[PATCH 1/2] workqueue: remove unneeded test before wake up next worker

From: Lai Jiangshan
Date: Wed Jul 16 2014 - 06:09:15 EST


In this code:
if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
wake_up_worker(pool);

the first test is unneeded. Even the first test is removed, it doesn't affect
the wake-up logic when WORKER_UNBOUND. And it will not introduce any useless
wake-up when !WORKER_UNBOUND since the nr_running >= 1 except only one case.
It will introduce useless/redundant wake-up when cpu_intensive, but this
case is rare and next patch will also remove this redundant wake-up.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
---
kernel/workqueue.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f8d54c1..6d11b9a 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2047,11 +2047,8 @@ __acquires(&pool->lock)
if (unlikely(cpu_intensive))
worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);

- /*
- * Unbound pool isn't concurrency managed and work items should be
- * executed ASAP. Wake up another worker if necessary.
- */
- if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
+ /* Wake up another worker if necessary. */
+ if (need_more_worker(pool))
wake_up_worker(pool);

/*
--
1.7.4.4

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