Commit-ID: 77558e4d01ac0c7fa8cb1af4a61c2ab508d79f30
Gitweb: http://git.kernel.org/tip/77558e4d01ac0c7fa8cb1af4a61c2ab508d79f30
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 21 Feb 2017 14:36:23 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 16 Mar 2017 09:46:24 +0100
sched/core: Make sched_ttwu_pending() atomic in time
Since all tasks on the wake_list are woken under a single rq->lock
avoid calling update_rq_clock() for each task.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 247d0a0..dead90d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1685,7 +1685,7 @@ static void
ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
struct rq_flags *rf)
{
- int en_flags = ENQUEUE_WAKEUP;
+ int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;
lockdep_assert_held(&rq->lock);
@@ -1737,6 +1737,7 @@ void sched_ttwu_pending(void)
return;
rq_lock_irqsave(rq, &rf);
+ update_rq_clock(rq);
while (llist) {
int wake_flags = 0;
@@ -1849,6 +1850,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
#endif
rq_lock(rq, &rf);
+ update_rq_clock(rq);
ttwu_do_activate(rq, p, wake_flags, &rf);
rq_unlock(rq, &rf);
}
--
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