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authorKirill Tkhai <tkhai@yandex.ru>2013-01-30 16:50:36 +0400
committerIngo Molnar <mingo@kernel.org>2013-01-31 10:31:13 +0100
commitfc79e240be5aa379dd36a62158be5a5ee0e4aec7 (patch)
tree84e29ffa57509f586aff6a31ed0b0461f830fdaa /kernel/sched/rt.c
parent62188451f0d63add7ad0cd2a1ae269d600c1663d (diff)
sched/rt: Do not account zero delta_exec in update_curr_rt()
There are several places of consecutive calls of dequeue_task_rt() and put_prev_task_rt() in the scheduler. For example, function rt_mutex_setprio() does it. The both calls lead to update_curr_rt(), the second of it receives zeroed delta_exec. The only effective action in this case is call of sched_rt_avg_update(), which can change rq->age_stamp and rq->rt_avg. But it is possible in case of ""floating"" rq->clock. This fact is not reasonable to be accounted. Another actions do nothing. Signed-off-by: Kirill V Tkhai <tkhai@yandex.ru> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> CC: linux-rt-users <linux-rt-users@vger.kernel.org> Link: http://lkml.kernel.org/r/931541359550236@web1g.yandex.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/rt.c')
-rw-r--r--kernel/sched/rt.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 2f69ca997826..94abca4d9cf5 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -925,8 +925,8 @@ static void update_curr_rt(struct rq *rq)
return;
delta_exec = rq->clock_task - curr->se.exec_start;
- if (unlikely((s64)delta_exec < 0))
- delta_exec = 0;
+ if (unlikely((s64)delta_exec <= 0))
+ return;
schedstat_set(curr->se.statistics.exec_max,
max(curr->se.statistics.exec_max, delta_exec));