Commit-ID: ab2515c4b98f7bc4fa11cad9fa0f811d63a72a26
Gitweb: http://git.kernel.org/tip/ab2515c4b98f7bc4fa11cad9fa0f811d63a72a26
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Tue, 5 Apr 2011 17:23:52 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 14 Apr 2011 08:52:38 +0200
sched: Drop rq->lock from first part of wake_up_new_task()
Since p->pi_lock now protects all things needed to call
select_task_rq() avoid the double remote rq->lock acquisition and rely
on p->pi_lock.
Reviewed-by: Frank Rowand <frank.rowand@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20110405152729.273362517@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/sched.c | 17 +++--------------
1 files changed, 3 insertions(+), 14 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index f155127..7c5494d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2736,28 +2736,18 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
{
unsigned long flags;
struct rq *rq;
- int cpu __maybe_unused = get_cpu();
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
#ifdef CONFIG_SMP
- rq = task_rq_lock(p, &flags);
- p->state = TASK_WAKING;
-
/*
* Fork balancing, do it here and not earlier because:
* - cpus_allowed can change in the fork path
* - any previously selected cpu might disappear through hotplug
- *
- * We set TASK_WAKING so that select_task_rq() can drop rq->lock
- * without people poking at ->cpus_allowed.
*/
- cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
- set_task_cpu(p, cpu);
-
- p->state = TASK_RUNNING;
- task_rq_unlock(rq, p, &flags);
+ set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
#endif
- rq = task_rq_lock(p, &flags);
+ rq = __task_rq_lock(p);
activate_task(rq, p, 0);
p->on_rq = 1;
trace_sched_wakeup_new(p, true);
@@ -2767,7 +2757,6 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
p->sched_class->task_woken(rq, p);
#endif
task_rq_unlock(rq, p, &flags);
- put_cpu();
}
#ifdef CONFIG_PREEMPT_NOTIFIERS
--
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