lkml.org 
[lkml]   [2012]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] watchdog: fix for lockup detector breakage on resume
On Mon, 07 May 2012 08:54:57 +0530
Anshuman Khandual <khandual@linux.vnet.ibm.com> wrote:

> On Tuesday 01 May 2012 10:52 PM, Sameer Nanda wrote:
>
> > On the suspend/resume path the boot CPU does not go though an
> > offline->online transition. This breaks the NMI detector
> > post-resume since it depends on PMU state that is lost when
> > the system gets suspended.
>
>
> We should not have allowed the PMU to go with events counting on it across the suspend/resume transition
> and find out that the state has been lost. This patch solves the problem of the NMI detector as we restart the
> counter again when the boot cpu comes back online during resume. But the original cause (PMU going with
> counters into the suspend state) which triggered this problem is still there. May be we should have called
> perf_event_exit() on the boot cpu before going into the suspend state.
>

That sounds like a nicer solution.

An implementation would be nice ;) I'll keep the original patch on life
support until we get all this nailed down.



\
 
 \ /
  Last update: 2012-06-09 00:21    [W:0.031 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site