init(void) { return 0; }
++#endif
++
++#ifdef arch_scale_freq_capacity
++#ifndef arch_scale_freq_invariant
++#define arch_scale_freq_invariant() (true)
++#endif
++#else /* arch_scale_freq_capacity */
++#define arch_scale_freq_invariant() (false)
++#endif
++
++extern void schedule_idle(void);
++
++#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
++
++/*
++ * !! For sched_setattr_nocheck() (kernel) only !!
++ *
++ * This is actually gross. :(
++ *
++ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
++ * tasks, but still be able to sleep. We need this on platforms that cannot
++ * atomically change clock frequency. Remove once fast switching will be
++ * available on such platforms.
++ *
++ * SUGOV stands for SchedUtil GOVernor.
++ */
++#define SCHED_FLAG_SUGOV 0x10000000
++
++#ifdef CONFIG_MEMBARRIER
++/*
++ * The scheduler provides memory barriers required by membarrier between:
++ * - prior user-space memory accesses and store to rq->membarrier_state,
++ * - store to rq->membarrier_state and following user-space memory accesses.
++ * In the same way it provides those guarantees around store to rq->curr.
++ */
++static inline void membarrier_switch_mm(struct rq *rq,
++ struct mm_struct *prev_mm,
++ struct mm_struct *next_mm)
++{
++ int membarrier_state;
++
++ if (prev_mm == next_mm)
++ return;
++
++ membarrier_state = atomic_read(&next_mm->membarrier_state);
++ if (READ_ONCE(rq->membarrier_state) == membarrier_state)
++ return;
++
++ WRITE_ONCE(rq->membarrier_state, membarrier_state);
++}
++#else
++static inline void membarrier_switch_mm(struct rq *rq,
++ struct mm_struct *prev_mm,
++ struct mm_struct *next_mm)
++{
++}
++#endif
++
++#ifdef CONFIG_NUMA
++extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
++#else
++static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
++{
++ return nr_cpu_ids;
++}
++#endif
++
++extern void swake_up_all_locked(struct swait_queue_head *q);
++extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
++
++extern int try_to_wake_up(struct task_struct *tsk, unsigned int state, int wake_flags);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++extern int preempt_dynamic_mode;
++extern int sched_dynamic_mode(const char *str);
++extern void sched_dynamic_update(int mode);
++#endif
++
++static inline void nohz_run_idle_balance(int cpu) { }
++
++static inline
++unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
++ struct task_struct *p)
++{
++ return util;
++}
++
++static inline bool uclamp_rq_is_capped(struct rq *rq) { return false; }
++
++#ifdef CONFIG_SCHED_MM_CID
++
++#define SCHED_MM_CID_PERIOD_NS (100ULL * 1000000) /* 100ms */
++#define MM_CID_SCAN_DELAY 100 /* 100ms */
++
++extern raw_spinlock_t cid_lock;
++extern int use_cid_lock;
++
++extern void sched_mm_cid_migrate_from(struct task_struct *t);
++extern void sched_mm_cid_migrate_to(struct rq *dst_rq, struct task_struct *t, int src_cpu);
++extern void task_tick_mm_cid(struct rq *rq, struct task_struct *curr);
++extern void init_sched_mm_cid(struct task_struct *t);
++
++static inline void __mm_cid_put(struct mm_struct *mm, int cid)
++{
++ if (cid < 0)
++ return;
++ cpumask_clear_cpu(cid, mm_cidmask(mm));
++}
++
++/*
++ * The per-mm/cpu cid can have the MM_CID_LAZY_PUT flag set or transition to
++ * the MM_CID_UNSET state without holding the rq lock, but the rq lock needs to
++ * be held to transition to other states.
++ *
++ * State transitions synchronized with cmpxchg or try_cmpxchg need to be
++ * consistent across cpus, which prevents use of this_cpu_cmpxchg.
++ */
++static inline void mm_cid_put_lazy(struct task_struct *t)
++{
++ struct mm_struct *mm = t->mm;
++ struct mm_cid __percpu *pcpu_cid = mm->pcpu_cid;
++ int cid;
++
++ lockdep_assert_irqs_disabled();
++ cid = __this_cpu_read(pcpu_cid->cid);
++ if (!mm_cid_is_lazy_put(cid) ||
++ !try_cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, &cid, MM_CID_UNSET))
++ return;
++ __mm_cid_put(mm, mm_cid_clear_lazy_put(cid));
++}
++
++static inline int mm_cid_pcpu_unset(struct mm_struct *mm)
++{
++ struct mm_cid __percpu *pcpu_cid = mm->pcpu_cid;
++ int cid, res;
++
++ lockdep_assert_irqs_disabled();
++ cid = __this_cpu_read(pcpu_cid->cid);
++ for (;;) {
++ if (mm_cid_is_unset(cid))
++ return MM_CID_UNSET;
++ /*
++ * Attempt transition from valid or lazy-put to unset.
++ */
++ res = cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, cid, MM_CID_UNSET);
++ if (res == cid)
++ break;
++ cid = res;
++ }
++ return cid;
++}
++
++static inline void mm_cid_put(struct mm_struct *mm)
++{
++ int cid;
++
++ lockdep_assert_irqs_disabled();
++ cid = mm_cid_pcpu_unset(mm);
++ if (cid == MM_CID_UNSET)
++ return;
++ __mm_cid_put(mm, mm_cid_clear_lazy_put(cid));
++}
++
++static inline int __mm_cid_try_get(struct mm_struct *mm)
++{
++ struct cpumask *cpumask;
++ int cid;
++
++ cpumask = mm_cidmask(mm);
++ /*
++ * Retry finding first zero bit if the mask is temporarily
++ * filled. This only happens during concurrent remote-clear
++ * which owns a cid without holding a rq lock.
++ */
++ for (;;) {
++ cid = cpumask_first_zero(cpumask);
++ if (cid < nr_cpu_ids)
++ break;
++ cpu_relax();
++ }
++ if (cpumask_test_and_set_cpu(cid, cpumask))
++ return -1;
++ return cid;
++}
++
++/*
++ * Save a snapshot of the current runqueue time of this cpu
++ * with the per-cpu cid value, allowing to estimate how recently it was used.
++ */
++static inline void mm_cid_snapshot_time(struct rq *rq, struct mm_struct *mm)
++{
++ struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, cpu_of(rq));
++
++ lockdep_assert_rq_held(rq);
++ WRITE_ONCE(pcpu_cid->time, rq->clock);
++}
++
++static inline int __mm_cid_get(struct rq *rq, struct mm_struct *mm)
++{
++ int cid;
++
++ /*
++ * All allocations (even those using the cid_lock) are lock-free. If
++ * use_cid_lock is set, hold the cid_lock to perform cid allocation to
++ * guarantee forward progress.
++ */
++ if (!READ_ONCE(use_cid_lock)) {
++ cid = __mm_cid_try_get(mm);
++ if (cid >= 0)
++ goto end;
++ raw_spin_lock(&cid_lock);
++ } else {
++ raw_spin_lock(&cid_lock);
++ cid = __mm_cid_try_get(mm);
++ if (cid >= 0)
++ goto unlock;
++ }
++
++ /*
++ * cid concurrently allocated. Retry while forcing following
++ * allocations to use the cid_lock to ensure forward progress.
++ */
++ WRITE_ONCE(use_cid_lock, 1);
++ /*
++ * Set use_cid_lock before allocation. Only care about program order
++ * because this is only required for forward progress.
++ */
++ barrier();
++ /*
++ * Retry until it succeeds. It is guaranteed to eventually succeed once
++ * all newcoming allocations observe the use_cid_lock flag set.
++ */
++ do {
++ cid = __mm_cid_try_get(mm);
++ cpu_relax();
++ } while (cid < 0);
++ /*
++ * Allocate before clearing use_cid_lock. Only care about
++ * program order because this is for forward progress.
++ */
++ barrier();
++ WRITE_ONCE(use_cid_lock, 0);
++unlock:
++ raw_spin_unlock(&cid_lock);
++end:
++ mm_cid_snapshot_time(rq, mm);
++ return cid;
++}
++
++static inline int mm_cid_get(struct rq *rq, struct mm_struct *mm)
++{
++ struct mm_cid __percpu *pcpu_cid = mm->pcpu_cid;
++ struct cpumask *cpumask;
++ int cid;
++
++ lockdep_assert_rq_held(rq);
++ cpumask = mm_cidmask(mm);
++ cid = __this_cpu_read(pcpu_cid->cid);
++ if (mm_cid_is_valid(cid)) {
++ mm_cid_snapshot_time(rq, mm);
++ return cid;
++ }
++ if (mm_cid_is_lazy_put(cid)) {
++ if (try_cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, &cid, MM_CID_UNSET))
++ __mm_cid_put(mm, mm_cid_clear_lazy_put(cid));
++ }
++ cid = __mm_cid_get(rq, mm);
++ __this_cpu_write(pcpu_cid->cid, cid);
++ return cid;
++}
++
++static inline void switch_mm_cid(struct rq *rq,
++ struct task_struct *prev,
++ struct task_struct *next)
++{
++ /*
++ * Provide a memory barrier between rq->curr store and load of
++ * {prev,next}->mm->pcpu_cid[cpu] on rq->curr->mm transition.
++ *
++ * Should be adapted if context_switch() is modified.
++ */
++ if (!next->mm) { // to kernel
++ /*
++ * user -> kernel transition does not guarantee a barrier, but
++ * we can use the fact that it performs an atomic operation in
++ * mmgrab().
++ */
++ if (prev->mm) // from user
++ smp_mb__after_mmgrab();
++ /*
++ * kernel -> kernel transition does not change rq->curr->mm
++ * state. It stays NULL.
++ */
++ } else { // to user
++ /*
++ * kernel -> user transition does not provide a barrier
++ * between rq->curr store and load of {prev,next}->mm->pcpu_cid[cpu].
++ * Provide it here.
++ */
++ if (!prev->mm) // from kernel
++ smp_mb();
++ /*
++ * user -> user transition guarantees a memory barrier through
++ * switch_mm() when current->mm changes. If current->mm is
++ * unchanged, no barrier is needed.
++ */
++ }
++ if (prev->mm_cid_active) {
++ mm_cid_snapshot_time(rq, prev->mm);
++ mm_cid_put_lazy(prev);
++ prev->mm_cid = -1;
++ }
++ if (next->mm_cid_active)
++ next->last_mm_cid = next->mm_cid = mm_cid_get(rq, next->mm);
++}
++
++#else
++static inline void switch_mm_cid(struct rq *rq, struct task_struct *prev, struct task_struct *next) { }
++static inline void sched_mm_cid_migrate_from(struct task_struct *t) { }
++static inline void sched_mm_cid_migrate_to(struct rq *dst_rq, struct task_struct *t, int src_cpu) { }
++static inline void task_tick_mm_cid(struct rq *rq, struct task_struct *curr) { }
++static inline void init_sched_mm_cid(struct task_struct *t) { }
++#endif
++
++#endif /* ALT_SCHED_H */
+diff --git a/kernel/sched/bmq.h b/kernel/sched/bmq.h
+new file mode 100644
+index 000000000000..840009dc1e8d
+--- /dev/null
++++ b/kernel/sched/bmq.h
+@@ -0,0 +1,99 @@
++#define ALT_SCHED_NAME "BMQ"
++
++/*
++ * BMQ only routines
++ */
++#define rq_switch_time(rq) ((rq)->clock - (rq)->last_ts_switch)
++#define boost_threshold(p) (sysctl_sched_base_slice >> ((14 - (p)->boost_prio) / 2))
++
++static inline void boost_task(struct task_struct *p)
++{
++ int limit;
++
++ switch (p->policy) {
++ case SCHED_NORMAL:
++ limit = -MAX_PRIORITY_ADJ;
++ break;
++ case SCHED_BATCH:
++ case SCHED_IDLE:
++ limit = 0;
++ break;
++ default:
++ return;
++ }
++
++ if (p->boost_prio > limit)
++ p->boost_prio--;
++}
++
++static inline void deboost_task(struct task_struct *p)
++{
++ if (p->boost_prio < MAX_PRIORITY_ADJ)
++ p->boost_prio++;
++}
++
++/*
++ * Common interfaces
++ */
++static inline void sched_timeslice_imp(const int timeslice_ms) {}
++
++static inline int
++task_sched_prio_normal(const struct task_struct *p, const struct rq *rq)
++{
++ return p->prio + p->boost_prio - MAX_RT_PRIO;
++}
++
++static inline int task_sched_prio(const struct task_struct *p)
++{
++ return (p->prio < MAX_RT_PRIO)? (p->prio >> 2) :
++ MIN_SCHED_NORMAL_PRIO + (p->prio + p->boost_prio - MAX_RT_PRIO) / 2;
++}
++
++static inline int
++task_sched_prio_idx(const struct task_struct *p, const struct rq *rq)
++{
++ return task_sched_prio(p);
++}
++
++static inline int sched_prio2idx(int prio, struct rq *rq)
++{
++ return prio;
++}
++
++static inline int sched_idx2prio(int idx, struct rq *rq)
++{
++ return idx;
++}
++
++inline int task_running_nice(struct task_struct *p)
++{
++ return (p->prio + p->boost_prio > DEFAULT_PRIO + MAX_PRIORITY_ADJ);
++}
++
++static inline void sched_update_rq_clock(struct rq *rq) {}
++
++static inline void sched_task_renew(struct task_struct *p, const struct rq *rq)
++{
++ if (rq_switch_time(rq) > sysctl_sched_base_slice)
++ deboost_task(p);
++}
++
++static inline void sched_task_sanity_check(struct task_struct *p, struct rq *rq) {}
++static void sched_task_fork(struct task_struct *p, struct rq *rq) {}
++
++static inline void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
++{
++ p->boost_prio = MAX_PRIORITY_ADJ;
++}
++
++static inline void sched_task_ttwu(struct task_struct *p)
++{
++ if(this_rq()->clock_task - p->last_ran > sysctl_sched_base_slice)
++ boost_task(p);
++}
++
++static inline void sched_task_deactivate(struct task_struct *p, struct rq *rq)
++{
++ if (rq_switch_time(rq) < boost_threshold(p))
++ boost_task(p);
++}
+diff --git a/kernel/sched/build_policy.c b/kernel/sched/build_policy.c
+index d9dc9ab3773f..71a25540d65e 100644
+--- a/kernel/sched/build_policy.c
++++ b/kernel/sched/build_policy.c
+@@ -42,13 +42,19 @@
+
+ #include "idle.c"
+
++#ifndef CONFIG_SCHED_ALT
+ #include "rt.c"
++#endif
+
+ #ifdef CONFIG_SMP
++#ifndef CONFIG_SCHED_ALT
+ # include "cpudeadline.c"
++#endif
+ # include "pelt.c"
+ #endif
+
+ #include "cputime.c"
+-#include "deadline.c"
+
++#ifndef CONFIG_SCHED_ALT
++#include "deadline.c"
++#endif
+diff --git a/kernel/sched/build_utility.c b/kernel/sched/build_utility.c
+index 80a3df49ab47..bc17d5a6fc41 100644
+--- a/kernel/sched/build_utility.c
++++ b/kernel/sched/build_utility.c
+@@ -84,7 +84,9 @@
+
+ #ifdef CONFIG_SMP
+ # include "cpupri.c"
++#ifndef CONFIG_SCHED_ALT
+ # include "stop_task.c"
++#endif
+ # include "topology.c"
+ #endif
+
+diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
+index 5888176354e2..6ab2534714f6 100644
+--- a/kernel/sched/cpufreq_schedutil.c
++++ b/kernel/sched/cpufreq_schedutil.c
+@@ -155,12 +155,18 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
+
+ static void sugov_get_util(struct sugov_cpu *sg_cpu)
+ {
+- unsigned long util = cpu_util_cfs_boost(sg_cpu->cpu);
+ struct rq *rq = cpu_rq(sg_cpu->cpu);
+
++#ifndef CONFIG_SCHED_ALT
++ unsigned long util = cpu_util_cfs_boost(sg_cpu->cpu);
++
+ sg_cpu->bw_dl = cpu_bw_dl(rq);
+ sg_cpu->util = effective_cpu_util(sg_cpu->cpu, util,
+ FREQUENCY_UTIL, NULL);
++#else
++ sg_cpu->bw_dl = 0;
++ sg_cpu->util = rq_load_util(rq, arch_scale_cpu_capacity(sg_cpu->cpu));
++#endif /* CONFIG_SCHED_ALT */
+ }
+
+ /**
+@@ -306,8 +312,10 @@ static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
+ */
+ static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
+ {
++#ifndef CONFIG_SCHED_ALT
+ if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
+ sg_cpu->sg_policy->limits_changed = true;
++#endif
+ }
+
+ static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
+@@ -636,6 +644,7 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
+ }
+
+ ret = sched_setattr_nocheck(thread, &attr);
++
+ if (ret) {
+ kthread_stop(thread);
+ pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index af7952f12e6c..6461cbbb734d 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -126,7 +126,7 @@ void account_user_time(struct task_struct *p, u64 cputime)
+ p->utime += cputime;
+ account_group_user_time(p, cputime);
+
+- index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
++ index = task_running_nice(p) ? CPUTIME_NICE : CPUTIME_USER;
+
+ /* Add user time to cpustat. */
+ task_group_account_field(p, index, cputime);
+@@ -150,7 +150,7 @@ void account_guest_time(struct task_struct *p, u64 cputime)
+ p->gtime += cputime;
+
+ /* Add guest time to cpustat. */
+- if (task_nice(p) > 0) {
++ if (task_running_nice(p)) {
+ task_group_account_field(p, CPUTIME_NICE, cputime);
+ cpustat[CPUTIME_GUEST_NICE] += cputime;
+ } else {
+@@ -288,7 +288,7 @@ static inline u64 account_other_time(u64 max)
+ #ifdef CONFIG_64BIT
+ static inline u64 read_sum_exec_runtime(struct task_struct *t)
+ {
+- return t->se.sum_exec_runtime;
++ return tsk_seruntime(t);
+ }
+ #else
+ static u64 read_sum_exec_runtime(struct task_struct *t)
+@@ -298,7 +298,7 @@ static u64 read_sum_exec_runtime(struct task_struct *t)
+ struct rq *rq;
+
+ rq = task_rq_lock(t, &rf);
+- ns = t->se.sum_exec_runtime;
++ ns = tsk_seruntime(t);
+ task_rq_unlock(rq, t, &rf);
+
+ return ns;
+@@ -630,7 +630,7 @@ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+ void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+ {
+ struct task_cputime cputime = {
+- .sum_exec_runtime = p->se.sum_exec_runtime,
++ .sum_exec_runtime = tsk_seruntime(p),
+ };
+
+ if (task_cputime(p, &cputime.utime, &cputime.stime))
+diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
+index 4580a450700e..8c8fd7da4617 100644
+--- a/kernel/sched/debug.c
++++ b/kernel/sched/debug.c
+@@ -7,6 +7,7 @@
+ * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
+ */
+
++#ifndef CONFIG_SCHED_ALT
+ /*
+ * This allows printing both to /sys/kernel/debug/sched/debug and
+ * to the console
+@@ -215,6 +216,7 @@ static const struct file_operations sched_scaling_fops = {
+ };
+
+ #endif /* SMP */
++#endif /* !CONFIG_SCHED_ALT */
+
+ #ifdef CONFIG_PREEMPT_DYNAMIC
+
+@@ -278,6 +280,7 @@ static const struct file_operations sched_dynamic_fops = {
+
+ #endif /* CONFIG_PREEMPT_DYNAMIC */
+
++#ifndef CONFIG_SCHED_ALT
+ __read_mostly bool sched_debug_verbose;
+
+ #ifdef CONFIG_SMP
+@@ -332,6 +335,7 @@ static const struct file_operations sched_debug_fops = {
+ .llseek = seq_lseek,
+ .release = seq_release,
+ };
++#endif /* !CONFIG_SCHED_ALT */
+
+ static struct dentry *debugfs_sched;
+
+@@ -341,14 +345,17 @@ static __init int sched_init_debug(void)
+
+ debugfs_sched = debugfs_create_dir("sched", NULL);
+
++#ifndef CONFIG_SCHED_ALT
+ debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops);
+ debugfs_create_file_unsafe("verbose", 0644, debugfs_sched, &sched_debug_verbose, &sched_verbose_fops);
++#endif /* !CONFIG_SCHED_ALT */
+ #ifdef CONFIG_PREEMPT_DYNAMIC
+ debugfs_create_file("preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
+ #endif
+
+ debugfs_create_u32("base_slice_ns", 0644, debugfs_sched, &sysctl_sched_base_slice);
+
++#ifndef CONFIG_SCHED_ALT
+ debugfs_create_u32("latency_warn_ms", 0644, debugfs_sched, &sysctl_resched_latency_warn_ms);
+ debugfs_create_u32("latency_warn_once", 0644, debugfs_sched, &sysctl_resched_latency_warn_once);
+
+@@ -373,11 +380,13 @@ static __init int sched_init_debug(void)
+ #endif
+
+ debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
++#endif /* !CONFIG_SCHED_ALT */
+
+ return 0;
+ }
+ late_initcall(sched_init_debug);
+
++#ifndef CONFIG_SCHED_ALT
+ #ifdef CONFIG_SMP
+
+ static cpumask_var_t sd_sysctl_cpus;
+@@ -1106,6 +1115,7 @@ void proc_sched_set_task(struct task_struct *p)
+ memset(&p->stats, 0, sizeof(p->stats));
+ #endif
+ }
++#endif /* !CONFIG_SCHED_ALT */
+
+ void resched_latency_warn(int cpu, u64 latency)
+ {
+diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
+index 565f8374ddbb..67d51e05a8ac 100644
+--- a/kernel/sched/idle.c
++++ b/kernel/sched/idle.c
+@@ -380,6 +380,7 @@ void cpu_startup_entry(enum cpuhp_state state)
+ do_idle();
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ /*
+ * idle-task scheduling class.
+ */
+@@ -501,3 +502,4 @@ DEFINE_SCHED_CLASS(idle) = {
+ .switched_to = switched_to_idle,
+ .update_curr = update_curr_idle,
+ };
++#endif
+diff --git a/kernel/sched/pds.h b/kernel/sched/pds.h
+new file mode 100644
+index 000000000000..c35dfb909f23
+--- /dev/null
++++ b/kernel/sched/pds.h
+@@ -0,0 +1,141 @@
++#define ALT_SCHED_NAME "PDS"
++
++static const u64 RT_MASK = ((1ULL << MIN_SCHED_NORMAL_PRIO) - 1);
++
++#define SCHED_NORMAL_PRIO_NUM (32)
++#define SCHED_EDGE_DELTA (SCHED_NORMAL_PRIO_NUM - NICE_WIDTH / 2)
++
++/* PDS assume NORMAL_PRIO_NUM is power of 2 */
++#define SCHED_NORMAL_PRIO_MOD(x) ((x) & (SCHED_NORMAL_PRIO_NUM - 1))
++
++/* default time slice 4ms -> shift 22, 2 time slice slots -> shift 23 */
++static __read_mostly int sched_timeslice_shift = 23;
++
++/*
++ * Common interfaces
++ */
++static inline void sched_timeslice_imp(const int timeslice_ms)
++{
++ if (2 == timeslice_ms)
++ sched_timeslice_shift = 22;
++}
++
++static inline int
++task_sched_prio_normal(const struct task_struct *p, const struct rq *rq)
++{
++ s64 delta = p->deadline - rq->time_edge + SCHED_EDGE_DELTA;
++
++#ifdef ALT_SCHED_DEBUG
++ if (WARN_ONCE(delta > NORMAL_PRIO_NUM - 1,
++ "pds: task_sched_prio_normal() delta %lld\n", delta))
++ return SCHED_NORMAL_PRIO_NUM - 1;
++#endif
++
++ return max(0LL, delta);
++}
++
++static inline int task_sched_prio(const struct task_struct *p)
++{
++ return (p->prio < MIN_NORMAL_PRIO) ? (p->prio >> 2) :
++ MIN_SCHED_NORMAL_PRIO + task_sched_prio_normal(p, task_rq(p));
++}
++
++static inline int
++task_sched_prio_idx(const struct task_struct *p, const struct rq *rq)
++{
++ u64 idx;
++
++ if (p->prio < MIN_NORMAL_PRIO)
++ return p->prio >> 2;
++
++ idx = max(p->deadline + SCHED_EDGE_DELTA, rq->time_edge);
++ /*printk(KERN_INFO "sched: task_sched_prio_idx edge:%llu, deadline=%llu idx=%llu\n", rq->time_edge, p->deadline, idx);*/
++ return MIN_SCHED_NORMAL_PRIO + SCHED_NORMAL_PRIO_MOD(idx);
++}
++
++static inline int sched_prio2idx(int sched_prio, struct rq *rq)
++{
++ return (IDLE_TASK_SCHED_PRIO == sched_prio || sched_prio < MIN_SCHED_NORMAL_PRIO) ?
++ sched_prio :
++ MIN_SCHED_NORMAL_PRIO + SCHED_NORMAL_PRIO_MOD(sched_prio + rq->time_edge);
++}
++
++static inline int sched_idx2prio(int sched_idx, struct rq *rq)
++{
++ return (sched_idx < MIN_SCHED_NORMAL_PRIO) ?
++ sched_idx :
++ MIN_SCHED_NORMAL_PRIO + SCHED_NORMAL_PRIO_MOD(sched_idx - rq->time_edge);
++}
++
++int task_running_nice(struct task_struct *p)
++{
++ return (p->prio > DEFAULT_PRIO);
++}
++
++static inline void sched_update_rq_clock(struct rq *rq)
++{
++ struct list_head head;
++ u64 old = rq->time_edge;
++ u64 now = rq->clock >> sched_timeslice_shift;
++ u64 prio, delta;
++ DECLARE_BITMAP(normal, SCHED_QUEUE_BITS);
++
++ if (now == old)
++ return;
++
++ rq->time_edge = now;
++ delta = min_t(u64, SCHED_NORMAL_PRIO_NUM, now - old);
++ INIT_LIST_HEAD(&head);
++
++ prio = MIN_SCHED_NORMAL_PRIO;
++ for_each_set_bit_from(prio, rq->queue.bitmap, MIN_SCHED_NORMAL_PRIO + delta)
++ list_splice_tail_init(rq->queue.heads + MIN_SCHED_NORMAL_PRIO +
++ SCHED_NORMAL_PRIO_MOD(prio + old), &head);
++
++ bitmap_shift_right(normal, rq->queue.bitmap, delta, SCHED_QUEUE_BITS);
++ if (!list_empty(&head)) {
++ struct task_struct *p;
++ u64 idx = MIN_SCHED_NORMAL_PRIO + SCHED_NORMAL_PRIO_MOD(now);
++
++ list_for_each_entry(p, &head, sq_node)
++ p->sq_idx = idx;
++
++ list_splice(&head, rq->queue.heads + idx);
++ set_bit(MIN_SCHED_NORMAL_PRIO, normal);
++ }
++ bitmap_replace(rq->queue.bitmap, normal, rq->queue.bitmap,
++ (const unsigned long *)&RT_MASK, SCHED_QUEUE_BITS);
++
++ if (rq->prio < MIN_SCHED_NORMAL_PRIO || IDLE_TASK_SCHED_PRIO == rq->prio)
++ return;
++
++ rq->prio = (rq->prio < MIN_SCHED_NORMAL_PRIO + delta) ?
++ MIN_SCHED_NORMAL_PRIO : rq->prio - delta;
++}
++
++static inline void sched_task_renew(struct task_struct *p, const struct rq *rq)
++{
++ if (p->prio >= MIN_NORMAL_PRIO)
++ p->deadline = rq->time_edge + (p->static_prio - (MAX_PRIO - NICE_WIDTH)) / 2;
++}
++
++static inline void sched_task_sanity_check(struct task_struct *p, struct rq *rq)
++{
++ u64 max_dl = rq->time_edge + NICE_WIDTH / 2 - 1;
++ if (unlikely(p->deadline > max_dl))
++ p->deadline = max_dl;
++}
++
++static void sched_task_fork(struct task_struct *p, struct rq *rq)
++{
++ sched_task_renew(p, rq);
++}
++
++static inline void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
++{
++ p->time_slice = sysctl_sched_base_slice;
++ sched_task_renew(p, rq);
++}
++
++static inline void sched_task_ttwu(struct task_struct *p) {}
++static inline void sched_task_deactivate(struct task_struct *p, struct rq *rq) {}
+diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
+index 63b6cf898220..9ca10ece4d3a 100644
+--- a/kernel/sched/pelt.c
++++ b/kernel/sched/pelt.c
+@@ -266,6 +266,7 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load)
+ WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ /*
+ * sched_entity:
+ *
+@@ -383,8 +384,9 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+
+ return 0;
+ }
++#endif
+
+-#ifdef CONFIG_SCHED_THERMAL_PRESSURE
++#if defined(CONFIG_SCHED_THERMAL_PRESSURE) && !defined(CONFIG_SCHED_ALT)
+ /*
+ * thermal:
+ *
+diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
+index 3a0e0dc28721..e8a7d84aa5a5 100644
+--- a/kernel/sched/pelt.h
++++ b/kernel/sched/pelt.h
+@@ -1,13 +1,15 @@
+ #ifdef CONFIG_SMP
+ #include "sched-pelt.h"
+
++#ifndef CONFIG_SCHED_ALT
+ int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
+ int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
+ int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
+ int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
+ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
++#endif
+
+-#ifdef CONFIG_SCHED_THERMAL_PRESSURE
++#if defined(CONFIG_SCHED_THERMAL_PRESSURE) && !defined(CONFIG_SCHED_ALT)
+ int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
+
+ static inline u64 thermal_load_avg(struct rq *rq)
+@@ -44,6 +46,7 @@ static inline u32 get_pelt_divider(struct sched_avg *avg)
+ return PELT_MIN_DIVIDER + avg->period_contrib;
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ static inline void cfs_se_util_change(struct sched_avg *avg)
+ {
+ unsigned int enqueued;
+@@ -180,9 +183,11 @@ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+ return rq_clock_pelt(rq_of(cfs_rq));
+ }
+ #endif
++#endif /* CONFIG_SCHED_ALT */
+
+ #else
+
++#ifndef CONFIG_SCHED_ALT
+ static inline int
+ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+ {
+@@ -200,6 +205,7 @@ update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+ {
+ return 0;
+ }
++#endif
+
+ static inline int
+ update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index 2e5a95486a42..0c86131a2a64 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -5,6 +5,10 @@
+ #ifndef _KERNEL_SCHED_SCHED_H
+ #define _KERNEL_SCHED_SCHED_H
+
++#ifdef CONFIG_SCHED_ALT
++#include "alt_sched.h"
++#else
++
+ #include <linux/sched/affinity.h>
+ #include <linux/sched/autogroup.h>
+ #include <linux/sched/cpufreq.h>
+@@ -3509,4 +3513,9 @@ static inline void init_sched_mm_cid(struct task_struct *t) { }
+ extern u64 avg_vruntime(struct cfs_rq *cfs_rq);
+ extern int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se);
+
++static inline int task_running_nice(struct task_struct *p)
++{
++ return (task_nice(p) > 0);
++}
++#endif /* !CONFIG_SCHED_ALT */
+ #endif /* _KERNEL_SCHED_SCHED_H */
+diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
+index 857f837f52cb..5486c63e4790 100644
+--- a/kernel/sched/stats.c
++++ b/kernel/sched/stats.c
+@@ -125,8 +125,10 @@ static int show_schedstat(struct seq_file *seq, void *v)
+ } else {
+ struct rq *rq;
+ #ifdef CONFIG_SMP
++#ifndef CONFIG_SCHED_ALT
+ struct sched_domain *sd;
+ int dcount = 0;
++#endif
+ #endif
+ cpu = (unsigned long)(v - 2);
+ rq = cpu_rq(cpu);
+@@ -143,6 +145,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
+ seq_printf(seq, "\n");
+
+ #ifdef CONFIG_SMP
++#ifndef CONFIG_SCHED_ALT
+ /* domain-specific stats */
+ rcu_read_lock();
+ for_each_domain(cpu, sd) {
+@@ -171,6 +174,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
+ sd->ttwu_move_balance);
+ }
+ rcu_read_unlock();
++#endif
+ #endif
+ }
+ return 0;
+diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
+index 38f3698f5e5b..b9d597394316 100644
+--- a/kernel/sched/stats.h
++++ b/kernel/sched/stats.h
+@@ -89,6 +89,7 @@ static inline void rq_sched_info_depart (struct rq *rq, unsigned long long delt
+
+ #endif /* CONFIG_SCHEDSTATS */
+
++#ifndef CONFIG_SCHED_ALT
+ #ifdef CONFIG_FAIR_GROUP_SCHED
+ struct sched_entity_stats {
+ struct sched_entity se;
+@@ -105,6 +106,7 @@ __schedstats_from_se(struct sched_entity *se)
+ #endif
+ return &task_of(se)->stats;
+ }
++#endif /* CONFIG_SCHED_ALT */
+
+ #ifdef CONFIG_PSI
+ void psi_task_change(struct task_struct *task, int clear, int set);
+diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
+index 10d1391e7416..120933a5b206 100644
+--- a/kernel/sched/topology.c
++++ b/kernel/sched/topology.c
+@@ -3,6 +3,7 @@
+ * Scheduler topology setup/handling methods
+ */
+
++#ifndef CONFIG_SCHED_ALT
+ #include <linux/bsearch.h>
+
+ DEFINE_MUTEX(sched_domains_mutex);
+@@ -1445,8 +1446,10 @@ static void asym_cpu_capacity_scan(void)
+ */
+
+ static int default_relax_domain_level = -1;
++#endif /* CONFIG_SCHED_ALT */
+ int sched_domain_level_max;
+
++#ifndef CONFIG_SCHED_ALT
+ static int __init setup_relax_domain_level(char *str)
+ {
+ if (kstrtoint(str, 0, &default_relax_domain_level))
+@@ -1680,6 +1683,7 @@ sd_init(struct sched_domain_topology_level *tl,
+
+ return sd;
+ }
++#endif /* CONFIG_SCHED_ALT */
+
+ /*
+ * Topology list, bottom-up.
+@@ -1716,6 +1720,7 @@ void __init set_sched_topology(struct sched_domain_topology_level *tl)
+ sched_domain_topology_saved = NULL;
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ #ifdef CONFIG_NUMA
+
+ static const struct cpumask *sd_numa_mask(int cpu)
+@@ -2793,3 +2798,20 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
+ mutex_unlock(&sched_domains_mutex);
+ }
++#else /* CONFIG_SCHED_ALT */
++void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
++ struct sched_domain_attr *dattr_new)
++{}
++
++#ifdef CONFIG_NUMA
++int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
++{
++ return best_mask_cpu(cpu, cpus);
++}
++
++int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
++{
++ return cpumask_nth(cpu, cpus);
++}
++#endif /* CONFIG_NUMA */
++#endif
+diff --git a/kernel/sysctl.c b/kernel/sysctl.c
+index 157f7ce2942d..63083a9a2935 100644
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -92,6 +92,10 @@ EXPORT_SYMBOL_GPL(sysctl_long_vals);
+
+ /* Constants used for minimum and maximum */
+
++#ifdef CONFIG_SCHED_ALT
++extern int sched_yield_type;
++#endif
++
+ #ifdef CONFIG_PERF_EVENTS
+ static const int six_hundred_forty_kb = 640 * 1024;
+ #endif
+@@ -1912,6 +1916,17 @@ static struct ctl_table kern_table[] = {
+ .proc_handler = proc_dointvec,
+ },
+ #endif
++#ifdef CONFIG_SCHED_ALT
++ {
++ .procname = "yield_type",
++ .data = &sched_yield_type,
++ .maxlen = sizeof (int),
++ .mode = 0644,
++ .proc_handler = &proc_dointvec_minmax,
++ .extra1 = SYSCTL_ZERO,
++ .extra2 = SYSCTL_TWO,
++ },
++#endif
+ #if defined(CONFIG_S390) && defined(CONFIG_SMP)
+ {
+ .procname = "spin_retry",
+diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
+index 760793998cdd..3198ed8ab40a 100644
+--- a/kernel/time/hrtimer.c
++++ b/kernel/time/hrtimer.c
+@@ -2091,8 +2091,10 @@ long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
+ int ret = 0;
+ u64 slack;
+
++#ifndef CONFIG_SCHED_ALT
+ slack = current->timer_slack_ns;
+- if (rt_task(current))
++ if (dl_task(current) || rt_task(current))
++#endif
+ slack = 0;
+
+ hrtimer_init_sleeper_on_stack(&t, clockid, mode);
+diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
+index e9c6f9d0e42c..43ee0a94abdd 100644
+--- a/kernel/time/posix-cpu-timers.c
++++ b/kernel/time/posix-cpu-timers.c
+@@ -223,7 +223,7 @@ static void task_sample_cputime(struct task_struct *p, u64 *samples)
+ u64 stime, utime;
+
+ task_cputime(p, &utime, &stime);
+- store_samples(samples, stime, utime, p->se.sum_exec_runtime);
++ store_samples(samples, stime, utime, tsk_seruntime(p));
+ }
+
+ static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
+@@ -867,6 +867,7 @@ static void collect_posix_cputimers(struct posix_cputimers *pct, u64 *samples,
+ }
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ static inline void check_dl_overrun(struct task_struct *tsk)
+ {
+ if (tsk->dl.dl_overrun) {
+@@ -874,6 +875,7 @@ static inline void check_dl_overrun(struct task_struct *tsk)
+ send_signal_locked(SIGXCPU, SEND_SIG_PRIV, tsk, PIDTYPE_TGID);
+ }
+ }
++#endif
+
+ static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
+ {
+@@ -901,8 +903,10 @@ static void check_thread_timers(struct task_struct *tsk,
+ u64 samples[CPUCLOCK_MAX];
+ unsigned long soft;
+
++#ifndef CONFIG_SCHED_ALT
+ if (dl_task(tsk))
+ check_dl_overrun(tsk);
++#endif
+
+ if (expiry_cache_is_inactive(pct))
+ return;
+@@ -916,7 +920,7 @@ static void check_thread_timers(struct task_struct *tsk,
+ soft = task_rlimit(tsk, RLIMIT_RTTIME);
+ if (soft != RLIM_INFINITY) {
+ /* Task RT timeout is accounted in jiffies. RTTIME is usec */
+- unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
++ unsigned long rttime = tsk_rttimeout(tsk) * (USEC_PER_SEC / HZ);
+ unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
+
+ /* At the hard limit, send SIGKILL. No further action. */
+@@ -1152,8 +1156,10 @@ static inline bool fastpath_timer_check(struct task_struct *tsk)
+ return true;
+ }
+
++#ifndef CONFIG_SCHED_ALT
+ if (dl_task(tsk) && tsk->dl.dl_overrun)
+ return true;
++#endif
+
+ return false;
+ }
+diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
+index 529590499b1f..d04bb99b4f0e 100644
+--- a/kernel/trace/trace_selftest.c
++++ b/kernel/trace/trace_selftest.c
+@@ -1155,10 +1155,15 @@ static int trace_wakeup_test_thread(void *data)
+ {
+ /* Make this a -deadline thread */
+ static const struct sched_attr attr = {
++#ifdef CONFIG_SCHED_ALT
++ /* No deadline on BMQ/PDS, use RR */
++ .sched_policy = SCHED_RR,
++#else
+ .sched_policy = SCHED_DEADLINE,
+ .sched_runtime = 100000ULL,
+ .sched_deadline = 10000000ULL,
+ .sched_period = 10000000ULL
++#endif
+ };
+ struct wakeup_test_data *x = data;
+
+diff --git a/kernel/workqueue.c b/kernel/workqueue.c
+index 2989b57e154a..7313d9f5585f 100644
+--- a/kernel/workqueue.c
++++ b/kernel/workqueue.c
+@@ -1114,6 +1114,7 @@ static bool kick_pool(struct worker_pool *pool)
+
+ p = worker->task;
+
++#ifndef CONFIG_SCHED_ALT
+ #ifdef CONFIG_SMP
+ /*
+ * Idle @worker is about to execute @work and waking up provides an
+@@ -1139,6 +1140,8 @@ static bool kick_pool(struct worker_pool *pool)
+ get_work_pwq(work)->stats[PWQ_STAT_REPATRIATED]++;
+ }
+ #endif
++#endif /* !CONFIG_SCHED_ALT */
++
+ wake_up_process(p);
+ return true;
+ }
+@@ -1263,7 +1266,11 @@ void wq_worker_running(struct task_struct *task)
+ * CPU intensive auto-detection cares about how long a work item hogged
+ * CPU without sleeping. Reset the starting timestamp on wakeup.
+ */
++#ifdef CONFIG_SCHED_ALT
++ worker->current_at = worker->task->sched_time;
++#else
+ worker->current_at = worker->task->se.sum_exec_runtime;
++#endif
+
+ WRITE_ONCE(worker->sleeping, 0);
+ }
+@@ -1348,7 +1355,11 @@ void wq_worker_tick(struct task_struct *task)
+ * We probably want to make this prettier in the future.
+ */
+ if ((worker->flags & WORKER_NOT_RUNNING) || READ_ONCE(worker->sleeping) ||
++#ifdef CONFIG_SCHED_ALT
++ worker->task->sched_time - worker->current_at <
++#else
+ worker->task->se.sum_exec_runtime - worker->current_at <
++#endif
+ wq_cpu_intensive_thresh_us * NSEC_PER_USEC)
+ return;
+
+@@ -2559,7 +2570,11 @@ __acquires(&pool->lock)
+ worker->current_work = work;
+ worker->current_func = work->func;
+ worker->current_pwq = pwq;
++#ifdef CONFIG_SCHED_ALT
++ worker->current_at = worker->task->sched_time;
++#else
+ worker->current_at = worker->task->se.sum_exec_runtime;
++#endif
+ work_data = *work_data_bits(work);
+ worker->current_color = get_work_color(work_data);
+
+From 58a9cabf63a961c5fc501cf1ade12e1dc6029642 Mon Sep 17 00:00:00 2001
+From: Steven Barrett <steven@liquorix.net>
+Date: Sun, 28 Jan 2024 10:22:43 -0600
+Subject: [PATCH] sched/alt: [Sync] 9feae65845f7 sched/topology: Introduce
+ sched_numa_hop_mask()
+
+---
+ kernel/sched/topology.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
+index 120933a5b206..dc717683342e 100644
+--- a/kernel/sched/topology.c
++++ b/kernel/sched/topology.c
+@@ -2813,5 +2813,11 @@ int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
+ {
+ return cpumask_nth(cpu, cpus);
+ }
++
++const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops)
++{
++ return ERR_PTR(-EOPNOTSUPP);
++}
++EXPORT_SYMBOL_GPL(sched_numa_hop_mask);
+ #endif /* CONFIG_NUMA */
+ #endif