lkml.org 
[lkml]   [2011]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/2 v2] watchdog: Always return NOTIFY_OK during cpu up/down events
From
Date
On Mon, 2011-03-07 at 16:37 -0500, Don Zickus wrote:
>
> This patch addresses a couple of problems. One was the case when the
> hardlockup failed to start, it also failed to start the softlockup.
> There were valid cases when the hardlockup shouldn't start and that
> shouldn't block the softlockup (no lapic, bios controls perf
> counters).
>
> The second problem was when the hardlockup failed to start on boxes
> (from a no lapic or bios controlled perf counter case), it reported
> failure to the cpu notifier chain. This blocked the notifier from
> continuing to start other more critical pieces of cpu bring-up (in
> our case based on a 2.6.32 fork, it was the mce). As a result,
> during soft cpu online/offline testing, the system would panic
> when a cpu was offlined because the cpu notifier would succeed in
> processing a watchdog disable cpu event and would panic in the mce
> case as a result of un-initialized variables from a never executed
> cpu up event.
>
> I realized the hardlockup/softlockup cases are really just debugging
> aids and should never impede the progress of a cpu up/down event.
> Therefore I modified the code to always return NOTIFY_OK and instead
> rely on printks to inform the user of problems.
>
> Signed-off-by: Don Zickus <dzickus@redhat.com>

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>


\
 
 \ /
  Last update: 2011-03-17 10:15    [W:0.330 / U:0.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site