[v2] RAS/CEC: replace use of system_wq with system_percpu_wq

[PATCH v2] RAS/CEC: replace use of system_wq with system_percpu_wq

Posted by Marco Crivellari 1 month, 1 week ago

Currently if a user enqueues a work item using schedule_delayed_work() the
used workqueue is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a CPU is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistency cannot be addressed without refactoring the API.
For more details see the Link tag below.

This continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

Switch to using system_percpu_wq because system_wq is going away as part of
a workqueue restructuring.

Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
---
 drivers/ras/cec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index e440b15fbabc..15f7f043c8ef 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -166,7 +166,7 @@ static void cec_mod_work(unsigned long interval)
 	unsigned long iv;
 
 	iv = interval * HZ;
-	mod_delayed_work(system_wq, &cec_work, round_jiffies(iv));
+	mod_delayed_work(system_percpu_wq, &cec_work, round_jiffies(iv));
 }
 
 static void cec_work_fn(struct work_struct *work)
-- 
2.51.1

Re: [PATCH v2] RAS/CEC: replace use of system_wq with system_percpu_wq

Posted by Borislav Petkov 1 month, 1 week ago

On Thu, Nov 06, 2025 at 12:24:54PM +0100, Marco Crivellari wrote:
> Currently if a user enqueues a work item using schedule_delayed_work() the
> used workqueue is "system_wq" (per-cpu wq) while queue_delayed_work() use
> WORK_CPU_UNBOUND (used when a CPU is not specified). The same applies to
> schedule_work() that is using system_wq and queue_work(), that makes use
> again of WORK_CPU_UNBOUND.
> 
> This lack of consistency cannot be addressed without refactoring the API.
> For more details see the Link tag below.
> 
> This continues the effort to refactor workqueue APIs, which began with
> the introduction of new workqueues and a new alloc_workqueue flag in:
> 
> commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
> commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")
> 
> Switch to using system_percpu_wq because system_wq is going away as part of
> a workqueue restructuring.
> 
> Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de
> Suggested-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
> ---
>  drivers/ras/cec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v2] RAS/CEC: replace use of system_wq with system_percpu_wq

Posted by Marco Crivellari 1 month, 1 week ago

On Fri, Nov 7, 2025 at 2:00 PM Borislav Petkov <bp@alien8.de> wrote:
>[...]
> Applied, thanks.

Many thanks!

-- 

Marco Crivellari

L3 Support Engineer, Technology & Product