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authorCyril Bur <cyrilbur@gmail.com>2015-02-12 15:01:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-12 18:54:13 -0800
commit545a2bf742fb41f17d03486dd8a8c74ad511dec2 (patch)
treef4e73814dd6f4df296e913f2089244759eb33108 /kernel/watchdog.c
parentdd4a5c1e6531b9c6ba6ee1f3cb11f0aeea25881e (diff)
downloadlinux-545a2bf742fb41f17d03486dd8a8c74ad511dec2.tar.bz2
kernel/sched/clock.c: add another clock for use with the soft lockup watchdog
When the hypervisor pauses a virtualised kernel the kernel will observe a jump in timebase, this can cause spurious messages from the softlockup detector. Whilst these messages are harmless, they are accompanied with a stack trace which causes undue concern and more problematically the stack trace in the guest has nothing to do with the observed problem and can only be misleading. Futhermore, on POWER8 this is completely avoidable with the introduction of the Virtual Time Base (VTB) register. This patch (of 2): This permits the use of arch specific clocks for which virtualised kernels can use their notion of 'running' time, not the elpased wall time which will include host execution time. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Jones <drjones@redhat.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: chai wen <chaiw.fnst@cn.fujitsu.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Ben Zhang <benzh@chromium.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/watchdog.c')
-rw-r--r--kernel/watchdog.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 70bf11815f84..3174bf8e3538 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -154,7 +154,7 @@ static int get_softlockup_thresh(void)
*/
static unsigned long get_timestamp(void)
{
- return local_clock() >> 30LL; /* 2^30 ~= 10^9 */
+ return running_clock() >> 30LL; /* 2^30 ~= 10^9 */
}
static void set_sample_period(void)