[PATCH 0/2] replace system_unbound_wq and system_wq with the new wqs

[PATCH 0/2] replace system_unbound_wq and system_wq with the new wqs

[Marco Crivellari]

Hi,

=== Current situation: problems ===

Let's consider a nohz_full system with isolated CPUs: wq_unbound_cpumask is
set to the housekeeping CPUs, for !WQ_UNBOUND the local CPU is selected.

This leads to different scenarios if a work item is scheduled on an isolated
CPU where "delay" value is 0 or greater then 0:
        schedule_delayed_work(, 0);

This will be handled by __queue_work() that will queue the work item on the
current local (isolated) CPU, while:

        schedule_delayed_work(, 1);

Will move the timer on an housekeeping CPU, and schedule the work there.

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 consistentcy cannot be addressed without refactoring the API.

=== Recent changes to the WQ API ===

The following, address the recent changes in the Workqueue API:

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

The old workqueues will be removed in a future release cycle.

=== Introduced Changes by this series ===

1) [P 1-2] Replace uses of system_wq and system_unbound_wq

    system_wq is a per-CPU workqueue, but his name is not clear.
    system_unbound_wq is to be used when locality is not required.

    Because of that, system_wq has been replaced with system_percpu_wq, and
    system_unbound_wq has been replaced with system_dfl_wq.


Thanks!


Marco Crivellari (2):
  accel/ivpu: replace use of system_unbound_wq with system_dfl_wq
  accel/ivpu: replace use of system_wq with system_percpu_wq

 drivers/accel/ivpu/ivpu_hw_btrs.c | 2 +-
 drivers/accel/ivpu/ivpu_ipc.c     | 2 +-
 drivers/accel/ivpu/ivpu_job.c     | 2 +-
 drivers/accel/ivpu/ivpu_mmu.c     | 2 +-
 drivers/accel/ivpu/ivpu_pm.c      | 4 ++--
 5 files changed, 6 insertions(+), 6 deletions(-)

-- 
2.51.0

[PATCH 1/2] accel/ivpu: replace use of system_unbound_wq with system_dfl_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 consistentcy cannot be addressed without refactoring the API.

system_unbound_wq should be the default workqueue so as not to enforce
locality constraints for random work whenever it's not required.

Adding system_dfl_wq to encourage its use when unbound work should be used.

The old system_unbound_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/accel/ivpu/ivpu_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
index 475ddc94f1cf..ffa2ba7cafe2 100644
--- a/drivers/accel/ivpu/ivpu_pm.c
+++ b/drivers/accel/ivpu/ivpu_pm.c
@@ -186,7 +186,7 @@ void ivpu_pm_trigger_recovery(struct ivpu_device *vdev, const char *reason)
 	if (atomic_cmpxchg(&vdev->pm->reset_pending, 0, 1) == 0) {
 		ivpu_hw_diagnose_failure(vdev);
 		ivpu_hw_irq_disable(vdev); /* Disable IRQ early to protect from IRQ storm */
-		queue_work(system_unbound_wq, &vdev->pm->recovery_work);
+		queue_work(system_dfl_wq, &vdev->pm->recovery_work);
 	}
 }
 
-- 
2.51.0

[PATCH 2/2] accel/ivpu: 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 consistentcy 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/accel/ivpu/ivpu_hw_btrs.c | 2 +-
 drivers/accel/ivpu/ivpu_ipc.c     | 2 +-
 drivers/accel/ivpu/ivpu_job.c     | 2 +-
 drivers/accel/ivpu/ivpu_mmu.c     | 2 +-
 drivers/accel/ivpu/ivpu_pm.c      | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/accel/ivpu/ivpu_hw_btrs.c b/drivers/accel/ivpu/ivpu_hw_btrs.c
index afdb3b2aa72a..27a345f3befe 100644
--- a/drivers/accel/ivpu/ivpu_hw_btrs.c
+++ b/drivers/accel/ivpu/ivpu_hw_btrs.c
@@ -673,7 +673,7 @@ bool ivpu_hw_btrs_irq_handler_lnl(struct ivpu_device *vdev, int irq)
 
 	if (REG_TEST_FLD(VPU_HW_BTRS_LNL_INTERRUPT_STAT, SURV_ERR, status)) {
 		ivpu_dbg(vdev, IRQ, "Survivability IRQ\n");
-		queue_work(system_wq, &vdev->irq_dct_work);
+		queue_work(system_percpu_wq, &vdev->irq_dct_work);
 	}
 
 	if (REG_TEST_FLD(VPU_HW_BTRS_LNL_INTERRUPT_STAT, FREQ_CHANGE, status)) {
diff --git a/drivers/accel/ivpu/ivpu_ipc.c b/drivers/accel/ivpu/ivpu_ipc.c
index 5f00809d448a..1f13bf95b2b3 100644
--- a/drivers/accel/ivpu/ivpu_ipc.c
+++ b/drivers/accel/ivpu/ivpu_ipc.c
@@ -459,7 +459,7 @@ void ivpu_ipc_irq_handler(struct ivpu_device *vdev)
 		}
 	}
 
-	queue_work(system_wq, &vdev->irq_ipc_work);
+	queue_work(system_percpu_wq, &vdev->irq_ipc_work);
 }
 
 void ivpu_ipc_irq_work_fn(struct work_struct *work)
diff --git a/drivers/accel/ivpu/ivpu_job.c b/drivers/accel/ivpu/ivpu_job.c
index 060f1fc031d3..7a1f78b84b09 100644
--- a/drivers/accel/ivpu/ivpu_job.c
+++ b/drivers/accel/ivpu/ivpu_job.c
@@ -574,7 +574,7 @@ static int ivpu_job_signal_and_destroy(struct ivpu_device *vdev, u32 job_id, u32
 		 * status and ensure both are handled in the same way
 		 */
 		job->file_priv->has_mmu_faults = true;
-		queue_work(system_wq, &vdev->context_abort_work);
+		queue_work(system_percpu_wq, &vdev->context_abort_work);
 		return 0;
 	}
 
diff --git a/drivers/accel/ivpu/ivpu_mmu.c b/drivers/accel/ivpu/ivpu_mmu.c
index 5ea010568faa..e1baf6b64935 100644
--- a/drivers/accel/ivpu/ivpu_mmu.c
+++ b/drivers/accel/ivpu/ivpu_mmu.c
@@ -970,7 +970,7 @@ void ivpu_mmu_irq_evtq_handler(struct ivpu_device *vdev)
 		}
 	}
 
-	queue_work(system_wq, &vdev->context_abort_work);
+	queue_work(system_percpu_wq, &vdev->context_abort_work);
 }
 
 void ivpu_mmu_evtq_dump(struct ivpu_device *vdev)
diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
index ffa2ba7cafe2..0cff8f808429 100644
--- a/drivers/accel/ivpu/ivpu_pm.c
+++ b/drivers/accel/ivpu/ivpu_pm.c
@@ -226,7 +226,7 @@ void ivpu_start_job_timeout_detection(struct ivpu_device *vdev)
 	unsigned long timeout_ms = ivpu_tdr_timeout_ms ? ivpu_tdr_timeout_ms : vdev->timeout.tdr;
 
 	/* No-op if already queued */
-	queue_delayed_work(system_wq, &vdev->pm->job_timeout_work, msecs_to_jiffies(timeout_ms));
+	queue_delayed_work(system_percpu_wq, &vdev->pm->job_timeout_work, msecs_to_jiffies(timeout_ms));
 }
 
 void ivpu_stop_job_timeout_detection(struct ivpu_device *vdev)
-- 
2.51.0

Re: [PATCH 2/2] accel/ivpu: replace use of system_wq with system_percpu_wq

[Karol Wachowski]

On 10/24/2025 11:52 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 consistentcy 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/accel/ivpu/ivpu_hw_btrs.c | 2 +-
>  drivers/accel/ivpu/ivpu_ipc.c     | 2 +-
>  drivers/accel/ivpu/ivpu_job.c     | 2 +-
>  drivers/accel/ivpu/ivpu_mmu.c     | 2 +-
>  drivers/accel/ivpu/ivpu_pm.c      | 2 +-
>  5 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/accel/ivpu/ivpu_hw_btrs.c b/drivers/accel/ivpu/ivpu_hw_btrs.c
> index afdb3b2aa72a..27a345f3befe 100644
> --- a/drivers/accel/ivpu/ivpu_hw_btrs.c
> +++ b/drivers/accel/ivpu/ivpu_hw_btrs.c
> @@ -673,7 +673,7 @@ bool ivpu_hw_btrs_irq_handler_lnl(struct ivpu_device *vdev, int irq)
>  
>  	if (REG_TEST_FLD(VPU_HW_BTRS_LNL_INTERRUPT_STAT, SURV_ERR, status)) {
>  		ivpu_dbg(vdev, IRQ, "Survivability IRQ\n");
> -		queue_work(system_wq, &vdev->irq_dct_work);
> +		queue_work(system_percpu_wq, &vdev->irq_dct_work);
>  	}
>  
>  	if (REG_TEST_FLD(VPU_HW_BTRS_LNL_INTERRUPT_STAT, FREQ_CHANGE, status)) {
> diff --git a/drivers/accel/ivpu/ivpu_ipc.c b/drivers/accel/ivpu/ivpu_ipc.c
> index 5f00809d448a..1f13bf95b2b3 100644
> --- a/drivers/accel/ivpu/ivpu_ipc.c
> +++ b/drivers/accel/ivpu/ivpu_ipc.c
> @@ -459,7 +459,7 @@ void ivpu_ipc_irq_handler(struct ivpu_device *vdev)
>  		}
>  	}
>  
> -	queue_work(system_wq, &vdev->irq_ipc_work);
> +	queue_work(system_percpu_wq, &vdev->irq_ipc_work);
>  }
>  
>  void ivpu_ipc_irq_work_fn(struct work_struct *work)
> diff --git a/drivers/accel/ivpu/ivpu_job.c b/drivers/accel/ivpu/ivpu_job.c
> index 060f1fc031d3..7a1f78b84b09 100644
> --- a/drivers/accel/ivpu/ivpu_job.c
> +++ b/drivers/accel/ivpu/ivpu_job.c
> @@ -574,7 +574,7 @@ static int ivpu_job_signal_and_destroy(struct ivpu_device *vdev, u32 job_id, u32
>  		 * status and ensure both are handled in the same way
>  		 */
>  		job->file_priv->has_mmu_faults = true;
> -		queue_work(system_wq, &vdev->context_abort_work);
> +		queue_work(system_percpu_wq, &vdev->context_abort_work);
>  		return 0;
>  	}
>  
> diff --git a/drivers/accel/ivpu/ivpu_mmu.c b/drivers/accel/ivpu/ivpu_mmu.c
> index 5ea010568faa..e1baf6b64935 100644
> --- a/drivers/accel/ivpu/ivpu_mmu.c
> +++ b/drivers/accel/ivpu/ivpu_mmu.c
> @@ -970,7 +970,7 @@ void ivpu_mmu_irq_evtq_handler(struct ivpu_device *vdev)
>  		}
>  	}
>  
> -	queue_work(system_wq, &vdev->context_abort_work);
> +	queue_work(system_percpu_wq, &vdev->context_abort_work);
>  }
>  
>  void ivpu_mmu_evtq_dump(struct ivpu_device *vdev)
> diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
> index ffa2ba7cafe2..0cff8f808429 100644
> --- a/drivers/accel/ivpu/ivpu_pm.c
> +++ b/drivers/accel/ivpu/ivpu_pm.c
> @@ -226,7 +226,7 @@ void ivpu_start_job_timeout_detection(struct ivpu_device *vdev)
>  	unsigned long timeout_ms = ivpu_tdr_timeout_ms ? ivpu_tdr_timeout_ms : vdev->timeout.tdr;
>  
>  	/* No-op if already queued */
> -	queue_delayed_work(system_wq, &vdev->pm->job_timeout_work, msecs_to_jiffies(timeout_ms));
> +	queue_delayed_work(system_percpu_wq, &vdev->pm->job_timeout_work, msecs_to_jiffies(timeout_ms));
Thanks for the patch. Please fix the checkpatch warning: 

WARNING: line length of 104 exceeds 100
columns                                                                           
#90: FILE:
drivers/accel/ivpu/ivpu_pm.c:229:                                                                              
+       queue_delayed_work(system_percpu_wq,
&vdev->pm->job_timeout_work, msecs_to_jiffies(timeout_ms));  
>  }
>  
>  void ivpu_stop_job_timeout_detection(struct ivpu_device *vdev)

Also there's a typo "consistentcy" -> "consistency" that can get fixed
with together with that warning.

Tested-by: Karol Wachowski <karol.wachowski@linux.intel.com>         

Re: [PATCH 2/2] accel/ivpu: replace use of system_wq with system_percpu_wq

[Marco Crivellari]

On Fri, Oct 24, 2025 at 12:49 PM Karol Wachowski
<karol.wachowski@linux.intel.com> wrote:
> [...]
> Thanks for the patch. Please fix the checkpatch warning:
>
> WARNING: line length of 104 exceeds 100
> columns
> Also there's a typo "consistentcy" -> "consistency" that can get fixed
> with together with that warning.
>
> [...]
> Tested-by: Karol Wachowski <karol.wachowski@linux.intel.com>
>
>

Hello Karol, thank you, I will fix both.

-- 

Marco Crivellari

L3 Support Engineer, Technology & Product