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authorWen Yang <wen.yang99@zte.com.cn>2018-02-05 11:18:41 +0800
committerIngo Molnar <mingo@kernel.org>2018-02-06 10:20:34 +0100
commite7ad203166fff89b1d8253faf68fbe6966bf7181 (patch)
tree80a3b9f71dfac9f1a4d1d0ed7399e663e7c1b403 /kernel
parent364f56653708ba8bcdefd4f0da2a42904baa8eeb (diff)
downloadlinux-e7ad203166fff89b1d8253faf68fbe6966bf7181.tar.bz2
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: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517800721-42092-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/rt.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 89a086ed2b16..663b2355a3aa 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;
if (curr->sched_class != &rt_sched_class)
return;
- delta_exec = rq_clock_task(rq) - curr->se.exec_start;
+ delta_exec = now - curr->se.exec_start;
if (unlikely((s64)delta_exec <= 0))
return;
@@ -968,7 +969,7 @@ static void update_curr_rt(struct rq *rq)
curr->se.sum_exec_runtime += delta_exec;
account_group_exec_runtime(curr, delta_exec);
- curr->se.exec_start = rq_clock_task(rq);
+ curr->se.exec_start = now;
cgroup_account_cputime(curr, delta_exec);
sched_rt_avg_update(rq, delta_exec);