* [PATCH] workqueue: Create kworker only for boot CPU pool prior SMP initialization
@ 2022-03-31 13:14 Zqiang
2022-04-04 17:40 ` Tejun Heo
0 siblings, 1 reply; 2+ messages in thread
From: Zqiang @ 2022-03-31 13:14 UTC (permalink / raw)
To: tj, jiangshanlai; +Cc: linux-kernel
The workqueue_init() is called before SMP initialization, which
means only the boot CPU is online, just create kworker for boot
CPU pool.
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
---
kernel/workqueue.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index abcc9a2ac319..3948babe02d5 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -6120,11 +6120,9 @@ void __init workqueue_init(void)
mutex_unlock(&wq_pool_mutex);
/* create the initial workers */
- for_each_online_cpu(cpu) {
- for_each_cpu_worker_pool(pool, cpu) {
- pool->flags &= ~POOL_DISASSOCIATED;
- BUG_ON(!create_worker(pool));
- }
+ for_each_cpu_worker_pool(pool, smp_processor_id()) {
+ pool->flags &= ~POOL_DISASSOCIATED;
+ BUG_ON(!create_worker(pool));
}
hash_for_each(unbound_pool_hash, bkt, pool, hash_node)
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] workqueue: Create kworker only for boot CPU pool prior SMP initialization
2022-03-31 13:14 [PATCH] workqueue: Create kworker only for boot CPU pool prior SMP initialization Zqiang
@ 2022-04-04 17:40 ` Tejun Heo
0 siblings, 0 replies; 2+ messages in thread
From: Tejun Heo @ 2022-04-04 17:40 UTC (permalink / raw)
To: Zqiang; +Cc: jiangshanlai, linux-kernel
On Thu, Mar 31, 2022 at 09:14:35PM +0800, Zqiang wrote:
> The workqueue_init() is called before SMP initialization, which
> means only the boot CPU is online, just create kworker for boot
> CPU pool.
>
> Signed-off-by: Zqiang <qiang1.zhang@intel.com>
> ---
> kernel/workqueue.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index abcc9a2ac319..3948babe02d5 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -6120,11 +6120,9 @@ void __init workqueue_init(void)
> mutex_unlock(&wq_pool_mutex);
>
> /* create the initial workers */
> - for_each_online_cpu(cpu) {
> - for_each_cpu_worker_pool(pool, cpu) {
> - pool->flags &= ~POOL_DISASSOCIATED;
> - BUG_ON(!create_worker(pool));
> - }
> + for_each_cpu_worker_pool(pool, smp_processor_id()) {
> + pool->flags &= ~POOL_DISASSOCIATED;
> + BUG_ON(!create_worker(pool));
I mean, I guess this would work but what's the benefit? It doesn't make any
practical difference and the code is now more fragile to external changes.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-03-31 13:14 [PATCH] workqueue: Create kworker only for boot CPU pool prior SMP initialization Zqiang
2022-04-04 17:40 ` Tejun Heo
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