Messages in this thread Patch in this message | | | From | John Donnelly <> | Date | Wed, 4 Dec 2019 13:22:26 -0600 | Subject | [PATCH ] kernel/crash_core.c - Add crashkernel=auto for x86 and Arm |
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This adds crashkernel=auto feature to configure reserved memory for vmcore creation to both x86 and Arm platform as implemenented in RH 4.18.0-147.el8 kernels. The values have been adjusted for x86 and Arm based from 5.4.0 kernel crash testing.
Signed-off-by: John Donnelly <john.p.donnelly@oracle.com> Tested-by: John Donnelly <john.p.donnelly@oracle.com> --- Documentation/admin-guide/kdump/kdump.rst | 12 ++++++++++ kernel/crash_core.c | 28 +++++++++++++++++++++-- 2 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst index ac7e131d2935..7635bbb4ab34 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -285,6 +285,18 @@ 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 1G on x86_64, 2G on 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:280M,1T-:512M + s390x: 4G-64G:160M,64G-1T:256M,1T-:512M + arm64: 2G-:768M + 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 9f1557b98468..564aca60e57f 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -7,6 +7,7 @@ #include <linux/crash_core.h> #include <linux/utsname.h> #include <linux/vmalloc.h> +#include <linux/kexec.h> #include <asm/page.h> #include <asm/sections.h> @@ -39,6 +40,15 @@ static int __init parse_crashkernel_mem(char *cmdline, unsigned long long *crash_base) { char *cur = cmdline, *tmp; + unsigned long long total_mem = system_ram; + + /* + * Firmware sometimes reserves some memory regions for it's own use. + * so we get less than actual system memory size. + * Workaround this by round up the total size to 128M which is + * enough for most test cases. + */ + total_mem = roundup(total_mem, SZ_128M); /* for each entry of the comma-separated list */ do { @@ -83,13 +93,13 @@ static int __init parse_crashkernel_mem(char *cmdline, return -EINVAL; } cur = tmp; - if (size >= system_ram) { + if (size >= total_mem) { pr_warn("crashkernel: invalid size\n"); return -EINVAL; } /* match ? */ - if (system_ram >= start && system_ram < end) { + if (total_mem >= start && total_mem < end) { *crash_size = size; break; } @@ -248,6 +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:280M,1T-:512M"; +#elif defined(CONFIG_S390) + ck_cmdline = "4G-64G:160M,64G-1T:256M,1T-:512M"; +#elif defined(CONFIG_ARM64) + ck_cmdline = "2G-:768M"; +#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 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 -- 2.20.1 | |