diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-14 20:02:34 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-15 16:51:31 +0200 |
| commit | a7558e01056f5191ff2ecff53b075dcb9e484188 (patch) | |
| tree | 1364bbf9273ce353f4f3146aebe567f79b7c8cad | |
| parent | 7d47872146398dbede13223299fe1cb368ebc781 (diff) | |
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: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/sched.c | 2 | ||||
| -rw-r--r-- | kernel/sched_fair.c | 2 |
3 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 3b07168b6f0..ee1f8899309 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -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; diff --git a/kernel/sched.c b/kernel/sched.c index 4da335cec8e..0d4c4fea331 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 007958e3c93..6766959c7f4 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -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); /* |