[PATCH 2/5] workqueue: change value of lcpu in queue_delayed_work_on()

[Joonsoo Kim]

We assign cpu id into work struct in queue_delayed_work_on().
In current implementation, when work is come in first time,
current running cpu id is assigned.
If we do queue_delayed_work_on() with CPU A on CPU B,
__queue_work() invoked in delayed_work_timer_fn() go into sub-optimal path
in case of WQ_NON_REENTRANT.
Change it to cpu argument is prevent to go into sub-optimal path.

Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 188eef8..bc5c5e1 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1158,6 +1158,8 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 
 			if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND)
 				lcpu = gcwq->cpu;
+			else if (cpu >= 0)
+				lcpu = cpu;
 			else
 				lcpu = raw_smp_processor_id();
 		} else
-- 
1.7.9.5

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