This is a note to let you know that I've just added the patch titled
sched: Fix load avg vs. cpu-hotplug
to the 3.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-fix-load-avg-vs.-cpu-hotplug.patch
and it can be found in the queue-3.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 08bedae1d0acd8c9baf514fb69fa199d0c8345f6 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <[email protected]>
Date: Thu, 6 Sep 2012 00:03:50 +0200
Subject: sched: Fix load avg vs. cpu-hotplug
From: Peter Zijlstra <[email protected]>
commit 08bedae1d0acd8c9baf514fb69fa199d0c8345f6 upstream.
Commit f319da0c68 ("sched: Fix load avg vs cpu-hotplug") was an
incomplete fix:
In particular, the problem is that at the point it calls
calc_load_migrate() nr_running := 1 (the stopper thread), so move the
call to CPU_DEAD where we're sure that nr_running := 0.
Also note that we can call calc_load_migrate() without serialization, we
know the state of rq is stable since its cpu is dead, and we modify the
global state using appropriate atomic ops.
Suggested-by: Paul E. McKenney <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/1346882630.2600.59.camel@twins
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/sched/core.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5604,7 +5604,9 @@ migration_call(struct notifier_block *nf
migrate_tasks(cpu);
BUG_ON(rq->nr_running != 1); /* the migration thread */
raw_spin_unlock_irqrestore(&rq->lock, flags);
+ break;
+ case CPU_DEAD:
calc_load_migrate(rq);
break;
#endif
Patches currently in stable-queue which might be from [email protected] are
queue-3.6/slab-fix-the-deadlock-issue-on-l3-alien-lock.patch
queue-3.6/sched-fix-load-avg-vs.-cpu-hotplug.patch
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