sched: Complete buddy switches

Add a NEXT_BUDDY feature flag to aid in debugging.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index cea5b82242ee54dcdae91c396033cbaef306eed7..4f6356e70ad65abdfabff76970fcefa84be38938 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1501,7 +1501,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
         */
        if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
                set_last_buddy(se);
-       set_next_buddy(pse);
+       if (sched_feat(NEXT_BUDDY))
+               set_next_buddy(pse);
 
        /*
         * We can come here with TIF_NEED_RESCHED already set from new task

diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 07c8250b404c7e3475cec1578649eda9cee8b94e..6174c1233993cba9d1e87336e7ed38569384f0bb 100644 (file)
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -14,5 +14,6 @@ SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
 SCHED_FEAT(ASYM_EFF_LOAD, 1)
 SCHED_FEAT(WAKEUP_SYNC, 0)
 SCHED_FEAT(WAKEUP_OVERLAP, 0)
+SCHED_FEAT(NEXT_BUDDY, 1)
 SCHED_FEAT(LAST_BUDDY, 1)
 SCHED_FEAT(OWNER_SPIN, 1)