mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-29 23:53:32 +00:00
Code Issues Releases Wiki Activity

sched/numa: Avoid selecting oneself as swap target

Browse source 
Because the whole numa task selection stuff runs with preemption
enabled (its long and expensive) we can end up migrating and selecting
oneself as a swap target. This doesn't really work out well -- we end
up trying to acquire the same lock twice for the swap migrate -- so
avoid this.

Reported-and-Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20141110100328.GF29390@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2014-11-10 10:54:35 +01:00 committed by Ingo Molnar
parent c123588b3b
commit 7af683350c
1 changed files with 7 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
kernel/sched/fair.c
View file

@ -1179,6 +1179,13 @@ static void task_numa_compare(struct task_numa_env *env,
cur = NULL;
raw_spin_unlock_irq(&dst_rq->lock);
/*
* Because we have preemption enabled we can get migrated around and
* end try selecting ourselves (current == env->p) as a swap candidate.
*/
if (cur == env->p)
goto unlock;
/*
* "imp" is the fault differential for the source task between the
* source and destination node. Calculate the total differential for