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| author | Pavel Tatashin <pasha.tatashin@soleen.com> | 2021-05-07 03:04:41 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-05-07 09:26:32 +0200 |
| commit | b2075dbb15d7ae952aeb01331198f4dc45a7e46a (patch) | |
| tree | d6d75424ccf5e4c8129c35767418e08027b03cd6 | |
| parent | kernel: kexec_file: fix error return code of kexec_calculate_store_digests() (diff) | |
| download | linux-b2075dbb15d7ae952aeb01331198f4dc45a7e46a.tar.xz linux-b2075dbb15d7ae952aeb01331198f4dc45a7e46a.zip | |
kexec: dump kmessage before machine_kexec
kmsg_dump(KMSG_DUMP_SHUTDOWN) is called before machine_restart(),
machine_halt(), and machine_power_off(). The only one that is missing
is machine_kexec().
The dmesg output that it contains can be used to study the shutdown
performance of both kernel and systemd during kexec reboot.
Here is example of dmesg data collected after kexec:
root@dplat-cp22:~# cat /sys/fs/pstore/dmesg-ramoops-0 | tail
...
[ 70.914592] psci: CPU3 killed (polled 0 ms)
[ 70.915705] CPU4: shutdown
[ 70.916643] psci: CPU4 killed (polled 4 ms)
[ 70.917715] CPU5: shutdown
[ 70.918725] psci: CPU5 killed (polled 0 ms)
[ 70.919704] CPU6: shutdown
[ 70.920726] psci: CPU6 killed (polled 4 ms)
[ 70.921642] CPU7: shutdown
[ 70.922650] psci: CPU7 killed (polled 0 ms)
Link: https://lkml.kernel.org/r/20210319192326.146000-2-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/kexec_core.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index f04d04d1b855..f099baee3578 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -37,6 +37,7 @@ #include <linux/compiler.h> #include <linux/hugetlb.h> #include <linux/objtool.h> +#include <linux/kmsg_dump.h> #include <asm/page.h> #include <asm/sections.h> @@ -1179,6 +1180,7 @@ int kernel_kexec(void) machine_shutdown(); } + kmsg_dump(KMSG_DUMP_SHUTDOWN); machine_kexec(kexec_image); #ifdef CONFIG_KEXEC_JUMP |