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authorVincent Guittot <vincent.guittot@linaro.org>2012-09-13 06:11:26 +0200
committerViresh Kumar <viresh.kumar@linaro.org>2012-10-03 15:26:40 +0530
commit6e070a6118f052ebca2490eff68202897534f241 (patch)
tree2ec84eab1d1138371f6b40bba4765a7cf1abf9aa
parenta0d271cbfed1dd50278c6b06bead3d00ba0a88f9 (diff)
downloadvexpress-lsk-6e070a6118f052ebca2490eff68202897534f241.tar.gz
sched: Fix nohz_idle_balance()
On tickless systems, one CPU runs load balance for all idle CPUs. The cpu_load of this CPU is updated before starting the load balance of each other idle CPUs. We should instead update the cpu_load of the balance_cpu. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Venkatesh Pallipadi <venki@google.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Link: http://lkml.kernel.org/r/1347509486-8688-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/fair.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 96e2b18b628..dc09ec650e1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4837,14 +4837,15 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
if (need_resched())
break;
- raw_spin_lock_irq(&this_rq->lock);
- update_rq_clock(this_rq);
- update_idle_cpu_load(this_rq);
- raw_spin_unlock_irq(&this_rq->lock);
+ rq = cpu_rq(balance_cpu);
+
+ raw_spin_lock_irq(&rq->lock);
+ update_rq_clock(rq);
+ update_idle_cpu_load(rq);
+ raw_spin_unlock_irq(&rq->lock);
rebalance_domains(balance_cpu, CPU_IDLE);
- rq = cpu_rq(balance_cpu);
if (time_after(this_rq->next_balance, rq->next_balance))
this_rq->next_balance = rq->next_balance;
}