Commit-ID: b932c03c34f3b03c7364c06aa8cae5b74609fc41 Gitweb: http://git.kernel.org/tip/b932c03c34f3b03c7364c06aa8cae5b74609fc41 Author: Rik van Riel <r...@redhat.com> AuthorDate: Mon, 4 Aug 2014 13:23:27 -0400 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 12 Aug 2014 12:48:22 +0200
sched/numa: Fix off-by-one in capacity check Commit a43455a1d572daf7b730fe12eb747d1e17411365 ensures that task_numa_migrate will call task_numa_compare on the preferred node all the time, even when the preferred node has no free capacity. This could lead to a performance regression if nr_running == capacity on both the source and the destination node. This can be avoided by also checking for nr_running == capacity on the source node, which is one stricter than checking .has_free_capacity. Signed-off-by: Rik van Riel <r...@redhat.com> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Cc: mgor...@suse.de Cc: vincent.guit...@linaro.org Cc: morten.rasmus...@arm.com Cc: nicolas.pi...@linaro.org Cc: efa...@gmx.de Cc: Linus Torvalds <torva...@linux-foundation.org> Link: http://lkml.kernel.org/r/1407173008-9334-2-git-send-email-r...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index df1ed17..e1cf419 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1206,7 +1206,7 @@ static void task_numa_compare(struct task_numa_env *env, if (!cur) { /* Is there capacity at our destination? */ - if (env->src_stats.has_free_capacity && + if (env->src_stats.nr_running <= env->src_stats.task_capacity && !env->dst_stats.has_free_capacity) goto unlock; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
