[PATCH v4 1/1] kernel/crash_core: Add crashkernel=auto for vmcore creation
STALE2042d
REVIEWED: 1 (0M)
From: Saeed Mirzamohammadi <hidden>
Date: 2021-02-23 17:45:07
Also in:
kexec, lkml
Subsystem:
documentation, kdump, the rest · Maintainers:
Jonathan Corbet, Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
1 review trailer.
This adds crashkernel=auto feature to configure reserved memory for vmcore creation. CONFIG_CRASH_AUTO_STR is defined to be set for different kernel distributions and different archs based on their needs. Signed-off-by: Saeed Mirzamohammadi <redacted> Signed-off-by: John Donnelly <redacted> Tested-by: John Donnelly <redacted> --- Documentation/admin-guide/kdump/kdump.rst | 3 ++- .../admin-guide/kernel-parameters.txt | 6 ++++++ arch/Kconfig | 20 +++++++++++++++++++ kernel/crash_core.c | 7 +++++++ 4 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
index 75a9dd98e76e..ae030111e22a 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst@@ -285,7 +285,8 @@ 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 to choose the crash kernel memory size +based on the recommended configuration set for each arch. Boot into System Kernel =======================
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9e3cdb271d06..a5deda5c85fe 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt@@ -747,6 +747,12 @@ a memory unit (amount[KMG]). See also Documentation/admin-guide/kdump/kdump.rst for an example. + crashkernel=auto + [KNL] This parameter will set the reserved memory for + the crash kernel based on the value of the CRASH_AUTO_STR + that is the best effort estimation for each arch. See also + arch/Kconfig for further details. + crashkernel=size[KMG],high [KNL, X86-64] range could be above 4G. Allow kernel to allocate physical memory region from top, so could
diff --git a/arch/Kconfig b/arch/Kconfig
index 24862d15f3a3..23d047548772 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig@@ -14,6 +14,26 @@ menu "General architecture-dependent options" config CRASH_CORE bool +config CRASH_AUTO_STR + string "Memory reserved for crash kernel" + depends on CRASH_CORE + default "1G-64G:128M,64G-1T:256M,1T-:512M" + help + This configures the reserved memory dependent + on the value of System RAM. The syntax is: + crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset] + range=start-[end] + + For example: + crashkernel=512M-2G:64M,2G-:128M + + This would mean: + + 1) if the RAM is smaller than 512M, then don't reserve anything + (this is the "rescue" case) + 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 + config KEXEC_CORE select CRASH_CORE bool
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 825284baaf46..90f9e4bb6704 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>
@@ -250,6 +251,12 @@ static int __init __parse_crashkernel(char *cmdline, if (suffix) return parse_crashkernel_suffix(ck_cmdline, crash_size, suffix); +#ifdef CONFIG_CRASH_AUTO_STR + if (strncmp(ck_cmdline, "auto", 4) == 0) { + ck_cmdline = CONFIG_CRASH_AUTO_STR; + pr_info("Using crashkernel=auto, the size chosen is a best effort estimation.\n"); + } +#endif /* * if the commandline contains a ':', then that's the extended * syntax -- if not, it must be the classic syntax
--
2.27.0