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Diffstat (limited to 'SOURCES/0001-kdump-add-support-for-crashkernel-auto.patch')
| -rw-r--r-- | SOURCES/0001-kdump-add-support-for-crashkernel-auto.patch | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/SOURCES/0001-kdump-add-support-for-crashkernel-auto.patch b/SOURCES/0001-kdump-add-support-for-crashkernel-auto.patch new file mode 100644 index 0000000..83eb38e --- /dev/null +++ b/SOURCES/0001-kdump-add-support-for-crashkernel-auto.patch @@ -0,0 +1,189 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Jeremy Cline <jcline@redhat.com> +Date: Tue, 23 Jul 2019 15:24:30 +0000 +Subject: [PATCH] kdump: add support for crashkernel=auto + +Rebased for v5.3-rc1 because the documentation has moved. + + Message-id: <20180604013831.574215750@redhat.com> + Patchwork-id: 8166 + O-Subject: [kernel team] [PATCH RHEL8.0 V2 2/2] kdump: add support for crashkernel=auto + Bugzilla: 1507353 + RH-Acked-by: Don Zickus <dzickus@redhat.com> + RH-Acked-by: Baoquan He <bhe@redhat.com> + RH-Acked-by: Pingfan Liu <piliu@redhat.com> + + Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1507353 + Build: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=16534135 + Tested: ppc64le, x86_64 with several memory sizes. + kdump qe tested 160M on various x86 machines in lab. + + We continue to provide crashkernel=auto like we did in RHEL6 + and RHEL7, this will simplify the kdump deployment for common + use cases that kdump just works with the auto reserved values. + But this is still a best effort estimation, we can not know the + exact memory requirement because it depends on a lot of different + factors. + + The implementation of crashkernel=auto is simplified as a wrapper + to use below kernel cmdline: + x86_64: crashkernel=1G-64G:160M,64G-1T:256M,1T-:512M + s390x: crashkernel=4G-64G:160M,64G-1T:256M,1T-:512M + arm64: crashkernel=2G-:512M + ppc64: crashkernel=2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G + + The difference between this way and the old implementation in + RHEL6/7 is we do not scale the crash reserved memory size according + to system memory size anymore. + + Latest effort to move upstream is below thread: + https://lkml.org/lkml/2018/5/20/262 + But unfortunately it is still unlikely to be accepted, thus we + will still use a RHEL only patch in RHEL8. + + Copied old patch description about the history reason see below: + ''' + Non-upstream explanations: + Besides "crashkenrel=X@Y" format, upstream also has advanced + "crashkernel=range1:size1[,range2:size2,...][@offset]", and + "crashkernel=X,high{low}" formats, but they need more careful + manual configuration, and have different values for different + architectures. + + Most of the distributions use the standard "crashkernel=X@Y" + upstream format, and use crashkernel range format for advanced + scenarios, heavily relying on the user's involvement. + + While "crashkernel=auto" is redhat's special feature, it exists + and has been used as the default boot cmdline since 2008 rhel6. + It does not require users to figure out how many crash memory + size for their systems, also has been proved to be able to work + pretty well for common scenarios. + + "crashkernel=auto" was tested/based on rhel-related products, as + we have stable kernel configurations which means more or less + stable memory consumption. In 2014 we tried to post them again to + upstream but NACKed by people because they think it's not general + and unnecessary, users can specify their own values or do that by + scripts. However our customers insist on having it added to rhel. + + Also see one previous discussion related to this backport to Pegas: + On 10/17/2016 at 10:15 PM, Don Zickus wrote: + > On Fri, Oct 14, 2016 at 10:57:41AM +0800, Dave Young wrote: + >> Don, agree with you we should evaluate them instead of just inherit + >> them blindly. Below is what I think about kdump auto memory: + >> There are two issues for crashkernel=auto in upstream: + >> 1) It will be seen as a policy which should not go to kernel + >> 2) It is hard to get a good number for the crash reserved size, + >> considering various different kernel config options one can setups. + >> In RHEL we are easier because our supported Kconfig is limited. + >> I digged the upstream mail archive, but I'm not sure I got all the + >> information, at least Michael Ellerman was objecting the series for + >> 1). + > Yes, I know. Vivek and I have argued about this for years. :-) + > + > I had hoped all the changes internally to the makedumpfile would allow + > the memory configuration to stabilize at a number like 192M or 128M and + > only in the rare cases extend beyond that. + > + > So I always treated that as a temporary hack until things were better. + > With the hope of every new RHEL release we get smarter and better. :-) + > Ideally it would be great if we could get the number down to 64M for most + > cases and just turn it on in Fedora. Maybe someday.... ;-) + > + > We can have this conversation when the patch gets reposted/refreshed + > for upstream on rhkl? + > + > Cheers, + > Don + + We had proposed to drop the historic crashkernel=auto code and move + to use crashkernel=range:size format and pass them in anaconda. + + The initial reason is crashkernel=range:size works just fine because + we do not need complex algorithm to scale crashkernel reserved size + any more. The old linear scaling is mainly for old makedumpfile + requirements, now it is not necessary. + + But With the new approach, backward compatibility is potentially at risk. + For e.g. let's consider the following cases: + 1) When we upgrade from an older distribution like rhel-alt-7.4(which + uses crashkernel=auto) to rhel-alt-7.5 (which uses the crashkernel=xY + format) + In this case we can use anaconda scripts for checking + 'crashkernel=auto' in kernel spec and update to the new + 'crashkernel=range:size' format. + 2) When we upgrade from rhel-alt-7.5(which uses crashkernel=xY format) + to rhel-alt-7.6(which uses crashkernel=xY format), but the x and/or Y + values are changed in rhel-alt-7.6. + For example from crashkernel=2G-:160M to crashkernel=2G-:192M, then we have + no way to determine if the X and/or Y values were distribution + provided or user specified ones. + Since it is recommended to give precedence to user-specified values, + so we cannot do an upgrade in such a case." + + Thus turn back to resolve it in kernel, and add a simpler version + which just hacks to use the range:size style in code, and make + rhel-only code easily to maintain. + ''' + + Signed-off-by: Dave Young <dyoung@redhat.com> + Signed-off-by: Herton R. Krzesinski <herton@redhat.com> + +Upstream Status: RHEL only +Signed-off-by: Jeremy Cline <jcline@redhat.com> +--- + Documentation/admin-guide/kdump/kdump.rst | 11 +++++++++++ + kernel/crash_core.c | 14 ++++++++++++++ + 2 files changed, 25 insertions(+) + +diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst +index ac7e131d2935..3b3bf30e537d 100644 +--- a/Documentation/admin-guide/kdump/kdump.rst ++++ b/Documentation/admin-guide/kdump/kdump.rst +@@ -285,6 +285,17 @@ This would mean: + 2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M + 3) if the RAM size is larger than 2G, then reserve 128M + ++Or you can use crashkernel=auto if you have enough memory. The threshold ++is 2G on x86_64, arm64, ppc64 and ppc64le. The threshold is 4G for s390x. ++If your system memory is less than the threshold crashkernel=auto will not ++reserve memory. ++ ++The automatically reserved memory size varies based on architecture. ++The size changes according to system memory size like below: ++ x86_64: 1G-64G:160M,64G-1T:256M,1T-:512M ++ s390x: 4G-64G:160M,64G-1T:256M,1T-:512M ++ arm64: 2G-:512M ++ ppc64: 2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G + + + Boot into System Kernel +diff --git a/kernel/crash_core.c b/kernel/crash_core.c +index d631d22089ba..c252221b2f4b 100644 +--- a/kernel/crash_core.c ++++ b/kernel/crash_core.c +@@ -258,6 +258,20 @@ static int __init __parse_crashkernel(char *cmdline, + if (suffix) + return parse_crashkernel_suffix(ck_cmdline, crash_size, + suffix); ++ ++ if (strncmp(ck_cmdline, "auto", 4) == 0) { ++#ifdef CONFIG_X86_64 ++ ck_cmdline = "1G-64G:160M,64G-1T:256M,1T-:512M"; ++#elif defined(CONFIG_S390) ++ ck_cmdline = "4G-64G:160M,64G-1T:256M,1T-:512M"; ++#elif defined(CONFIG_ARM64) ++ ck_cmdline = "2G-:512M"; ++#elif defined(CONFIG_PPC64) ++ ck_cmdline = "2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G"; ++#endif ++ pr_info("Using crashkernel=auto, the size choosed is a best effort estimation.\n"); ++ } ++ + /* + * if the commandline contains a ':', then that's the extended + * syntax -- if not, it must be the classic syntax +-- +2.26.2 + |