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Groups > linux.kernel > #1393770

[PATCH] sched/fair: Update rq clock before updating nohz cpu load

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If we're accessing rq_clock() (e.g. in sched_avg_update()) we should
update the rq clock before calling cpu_load_update(), otherwise any
time calculations will be stale.

All other paths currently call update_rq_clock().

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
---
 kernel/sched/fair.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b8a33abce650..aa9ba82f0d7c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4723,6 +4723,7 @@ void cpu_load_update_nohz_stop(void)
 
 	load = weighted_cpuload(cpu_of(this_rq));
 	raw_spin_lock(&this_rq->lock);
+	update_rq_clock(this_rq);
 	cpu_load_update_nohz(this_rq, curr_jiffies, load);
 	raw_spin_unlock(&this_rq->lock);
 }
-- 
2.7.3

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[PATCH] sched/fair: Update rq clock before updating nohz cpu load Matt Fleming <matt@codeblueprint.co.uk> - 2016-05-03 21:50 +0200
  Re: [PATCH] sched/fair: Update rq clock before updating nohz cpu load Wanpeng Li <kernellwp@gmail.com> - 2016-05-04 03:10 +0200
  [tip:sched/core] sched/fair: Update rq clock before updating nohz  CPU load tip-bot for Matt Fleming <tipbot@zytor.com> - 2016-05-05 11:50 +0200

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