Messages in this thread | | | Date | Thu, 5 Feb 2015 15:48:49 -0500 | From | Don Zickus <> | Subject | Re: [PATCH v2 0/2] Quieten softlockup detector on virtualised kernels |
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On Fri, Jan 09, 2015 at 02:34:36PM +1100, Cyril Bur wrote: > 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.
Originally I was suggesting to talk with the x86/kvm folks about coming up with a common solution. But I didn't hear a response from those cc'd at the time. This solution looks a lot cleaner than what x86 is doing.
I am willing to see how this works out on ppc64's kvm and see if they still see any issues after awhile. If not, maybe I can poke the x86 folks to migrate to something similar.
Acked-by: Don Zickus <dzickus@redhat.com>
> > Futhermore, on POWER8 this is completely avoidable with the introduction of > the Virtual Time Base (VTB) register. > > V2: > Remove the export of running_clock > Added #ifdef CONFIG_PPC_PSERIES and optimised the non lpar + vtb cases. > Replaced the use of sched_clock_with local_clock it was used originally in > the softlockup detector. > > 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 | 32 ++++++++++++++++++++++++++++++++ > include/linux/sched.h | 1 + > kernel/sched/clock.c | 13 +++++++++++++ > kernel/watchdog.c | 2 +- > 4 files changed, 47 insertions(+), 1 deletion(-) > > -- > 1.9.1 >
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