[PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Marco Crivellari]

Currently if a user enqueue 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.

system_wq should be the per-cpu workqueue, yet in this name nothing makes
that clear, so replace system_wq with system_percpu_wq.

The old wq (system_wq) will be kept for a few release cycles.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
---
 drivers/cxl/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index bd100ac31672..0be4e508affe 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -136,7 +136,7 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
 	if (opcode == CXL_MBOX_OP_SANITIZE) {
 		mutex_lock(&cxl_mbox->mbox_mutex);
 		if (mds->security.sanitize_node)
-			mod_delayed_work(system_wq, &mds->security.poll_dwork, 0);
+			mod_delayed_work(system_percpu_wq, &mds->security.poll_dwork, 0);
 		mutex_unlock(&cxl_mbox->mbox_mutex);
 	} else {
 		/* short-circuit the wait in __cxl_pci_mbox_send_cmd() */
-- 
2.51.0

Re: [PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Dave Jiang]

On 10/30/25 9:38 AM, Marco Crivellari wrote:
> Currently if a user enqueue 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.
> 
> system_wq should be the per-cpu workqueue, yet in this name nothing makes
> that clear, so replace system_wq with system_percpu_wq.
> 
> The old wq (system_wq) will be kept for a few release cycles.
> 
> Suggested-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>> ---
>  drivers/cxl/pci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index bd100ac31672..0be4e508affe 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -136,7 +136,7 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
>  	if (opcode == CXL_MBOX_OP_SANITIZE) {
>  		mutex_lock(&cxl_mbox->mbox_mutex);
>  		if (mds->security.sanitize_node)
> -			mod_delayed_work(system_wq, &mds->security.poll_dwork, 0);
> +			mod_delayed_work(system_percpu_wq, &mds->security.poll_dwork, 0);
>  		mutex_unlock(&cxl_mbox->mbox_mutex);
>  	} else {
>  		/* short-circuit the wait in __cxl_pci_mbox_send_cmd() */

Re: [PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Ira Weiny]

Marco Crivellari wrote:
> Currently if a user enqueue 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.
> 
> system_wq should be the per-cpu workqueue, yet in this name nothing makes
> that clear, so replace system_wq with system_percpu_wq.
> 
> The old wq (system_wq) will be kept for a few release cycles.

A reference to:

commit 128ea9f6ccfb6960293ae4212f4f97165e42222d
Author: Marco Crivellari <marco.crivellari@suse.com>
Date:   Sat Jun 14 15:35:29 2025 +0200

    workqueue: Add system_percpu_wq and system_dfl_wq

...

Would have been nice just to save reviewers time.  Regardless.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

[snip]

Re: [PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Davidlohr Bueso]

On Thu, 30 Oct 2025, Marco Crivellari wrote:

>Currently if a user enqueue 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.
>
>system_wq should be the per-cpu workqueue, yet in this name nothing makes
>that clear, so replace system_wq with system_percpu_wq.
>
>The old wq (system_wq) will be kept for a few release cycles.
>
>Suggested-by: Tejun Heo <tj@kernel.org>
>Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>

Acked-by: Davidlohr Bueso <dave@stgolabs.net>

Re: [PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Marco Crivellari]

On Fri, Oct 31, 2025 at 3:47 PM Ira Weiny <ira.weiny@intel.com> wrote:
>[...]
> A reference to:
>
> commit 128ea9f6ccfb6960293ae4212f4f97165e42222d
> Author: Marco Crivellari <marco.crivellari@suse.com>
> Date:   Sat Jun 14 15:35:29 2025 +0200
>
>     workqueue: Add system_percpu_wq and system_dfl_wq
>
> ...
>
> Would have been nice just to save reviewers time.  Regardless.
>
> Reviewed-by: Ira Weiny <ira.weiny@intel.com>

Many thanks, and sorry for the trouble!


--

Marco Crivellari

L3 Support Engineer, Technology & Product

Re: [PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Dave Jiang]

On 10/30/25 9:38 AM, Marco Crivellari wrote:
> Currently if a user enqueue 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.
> 
> system_wq should be the per-cpu workqueue, yet in this name nothing makes
> that clear, so replace system_wq with system_percpu_wq.
> 
> The old wq (system_wq) will be kept for a few release cycles.
> 
> Suggested-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>

Applied to cxl/next
952e9057e66c17a9718232664368ffdaca468f93

> ---
>  drivers/cxl/pci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index bd100ac31672..0be4e508affe 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -136,7 +136,7 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
>  	if (opcode == CXL_MBOX_OP_SANITIZE) {
>  		mutex_lock(&cxl_mbox->mbox_mutex);
>  		if (mds->security.sanitize_node)
> -			mod_delayed_work(system_wq, &mds->security.poll_dwork, 0);
> +			mod_delayed_work(system_percpu_wq, &mds->security.poll_dwork, 0);
>  		mutex_unlock(&cxl_mbox->mbox_mutex);
>  	} else {
>  		/* short-circuit the wait in __cxl_pci_mbox_send_cmd() */

Re: [PATCH] cxl/pci: replace use of system_wq with system_percpu_wq

[Marco Crivellari]

On Tue, Nov 4, 2025 at 12:44 AM Dave Jiang <dave.jiang@intel.com> wrote:
>[...]
> Applied to cxl/next
> 952e9057e66c17a9718232664368ffdaca468f93

Many thanks Dave!

-- 

Marco Crivellari

L3 Support Engineer, Technology & Product