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authorPavel Tatashin2021-05-06 18:04:41 -0700
committerLinus Torvalds2021-05-07 00:26:32 -0700
commitb2075dbb15d7ae952aeb01331198f4dc45a7e46a (patch)
treed6d75424ccf5e4c8129c35767418e08027b03cd6
parent31d82c2c787d5cf65fedd35ebbc0c1bd95c1a679 (diff)
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.c2
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