Set the reserved memory automatically for the crash kernel based on architecture. Most code of this patch come from: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-8/-/tree/c8s Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> --- Documentation/admin-guide/kdump/kdump.rst | 13 +++++++++++++ Documentation/admin-guide/kernel-parameters.txt | 5 +++++ kernel/crash_core.c | 20 ++++++++++++++++++++ 3 files changed, 38 insertions(+) diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst index cb30ca3d..8f8a9cc 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -335,6 +335,19 @@ crashkernel syntax crashkernel=0,low +4) crashkernel=auto + + You can use crashkernel=auto if you have enough memory. The threshold + is 1G on x86_64 and s390x, 2G on arm64, ppc64 and ppc64le. 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-4G:160M,4G-64G:192M,64G-1T:256M,1T-:512M + s390x: 1G-4G:160M,4G-64G:192M,64G-1T:256M,1T-:512M + arm64: 2G-:448M + ppc64: 2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G + Boot into System Kernel ----------------------- 1) Update the boot loader (such as grub, yaboot, or lilo) configuration diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f5a27f0..14f052d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -783,6 +783,11 @@ Format: <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] + crashkernel=auto + [KNL] Set the reserved memory automatically for the crash kernel + based on architecture. + See Documentation/admin-guide/kdump/kdump.rst for further details. + crashkernel=size[KMG][@offset[KMG]] [KNL] Using kexec, Linux can switch to a 'crash kernel' upon panic. This parameter reserves the physical diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 256cf6d..32c51e2 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -252,6 +252,26 @@ 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) { +#if defined(CONFIG_X86_64) || defined(CONFIG_S390) + ck_cmdline = "1G-4G:160M,4G-64G:192M,64G-1T:256M,1T-:512M"; +#elif defined(CONFIG_ARM64) + ck_cmdline = "2G-:448M"; +#elif defined(CONFIG_PPC64) + char *fadump_cmdline; + + fadump_cmdline = get_last_crashkernel(cmdline, "fadump=", NULL); + fadump_cmdline = fadump_cmdline ? + fadump_cmdline + strlen("fadump=") : NULL; + if (!fadump_cmdline || (strncmp(fadump_cmdline, "off", 3) == 0)) + ck_cmdline = "2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G"; + else + ck_cmdline = "4G-16G:768M,16G-64G:1G,64G-128G:2G,128G-1T:4G,1T-2T:6G,2T-4T:12G,4T-8T:20G,8T-16T:36G,16T-32T:64G,32T-64T:128G,64T-:180G"; +#endif + pr_info("Using crashkernel=auto, the size chosen 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 -- 2.1.0
