Commit-ID: 7af683350cb0ddd0e9d3819b4eb7abe9e2d3e709 Gitweb: http://git.kernel.org/tip/7af683350cb0ddd0e9d3819b4eb7abe9e2d3e709 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Mon, 10 Nov 2014 10:54:35 +0100 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Sun, 16 Nov 2014 10:04:17 +0100 sched/numa: Avoid selecting oneself as swap target 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@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20141110100328.GF29390@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- kernel/sched/fair.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 34baa60..3af3d1e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1180,6 +1180,13 @@ static void task_numa_compare(struct task_numa_env *env, 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 * the source task and potential destination task. The more negative -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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