Re: [PATCH v2 3/3] mm: add WQ_PERCPU to alloc_workqueue users

[Andrew Morton]

On Sat, 24 Jan 2026 23:21:35 +0100 Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:

> On 2026-01-13 12:46:30 [+0100], Marco Crivellari wrote:
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -8542,7 +8542,9 @@ void __init kmem_cache_init(void)
> >  
> >  void __init kmem_cache_init_late(void)
> >  {
> > -	flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
> > +#ifndef CONFIG_SLUB_TINY
> 
> This ifndef does not belong here.
> 
> > +	flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM | WQ_PERCPU,
> > +				  0);
> >  	WARN_ON(!flushwq);
> >  }

Yup, thanks, mm.git is carrying a -fix patch, which is actually wrong.


From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-add-wq_percpu-to-alloc_workqueue-users-fix
Date: Tue Jan 13 05:59:13 PM PST 2026

fix mm/slub.c

Cc: Marco Crivellari <marco.crivellari@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/slub.c |    1 +
 1 file changed, 1 insertion(+)

--- a/mm/slub.c~mm-add-wq_percpu-to-alloc_workqueue-users-fix
+++ a/mm/slub.c
@@ -8546,6 +8546,7 @@ void __init kmem_cache_init_late(void)
 	flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM | WQ_PERCPU,
 				  0);
 	WARN_ON(!flushwq);
+#endif
 }
 
 struct kmem_cache *



I'll add this:

--- a/mm/slub.c~mm-add-wq_percpu-to-alloc_workqueue-users-fix-fix
+++ a/mm/slub.c
@@ -8542,11 +8542,9 @@ void __init kmem_cache_init(void)
 
 void __init kmem_cache_init_late(void)
 {
-#ifndef CONFIG_SLUB_TINY
 	flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM | WQ_PERCPU,
 				  0);
 	WARN_ON(!flushwq);
-#endif
 }
 
 struct kmem_cache *
_