The patch titled
Subject: kexec: dump kmessage before machine_kexec
has been added to the -mm tree. Its filename is
kexec-dump-kmessage-before-machine_kexec.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kexec-dump-kmessage-before-machine_kexec.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kexec-dump-kmessage-before-machine_kexec.patch
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------------------------------------------------------
From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Subject: kexec: dump kmessage before machine_kexec
kmsg_dump(KMSG_DUMP_SHUTDOWN) is called before
machine_restart(), machine_halt(), 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
...
<6>[ 70.914592] psci: CPU3 killed (polled 0 ms)
<5>[ 70.915705] CPU4: shutdown
<6>[ 70.916643] psci: CPU4 killed (polled 4 ms)
<5>[ 70.917715] CPU5: shutdown
<6>[ 70.918725] psci: CPU5 killed (polled 0 ms)
<5>[ 70.919704] CPU6: shutdown
<6>[ 70.920726] psci: CPU6 killed (polled 4 ms)
<5>[ 70.921642] CPU7: shutdown
<6>[ 70.922650] psci: CPU7 killed (polled 0 ms)
Link: https://lkml.kernel.org/r/20210319192326.146000-2-pasha.tatashin@xxxxxxxxxx
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Reviewed-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Sasha Levin <sashal@xxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Anton Vorontsov <anton@xxxxxxxxxx>
Cc: Colin Cross <ccross@xxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kexec_core.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/kexec_core.c~kexec-dump-kmessage-before-machine_kexec
+++ a/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
_
Patches currently in -mm which might be from pasha.tatashin@xxxxxxxxxx are
mm-gup-dont-pin-migrated-cma-pages-in-movable-zone.patch
mm-gup-check-every-subpage-of-a-compound-page-during-isolation.patch
mm-gup-return-an-error-on-migration-failure.patch
mm-gup-check-for-isolation-errors.patch
mm-cma-rename-pf_memalloc_nocma-to-pf_memalloc_pin.patch
mm-apply-per-task-gfp-constraints-in-fast-path.patch
mm-honor-pf_memalloc_pin-for-all-movable-pages.patch
mm-gup-do-not-migrate-zero-page.patch
mm-gup-migrate-pinned-pages-out-of-movable-zone.patch
memory-hotplugrst-add-a-note-about-zone_movable-and-page-pinning.patch
mm-gup-change-index-type-to-long-as-it-counts-pages.patch
mm-gup-longterm-pin-migration-cleanup.patch
selftests-vm-gup_test-fix-test-flag.patch
selftests-vm-gup_test-test-faulting-in-kernel-and-verify-pinnable-pages.patch
kexec-dump-kmessage-before-machine_kexec.patch
