sched: fix wakeup preemption clock

Impact: sharpen the wakeup-granularity to always be against current scheduler time

It was possible to do the preemption check against an old time stamp.

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

1 files changed, 3 insertions, 4 deletions

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 98345e45b059..928cd74cff0d 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1345,12 +1345,11 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
 {
         struct task_struct *curr = rq->curr;
         struct sched_entity *se = &curr->se, *pse = &p->se;
+        struct cfs_rq *cfs_rq = task_cfs_rq(curr);
 
-        if (unlikely(rt_prio(p->prio))) {
-                struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+        update_curr(cfs_rq);
 
-                update_rq_clock(rq);
-                update_curr(cfs_rq);
+        if (unlikely(rt_prio(p->prio))) {
                 resched_task(curr);
                 return;
         }