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authorVincent Guittot <vincent.guittot@linaro.org>2018-04-26 12:19:32 +0200
committerIngo Molnar <mingo@kernel.org>2018-05-03 07:38:03 +0200
commit457be908c83637ee10bda085a23dc05afa3b14a0 (patch)
treee578083954eca7d085ad6428ca5ddc140657c40a
parent0b26351b910fb8fe6a056f8a1bbccabe50c0e19f (diff)
downloadlinux-457be908c83637ee10bda085a23dc05afa3b14a0.tar.bz2
sched/fair: Fix the update of blocked load when newly idle
With commit: 31e77c93e432 ("sched/fair: Update blocked load when newly idle") ... we release the rq->lock when updating blocked load of idle CPUs. This opens a time window during which another CPU can add a task to this CPU's cfs_rq. The check for newly added task of idle_balance() is not in the common path. Move the out label to include this check. Reported-by: Heiner Kallweit <hkallweit1@gmail.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 31e77c93e432 ("sched/fair: Update blocked load when newly idle") Link: http://lkml.kernel.org/r/20180426103133.GA6953@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/fair.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 54dc31e7ab9b..e3002e5ada31 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9847,6 +9847,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf)
if (curr_cost > this_rq->max_idle_balance_cost)
this_rq->max_idle_balance_cost = curr_cost;
+out:
/*
* While browsing the domains, we released the rq lock, a task could
* have been enqueued in the meantime. Since we're not going idle,
@@ -9855,7 +9856,6 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf)
if (this_rq->cfs.h_nr_running && !pulled_task)
pulled_task = 1;
-out:
/* Move the next balance forward */
if (time_after(this_rq->next_balance, next_balance))
this_rq->next_balance = next_balance;