From 6d1cafd8b56ea726c10a5a104de57cc3ed8fa953 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Tue, 1 Mar 2011 16:28:21 -0800 Subject: [PATCH] sched: Resched proper CPU on yield_to() yield_to_task_fair() has code to resched the CPU of yielding task when the intention is to resched the CPU of the task that is being yielded to. Change here fixes the problem and also makes the resched conditional on rq != p_rq. Signed-off-by: Venkatesh Pallipadi Reviewed-by: Rik van Riel Signed-off-by: Peter Zijlstra LKML-Reference: <1299025701-22168-1-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 9 ++++++++- kernel/sched_fair.c | 4 ---- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index f3030709d826..61452e86c73b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5522,8 +5522,15 @@ bool __sched yield_to(struct task_struct *p, bool preempt) goto out; yielded = curr->sched_class->yield_to_task(rq, p, preempt); - if (yielded) + if (yielded) { schedstat_inc(rq, yld_count); + /* + * Make p's CPU reschedule; pick_next_entity takes care of + * fairness. + */ + if (preempt && rq != p_rq) + resched_task(p_rq->curr); + } out: double_rq_unlock(rq, p_rq); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 1438e13cf8be..3f7ec9e27ee1 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1987,10 +1987,6 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp /* Tell the scheduler that we'd really like pse to run next. */ set_next_buddy(se); - /* Make p's CPU reschedule; pick_next_entity takes care of fairness. */ - if (preempt) - resched_task(rq->curr); - yield_task_fair(rq); return true;