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sched, nohz: Change rq->nr_running to always use wrappers

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Sometimes ->nr_running may cross 2 but interrupt is not being
sent to rq's cpu. In this case we don't reenable the timer.
Looks like this may be the reason for rare unexpected effects,
if nohz is enabled.

Patch replaces all places of direct changing of nr_running
and makes add_nr_running() caring about crossing border.

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140508225830.2469.97461.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kirill Tkhai
2014-05-09 03:00:14 +04:00
committed by Ingo Molnar
parent 52a08ef1f1
commit 7246544786
5 changed files with 17 additions and 15 deletions
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4
kernel/sched/rt.c
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@@ -973,7 +973,7 @@ dequeue_top_rt_rq(struct rt_rq *rt_rq)
BUG_ON(!rq->nr_running);
rq->nr_running -= rt_rq->rt_nr_running;
sub_nr_running(rq, rt_rq->rt_nr_running);
rt_rq->rt_queued = 0;
}
@@ -989,7 +989,7 @@ enqueue_top_rt_rq(struct rt_rq *rt_rq)
if (rt_rq_throttled(rt_rq) || !rt_rq->rt_nr_running)
return;
rq->nr_running += rt_rq->rt_nr_running;
add_nr_running(rq, rt_rq->rt_nr_running);
rt_rq->rt_queued = 1;
}