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 <[email protected]> CC: Steven Rostedt <[email protected]> CC: Ingo Molnar <[email protected]> CC: Peter Zijlstra <[email protected]> CC: linux-rt-users <[email protected]> --- 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 4e8f0f4..c6d7993 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)); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
