Currently if a user enqueues a work item using schedule_delayed_work() the
used wq 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.

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.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
---
Changes in v2:
- improved commit log
- rebased on 6.18-rc5
---
 kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 02f52291fae4..496358eae37c 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -1137,7 +1137,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
 	if (cpu >= nr_cpu_ids || !cpu_online(cpu))
 		return -ENXIO;
 
-	queue_work_on(cpu, system_wq, &sscs.work);
+	queue_work_on(cpu, system_percpu_wq, &sscs.work);
 	wait_for_completion(&sscs.done);
 	destroy_work_on_stack(&sscs.work);
 
-- 
2.51.1

Le Mon, Nov 10, 2025 at 06:03:32PM +0100, Marco Crivellari a écrit :
> Currently if a user enqueues a work item using schedule_delayed_work() the
> used wq 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.
> 
> 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.
> 
> Suggested-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
> ---
> Changes in v2:
> - improved commit log
> - rebased on 6.18-rc5
> ---
>  kernel/smp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index 02f52291fae4..496358eae37c 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -1137,7 +1137,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
>  	if (cpu >= nr_cpu_ids || !cpu_online(cpu))
>  		return -ENXIO;
>  
> -	queue_work_on(cpu, system_wq, &sscs.work);
> +	queue_work_on(cpu, system_percpu_wq, &sscs.work);

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

-- 
Frederic Weisbecker
SUSE Labs

On Mon, Nov 10, 2025 at 6:03 PM Marco Crivellari
<marco.crivellari@suse.com> wrote:
> [...]
>  kernel/smp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/smp.c b/kernel/smp.c
> index 02f52291fae4..496358eae37c 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -1137,7 +1137,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
>         if (cpu >= nr_cpu_ids || !cpu_online(cpu))
>                 return -ENXIO;
>
> -       queue_work_on(cpu, system_wq, &sscs.work);
> +       queue_work_on(cpu, system_percpu_wq, &sscs.work);
>         wait_for_completion(&sscs.done);
>         destroy_work_on_stack(&sscs.work);
>

Gentle ping.

Thanks!

-- 

Marco Crivellari

L3 Support Engineer

On Wed, Dec 24, 2025 at 4:19 PM Marco Crivellari
<marco.crivellari@suse.com> wrote:
> [...]
> >  kernel/smp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>

Gentle ping.

Thanks!

-- 

Marco Crivellari

L3 Support Engineer