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Commit a7558e01 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Add WF_FORK 



Avoid the cache buddies from biasing the time distribution away
from fork()ers. Normally the next buddy will be the preferred
scheduling target, but this makes fork()s prefer to run the new
child, whereas we prefer to run the parent, since that will
generate more work.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7d478721

include/linux/sched.h

+1 −0
Original line number Diff line number Diff line
@@ -1028,6 +1028,7 @@ struct sched_domain; 
 * wake flags

 */

#define WF_SYNC		0x01		/* waker goes to sleep after wakup */

#define WF_FORK		0x02		/* child wakeup after fork */



struct sched_class {

	const struct sched_class *next;

kernel/sched.c

+1 −1
Original line number Diff line number Diff line
@@ -2602,7 +2602,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) 
		inc_nr_running(rq);

	}

	trace_sched_wakeup_new(rq, p, 1);

	check_preempt_curr(rq, p, 0);

	check_preempt_curr(rq, p, WF_FORK);

#ifdef CONFIG_SMP

	if (p->sched_class->task_wake_up)

		p->sched_class->task_wake_up(rq, p);

kernel/sched_fair.c

+1 −1
Original line number Diff line number Diff line
@@ -1580,7 +1580,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int flags 
	 */

	if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))

		set_last_buddy(se);

	if (sched_feat(NEXT_BUDDY))

	if (sched_feat(NEXT_BUDDY) && !(flags & WF_FORK))

		set_next_buddy(pse);



	/*