From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 29 Apr 2008 08:02:46 +0000 (+0200)
Subject: sched: fix hrtick_start_fair and CPU-Hotplug
X-Git-Tag: v2.6.26-rc2~62^2~9
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b328ca182f01c2a04b85e0ee8a410720b104fbcc;p=pandora-kernel.git

sched: fix hrtick_start_fair and CPU-Hotplug

Gautham R Shenoy reported:

 > While running the usual CPU-Hotplug stress tests on linux-2.6.25,
 > I noticed the following in the console logs.
 >
 > This is a wee bit difficult to reproduce. In the past 10 runs I hit this
 > only once.
 >
 > ------------[ cut here ]------------
 >
 > WARNING: at kernel/sched.c:962 hrtick+0x2e/0x65()
 >
 > Just wondering if we are doing a good job at handling the cancellation
 > of any per-cpu scheduler timers during CPU-Hotplug.

This looks like its indeed not cancelled at all and migrates the it to
another cpu. Fix it via a proper hotplug notifier mechanism.

Reported-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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