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authorWen Yang <wen.yang99@zte.com.cn>2018-02-06 09:53:28 +0800
committerIngo Molnar <mingo@kernel.org>2018-02-13 11:44:41 +0100
commita7711602c7b79950ea437178f601b52ab08ef659 (patch)
treeaaa36c553654b2cd4499c8f3be505e173d03ff16 /kernel/sched
parent6fe0ce1eb04f99a1eb1eb6e7f775666966cf6c80 (diff)
sched/rt: Make update_curr_rt() more accurate
rq->clock_task may be updated between the two calls of rq_clock_task() in update_curr_rt(). Calling rq_clock_task() only once makes it more accurate and efficient, taking update_curr() as reference. Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517882008-44552-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/rt.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 663b2355a3aa..aad49451584e 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -950,12 +950,13 @@ static void update_curr_rt(struct rq *rq)
{
struct task_struct *curr = rq->curr;
struct sched_rt_entity *rt_se = &curr->rt;
- u64 now = rq_clock_task(rq);
u64 delta_exec;
+ u64 now;
if (curr->sched_class != &rt_sched_class)
return;
+ now = rq_clock_task(rq);
delta_exec = now - curr->se.exec_start;
if (unlikely((s64)delta_exec <= 0))
return;