On Tue, Apr 15, 2014 at 09:32:53PM +0900, Dongsheng Yang wrote: > From: Dongsheng <[email protected]> > > It is pointless to wake up a running task. Currently, we can > see it in perf sched latency. > > Signed-off-by: Dongsheng <[email protected]> > --- > kernel/sched/core.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 268a45e..fc6b644 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -1416,6 +1416,9 @@ static void ttwu_activate(struct rq *rq, struct > task_struct *p, int en_flags) > static void > ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) > { > + if (p->state == TASK_RUNNING) > + return; > + > check_preempt_curr(rq, p, wake_flags); > trace_sched_wakeup(p, true); >
How can you get there with ->state == RUNNING? try_to_wake_up*() bail when !(->state & state). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
