Hi,
On 11/18/20 3:24 PM, Saeed Mirzamohammadi wrote:
> This adds crashkernel=auto feature to configure reserved memory for
> vmcore creation to both x86 and ARM platforms based on the total memory
> size.
>
> Cc: sta...@vger.kernel.org
why?
> Signed-off-by: John Donnelly <john.p.donne...@oracle.com>
> Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohamm...@oracle.com>
> ---
> Documentation/admin-guide/kdump/kdump.rst | 5 +++++
> arch/arm64/Kconfig | 26 ++++++++++++++++++++++-
> arch/arm64/configs/defconfig | 1 +
> arch/x86/Kconfig | 26 ++++++++++++++++++++++-
> arch/x86/configs/x86_64_defconfig | 1 +
> kernel/crash_core.c | 20 +++++++++++++++--
> 6 files changed, 75 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1515f6f153a0..d359dcffa80e 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1135,6 +1135,30 @@ config CRASH_DUMP
>
> For more details see Documentation/admin-guide/kdump/kdump.rst
>
> +if CRASH_DUMP
> +
> +config CRASH_AUTO_STR
> + string "Memory reserved for crash kernel"
use tab instead of spaces above.
> + depends on CRASH_DUMP
> + default "1G-64G:128M,64G-1T:256M,1T-:512M"
ditto.
> + 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
> +
> +endif # CRASH_DUMP
> +
> config XEN_DOM0
> def_bool y
> depends on XEN
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index f6946b81f74a..bacd17312bb1 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2049,6 +2049,30 @@ config CRASH_DUMP
> (CONFIG_RELOCATABLE=y).
> For more details see Documentation/admin-guide/kdump/kdump.rst
>
> +if CRASH_DUMP
> +
> +config CRASH_AUTO_STR
> + string "Memory reserved for crash kernel" if X86_64
ditto.
> + depends on CRASH_DUMP
> + default "1G-64G:128M,64G-1T:256M,1T-:512M"
ditto.
> + 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
> +
> +endif # CRASH_DUMP
> +
> config KEXEC_JUMP
> bool "kexec jump"
> depends on KEXEC && HIBERNATION
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 106e4500fd53..a44cd9cc12c4 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>
> @@ -41,6 +42,15 @@ 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.
its
> + * 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);
thanks.
--
~Randy
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