Commit-ID: d7d8294415f0ce4254827d4a2a5ee88b00be52a8 Gitweb: http://git.kernel.org/tip/d7d8294415f0ce4254827d4a2a5ee88b00be52a8 Author: Mike Galbraith <efault@xxxxxx> AuthorDate: Wed, 5 Jan 2011 05:41:17 +0100 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Tue, 18 Jan 2011 15:09:44 +0100 sched: Fix signed unsigned comparison in check_preempt_tick() Signed unsigned comparison may lead to superfluous resched if leftmost is right of the current task, wasting a few cycles, and inadvertently _lengthening_ the current task's slice. Reported-by: Venkatesh Pallipadi <venki@xxxxxxxxxx> Signed-off-by: Mike Galbraith <efault@xxxxxx> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> LKML-Reference: <1294202477.9384.5.camel@xxxxxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- kernel/sched_fair.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 414145c..77e9166 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1062,6 +1062,9 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) struct sched_entity *se = __pick_next_entity(cfs_rq); s64 delta = curr->vruntime - se->vruntime; + if (delta < 0) + return; + if (delta > ideal_runtime) resched_task(rq_of(cfs_rq)->curr); } -- 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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