diff options
| author | Kirill Tkhai <tkhai@yandex.ru> | 2013-01-30 13:50:36 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-01-31 10:31:13 +0100 |
| commit | fc79e240be5aa379dd36a62158be5a5ee0e4aec7 (patch) | |
| tree | 84e29ffa57509f586aff6a31ed0b0461f830fdaa /kernel/sched/rt.c | |
| parent | cputime: Avoid multiplication overflow on utime scaling (diff) | |
| download | linux-fc79e240be5aa379dd36a62158be5a5ee0e4aec7.tar.xz linux-fc79e240be5aa379dd36a62158be5a5ee0e4aec7.zip | |
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.c | 4 |
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)); |