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From: Cyril Bur <cyrilbur@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: mpe@ellerman.id.au, drjones@redhat.com, dzickus@redhat.com,
	akpm@linux-foundation.org, mingo@kernel.org, uobergfe@redhat.com,
	chaiw.fnst@cn.fujitsu.com, cl@linu.com, fabf@skynet.be,
	atomlin@redhat.com, benzh@chromium.org,
	Cyril Bur <cyrilbur@gmail.com>
Subject: [PATCH 0/2] Quieten softlockup detector on virtualised kernels
Date: Mon, 22 Dec 2014 16:06:02 +1100	[thread overview]
Message-ID: <1419224764-11384-1-git-send-email-cyrilbur@gmail.com> (raw)

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.

Cyril Bur (2):
  Add another clock for use with the soft lockup watchdog.
  powerpc: add running_clock for powerpc to prevent spurious softlockup
    warnings

 arch/powerpc/kernel/time.c | 24 ++++++++++++++++++++++++
 include/linux/sched.h      |  1 +
 kernel/sched/clock.c       | 14 ++++++++++++++
 kernel/watchdog.c          |  2 +-
 4 files changed, 40 insertions(+), 1 deletion(-)

-- 
1.9.1


             reply	other threads:[~2014-12-22  5:06 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-22  5:06 Cyril Bur [this message]
2014-12-22  5:06 ` [PATCH 1/2] Add another clock for use with the soft lockup watchdog Cyril Bur
2015-01-05 22:09   ` Andrew Morton
2014-12-22  5:06 ` [PATCH 2/2] powerpc: add running_clock for powerpc to prevent spurious softlockup warnings Cyril Bur
2015-01-05 22:10   ` Andrew Morton
2015-01-06  2:44     ` Cyril Bur
2015-01-07 10:20       ` Martin Schwidefsky
2015-01-09  3:22         ` Cyril Bur
2015-01-05 16:50 ` [PATCH 0/2] Quieten softlockup detector on virtualised kernels Don Zickus
2015-01-05 23:53   ` Cyril Bur
2015-01-06 15:01     ` Don Zickus
2015-01-09  3:15       ` Cyril Bur
2015-01-09 14:56         ` Don Zickus
2015-01-05 22:09 ` Andrew Morton
2015-01-06  2:43   ` Cyril Bur
  -- strict thread matches above, loose matches on Subject: below --
2014-12-01  2:38 Cyril Bur

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