[PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

Hi,

Recently the workqueue code has been changed introducing two new workqueue,
system_percpu_wq and system_dfl_wq, as a future replacement for system_wq and
system_unbound_wq respectively, and a new flag, alloc_workqueue() WQ_PERCPU.
This flag must be used when WQ_UNBOUND is not present, making explicit the
workqueue is per-cpu.

The changes has been introduced by:
    commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
    commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

The old workqueue(s) will be removed in a next release cycle.

=== Introduced Changes by this series ===

1) [P 1-2] add WQ_PERCPU to alloc_workqueue()

    This change adds a new WQ_PERCPU flag to explicitly request
    alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified.


Thanks!

---
Changes in v2:
- patches unified in 1 series
- rebase on v7.0-rc1


Marco Crivellari (2):
  block: Add WQ_PERCPU to alloc_workqueue users
  block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users

 block/bio-integrity-auto.c | 2 +-
 block/bio.c                | 2 +-
 block/blk-core.c           | 2 +-
 block/blk-throttle.c       | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

-- 
2.52.0

[PATCH v2 1/2] block: Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

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")

The refactoring is going to alter the default behavior of
alloc_workqueue() to be unbound by default.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU. For more details see the Link tag below.

In order to keep alloc_workqueue() behavior identical, explicitly request
WQ_PERCPU.

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>
---
 block/bio-integrity-auto.c | 2 +-
 block/bio.c                | 2 +-
 block/blk-core.c           | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/bio-integrity-auto.c b/block/bio-integrity-auto.c
index 44dcdf7520c5..a2bccb3c4baa 100644
--- a/block/bio-integrity-auto.c
+++ b/block/bio-integrity-auto.c
@@ -183,7 +183,7 @@ static int __init blk_integrity_auto_init(void)
 	 * Make it highpri CPU intensive wq with max concurrency of 1.
 	 */
 	kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
-					 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
+					 WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_PERCPU, 1);
 	if (!kintegrityd_wq)
 		panic("Failed to create kintegrityd\n");
 	return 0;
diff --git a/block/bio.c b/block/bio.c
index d80d5d26804e..fd8073fbffb2 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1956,7 +1956,7 @@ int bioset_init(struct bio_set *bs,
 
 	if (flags & BIOSET_NEED_RESCUER) {
 		bs->rescue_workqueue = alloc_workqueue("bioset",
-							WQ_MEM_RECLAIM, 0);
+							WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 		if (!bs->rescue_workqueue)
 			goto bad;
 	}
diff --git a/block/blk-core.c b/block/blk-core.c
index 474700ffaa1c..17450058ea6d 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1282,7 +1282,7 @@ int __init blk_dev_init(void)
 
 	/* used for unplugging and affects IO latency/throughput - HIGHPRI */
 	kblockd_workqueue = alloc_workqueue("kblockd",
-					    WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
+					    WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_PERCPU, 0);
 	if (!kblockd_workqueue)
 		panic("Failed to create kblockd\n");
 
-- 
2.52.0

[PATCH v2 2/2] block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

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")

The refactoring is going to alter the default behavior of
alloc_workqueue() to be unbound by default.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU. For more details see the Link tag below.

In order to keep alloc_workqueue() behavior identical, explicitly request
WQ_PERCPU.

Cc: Josef Bacik <josef@toxicpanda.com>
Cc: cgroups@vger.kernel.org
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>
---
 block/blk-throttle.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 97188a795848..cabf91f0d0dc 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1839,7 +1839,7 @@ void blk_throtl_exit(struct gendisk *disk)
 
 static int __init throtl_init(void)
 {
-	kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0);
+	kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 	if (!kthrotld_workqueue)
 		panic("Failed to create kthrotld\n");
 
-- 
2.52.0

Re: [PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

On Mon, Feb 23, 2026 at 10:29 AM Marco Crivellari
<marco.crivellari@suse.com> wrote:
> [...]
> Marco Crivellari (2):
>   block: Add WQ_PERCPU to alloc_workqueue users
>   block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users

Hi,

Gentle ping.

Thanks!


-- 

Marco Crivellari

L3 Support Engineer

Re: [PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

On Mon, Feb 23, 2026 at 10:29 AM Marco Crivellari
<marco.crivellari@suse.com> wrote:
> [...]
> Marco Crivellari (2):
>   block: Add WQ_PERCPU to alloc_workqueue users
>   block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users
>
>  block/bio-integrity-auto.c | 2 +-
>  block/bio.c                | 2 +-
>  block/blk-core.c           | 2 +-
>  block/blk-throttle.c       | 2 +-
>  4 files changed, 4 insertions(+), 4 deletions(-)

Hi,

Gentle ping.

Thanks!


-- 

Marco Crivellari

L3 Support Engineer

Re: [PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

On Mon, Feb 23, 2026 at 10:29 AM Marco Crivellari
<marco.crivellari@suse.com> wrote:
> [...]
> Marco Crivellari (2):
>   block: Add WQ_PERCPU to alloc_workqueue users
>   block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users
>
>  block/bio-integrity-auto.c | 2 +-
>  block/bio.c                | 2 +-
>  block/blk-core.c           | 2 +-
>  block/blk-throttle.c       | 2 +-
>  4 files changed, 4 insertions(+), 4 deletions(-)

Hi,

Gentle ping.

Thanks!


-- 

Marco Crivellari

SUSE Labs

Re: [PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[Jens Axboe]

On Mon, 23 Feb 2026 10:29:18 +0100, Marco Crivellari wrote:
> Recently the workqueue code has been changed introducing two new workqueue,
> system_percpu_wq and system_dfl_wq, as a future replacement for system_wq and
> system_unbound_wq respectively, and a new flag, alloc_workqueue() WQ_PERCPU.
> This flag must be used when WQ_UNBOUND is not present, making explicit the
> workqueue is per-cpu.
> 
> The changes has been introduced by:
>     commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
>     commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")
> 
> [...]

Applied, thanks!

[1/2] block: Add WQ_PERCPU to alloc_workqueue users
      commit: 98236343bb5dbbf3fcb3260795be2bbb1e3d2001
[2/2] block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users
      commit: 19d32966e1f68623ac9d95fbcf34b1fb1a7be48d

Best regards,
-- 
Jens Axboe

Re: [PATCH v2 0/2] Add WQ_PERCPU to alloc_workqueue users

[Marco Crivellari]

On Fri, Apr 17, 2026 at 10:39 PM Jens Axboe <axboe@kernel.dk> wrote:
> [...]
> Applied, thanks!
>
> [1/2] block: Add WQ_PERCPU to alloc_workqueue users
>       commit: 98236343bb5dbbf3fcb3260795be2bbb1e3d2001
> [2/2] block/blk-throttle: Add WQ_PERCPU to alloc_workqueue users
>       commit: 19d32966e1f68623ac9d95fbcf34b1fb1a7be48d

Many thanks!

-- 

Marco Crivellari

SUSE Labs