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author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2012-09-18 16:59:23 (GMT) |
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committer | Tejun Heo <tj@kernel.org> | 2012-09-18 16:59:23 (GMT) |
commit | a5b4e57d7cc07cb28ccf16de0876a4770ae84920 (patch) | |
tree | b73c1549f50a5acc98783e3a29a6612ae4de28ba /kernel/workqueue.c | |
parent | 9fdf9b73d61c87a9c16f101bb8bbe069d13046f5 (diff) | |
download | linux-fsl-qoriq-a5b4e57d7cc07cb28ccf16de0876a4770ae84920.tar.xz |
workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback()
workqueue_cpu_down_callback() is used only if HOTPLUG_CPU=y, so
hotcpu_notifier() fits better than cpu_notifier().
When HOTPLUG_CPU=y, hotcpu_notifier() and cpu_notifier() are the same.
When HOTPLUG_CPU=n, if we use cpu_notifier(),
workqueue_cpu_down_callback() will be called during boot to do
nothing, and the memory of workqueue_cpu_down_callback() and
gcwq_unbind_fn() will be discarded after boot.
If we use hotcpu_notifier(), we can avoid the no-op call of
workqueue_cpu_down_callback() and the memory of
workqueue_cpu_down_callback() and gcwq_unbind_fn() will be discard at
build time:
$ ls -l kernel/workqueue.o.cpu_notifier kernel/workqueue.o.hotcpu_notifier
-rw-rw-r-- 1 laijs laijs 484080 Sep 15 11:31 kernel/workqueue.o.cpu_notifier
-rw-rw-r-- 1 laijs laijs 478240 Sep 15 11:31 kernel/workqueue.o.hotcpu_notifier
$ size kernel/workqueue.o.cpu_notifier kernel/workqueue.o.hotcpu_notifier
text data bss dec hex filename
18513 2387 1221 22121 5669 kernel/workqueue.o.cpu_notifier
18082 2355 1221 21658 549a kernel/workqueue.o.hotcpu_notifier
tj: Updated description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r-- | kernel/workqueue.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 942bb75..48becab 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3807,7 +3807,7 @@ static int __init init_workqueues(void) WORK_CPU_LAST); cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); - cpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); + hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); /* initialize gcwqs */ for_each_gcwq_cpu(cpu) { |