From: Saeed Mirzamohammadi <saeed.mirzamohammadi@xxxxxxxxxx> Subject: kernel/crash_core: add crashkernel=auto for vmcore creation 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. Link: https://lkml.kernel.org/r/20210223174153.72802-1-saeed.mirzamohammadi@xxxxxxxxxx Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@xxxxxxxxxx> Signed-off-by: John Donnelly <john.p.donnelly@xxxxxxxxxx> Tested-by: John Donnelly <john.p.donnelly@xxxxxxxxxx> ed-by: Dave Young <dyoung@xxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: "Guilherme G. Piccoli" <gpiccoli@xxxxxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx> Cc: YiFei Zhu <yifeifz2@xxxxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxx> Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Cc: Frederic Weisbecker <frederic@xxxxxxxxxx> Cc: Christian Brauner <christian.brauner@xxxxxxxxxx> Cc: Stephen Boyd <sboyd@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Colin Ian King <colin.king@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/admin-guide/kdump/kdump.rst | 3 +- Documentation/admin-guide/kernel-parameters.txt | 6 ++++ arch/Kconfig | 20 ++++++++++++++ kernel/crash_core.c | 7 ++++ 4 files changed, 35 insertions(+), 1 deletion(-) --- a/arch/Kconfig~kernel-crash_core-add-crashkernel=auto-for-vmcore-creation +++ a/arch/Kconfig @@ -14,6 +14,26 @@ menu "General architecture-dependent opt 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 --- a/Documentation/admin-guide/kdump/kdump.rst~kernel-crash_core-add-crashkernel=auto-for-vmcore-creation +++ a/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 ======================= --- a/Documentation/admin-guide/kernel-parameters.txt~kernel-crash_core-add-crashkernel=auto-for-vmcore-creation +++ a/Documentation/admin-guide/kernel-parameters.txt @@ -751,6 +751,12 @@ 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 --- a/kernel/crash_core.c~kernel-crash_core-add-crashkernel=auto-for-vmcore-creation +++ a/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(ch 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 _
