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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>
This commit is contained in:
Mike Galbraith 2008-12-16 08:45:30 +01:00 committed by Ingo Molnar
parent d65bd5ecb2
commit 03e89e4574
2 changed files with 4 additions and 5 deletions
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2
kernel/sched.c
View File

@ -2266,6 +2266,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
smp_wmb();
rq = task_rq_lock(p, &flags);
update_rq_clock(rq);
old_state = p->state;
if (!(old_state & state))
goto out;
@ -2323,7 +2324,6 @@ out_activate:
schedstat_inc(p, se.nr_wakeups_local);
else
schedstat_inc(p, se.nr_wakeups_remote);
update_rq_clock(rq);
activate_task(rq, p, 1);
success = 1;

7
kernel/sched_fair.c
View File

@ -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);
update_curr(cfs_rq);
if (unlikely(rt_prio(p->prio))) {
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
update_rq_clock(rq);
update_curr(cfs_rq);
resched_task(curr);
return;
}