Commit-ID: 457be908c83637ee10bda085a23dc05afa3b14a0
Gitweb: https://git.kernel.org/tip/457be908c83637ee10bda085a23dc05afa3b14a0
Author: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
AuthorDate: Thu, 26 Apr 2018 12:19:32 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 3 May 2018 07:38:03 +0200
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@xxxxxxxxx>
Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: 31e77c93e432 ("sched/fair: Update blocked load when newly idle")
Link: http://lkml.kernel.org/r/20180426103133.GA6953@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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;
--
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