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@google.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294202477.9384.5.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -1062,6 +1062,9 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
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struct sched_entity *se = __pick_next_entity(cfs_rq);
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struct sched_entity *se = __pick_next_entity(cfs_rq);
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s64 delta = curr->vruntime - se->vruntime;
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s64 delta = curr->vruntime - se->vruntime;
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if (delta < 0)
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return;
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if (delta > ideal_runtime)
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if (delta > ideal_runtime)
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resched_task(rq_of(cfs_rq)->curr);
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resched_task(rq_of(cfs_rq)->curr);
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}
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}
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