[PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Vlastimil Babka (SUSE)]

No module code calls these functions directly. Seems it was always the
case. Remove the exports.

Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
---
Based on slab/for-7.3/kfree_rcu_nolock
---
 mm/slab_common.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 6750dfa27367..cd155ffc2762 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1329,14 +1329,12 @@ void kvfree_rcu_barrier(void)
 	deferred_work_barrier();
 	rcu_barrier();
 }
-EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
 
 void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
 {
 	deferred_work_barrier();
 	rcu_barrier();
 }
-EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
 
 void __init kvfree_rcu_init(void)
 {
@@ -2163,7 +2161,6 @@ void kvfree_rcu_barrier(void)
 	flush_all_rcu_sheaves();
 	__kvfree_rcu_barrier();
 }
-EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
 
 /**
  * kvfree_rcu_barrier_on_cache - Wait for in-flight kvfree_rcu() calls on a
@@ -2186,7 +2183,6 @@ void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
 	rcu_barrier();
 	__kvfree_rcu_barrier();
 }
-EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
 
 static unsigned long
 kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)

---
base-commit: b01f6ed9ff0c4581fc669044fa5b82a93b4ef144
change-id: 20260730-unexport-barriers-439b3f69f791

Re: [PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Paul E. McKenney]

On Thu, Jul 30, 2026 at 04:32:46PM +0200, Vlastimil Babka (SUSE) wrote:
> No module code calls these functions directly. Seems it was always the
> case. Remove the exports.
> 
> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

Acked-by: Paul E. McKenney <paulmck@kernel.org>

Which reminds me...  Are you guys interested in taking the kfree_rcu()
test code from kernel/rcu/rcuscale.c?  See for example the kfree_rcu_test
module parameter.

							Thanx, Paul

> ---
> Based on slab/for-7.3/kfree_rcu_nolock
> ---
>  mm/slab_common.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 6750dfa27367..cd155ffc2762 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1329,14 +1329,12 @@ void kvfree_rcu_barrier(void)
>  	deferred_work_barrier();
>  	rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>  
>  void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
>  {
>  	deferred_work_barrier();
>  	rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
>  
>  void __init kvfree_rcu_init(void)
>  {
> @@ -2163,7 +2161,6 @@ void kvfree_rcu_barrier(void)
>  	flush_all_rcu_sheaves();
>  	__kvfree_rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>  
>  /**
>   * kvfree_rcu_barrier_on_cache - Wait for in-flight kvfree_rcu() calls on a
> @@ -2186,7 +2183,6 @@ void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
>  	rcu_barrier();
>  	__kvfree_rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
>  
>  static unsigned long
>  kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> 
> ---
> base-commit: b01f6ed9ff0c4581fc669044fa5b82a93b4ef144
> change-id: 20260730-unexport-barriers-439b3f69f791
> 
> 

Re: [PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Harry Yoo]

On Thu, Jul 30, 2026 at 04:32:46PM +0200, Vlastimil Babka (SUSE) wrote:
> No module code calls these functions directly. Seems it was always the
> case. Remove the exports.
> 
> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
> ---

Looks good to me,
Reviewed-by: Harry Yoo <harry@kernel.org>

-- 
Cheers,
Harry / Hyeonggon

Re: [PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Vlastimil Babka (SUSE)]

On 7/30/26 22:59, Paul E. McKenney wrote:
> On Thu, Jul 30, 2026 at 04:32:46PM +0200, Vlastimil Babka (SUSE) wrote:
>> No module code calls these functions directly. Seems it was always the
>> case. Remove the exports.
>> 
>> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
> 
> Acked-by: Paul E. McKenney <paulmck@kernel.org>

Thanks!

> Which reminds me...  Are you guys interested in taking the kfree_rcu()
> test code from kernel/rcu/rcuscale.c?  See for example the kfree_rcu_test
> module parameter.

Hmm, we have a slub kunit test, but I think no such torture/scaling test
infra. Maybe once we have that? What do you think, Harry?



> 							Thanx, Paul
> 
>> ---
>> Based on slab/for-7.3/kfree_rcu_nolock
>> ---
>>  mm/slab_common.c | 4 ----
>>  1 file changed, 4 deletions(-)
>> 
>> diff --git a/mm/slab_common.c b/mm/slab_common.c
>> index 6750dfa27367..cd155ffc2762 100644
>> --- a/mm/slab_common.c
>> +++ b/mm/slab_common.c
>> @@ -1329,14 +1329,12 @@ void kvfree_rcu_barrier(void)
>>  	deferred_work_barrier();
>>  	rcu_barrier();
>>  }
>> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>>  
>>  void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
>>  {
>>  	deferred_work_barrier();
>>  	rcu_barrier();
>>  }
>> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
>>  
>>  void __init kvfree_rcu_init(void)
>>  {
>> @@ -2163,7 +2161,6 @@ void kvfree_rcu_barrier(void)
>>  	flush_all_rcu_sheaves();
>>  	__kvfree_rcu_barrier();
>>  }
>> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>>  
>>  /**
>>   * kvfree_rcu_barrier_on_cache - Wait for in-flight kvfree_rcu() calls on a
>> @@ -2186,7 +2183,6 @@ void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
>>  	rcu_barrier();
>>  	__kvfree_rcu_barrier();
>>  }
>> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
>>  
>>  static unsigned long
>>  kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
>> 
>> ---
>> base-commit: b01f6ed9ff0c4581fc669044fa5b82a93b4ef144
>> change-id: 20260730-unexport-barriers-439b3f69f791
>> 
>> 

Re: [PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Vlastimil Babka (SUSE)]

On 7/30/26 16:32, Vlastimil Babka (SUSE) wrote:
> No module code calls these functions directly. Seems it was always the
> case. Remove the exports.
> 
> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
> ---
> Based on slab/for-7.3/kfree_rcu_nolock

Applied to that branch and slab/for-next

> ---
>  mm/slab_common.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 6750dfa27367..cd155ffc2762 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1329,14 +1329,12 @@ void kvfree_rcu_barrier(void)
>  	deferred_work_barrier();
>  	rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>  
>  void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
>  {
>  	deferred_work_barrier();
>  	rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
>  
>  void __init kvfree_rcu_init(void)
>  {
> @@ -2163,7 +2161,6 @@ void kvfree_rcu_barrier(void)
>  	flush_all_rcu_sheaves();
>  	__kvfree_rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
>  
>  /**
>   * kvfree_rcu_barrier_on_cache - Wait for in-flight kvfree_rcu() calls on a
> @@ -2186,7 +2183,6 @@ void kvfree_rcu_barrier_on_cache(struct kmem_cache *s)
>  	rcu_barrier();
>  	__kvfree_rcu_barrier();
>  }
> -EXPORT_SYMBOL_GPL(kvfree_rcu_barrier_on_cache);
>  
>  static unsigned long
>  kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> 
> ---
> base-commit: b01f6ed9ff0c4581fc669044fa5b82a93b4ef144
> change-id: 20260730-unexport-barriers-439b3f69f791
> 

Re: [PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Harry Yoo]

On Mon, Aug 03, 2026 at 09:59:44AM +0200, Vlastimil Babka (SUSE) wrote:
> On 7/30/26 22:59, Paul E. McKenney wrote:
> > On Thu, Jul 30, 2026 at 04:32:46PM +0200, Vlastimil Babka (SUSE) wrote:
> > Which reminds me...  Are you guys interested in taking the kfree_rcu()
> > test code from kernel/rcu/rcuscale.c?  See for example the kfree_rcu_test
> > module parameter.
> 
> Hmm, we have a slub kunit test, but I think no such torture/scaling test
> infra. Maybe once we have that? What do you think, Harry?

That'd be definitely useful. We have been reviving performance tests
every time we wondered if it'd affect performance in a surprising way.
But we've never put that in the mainline ;)

Probably test_kmalloc_nolock_and_friends*() don't even belong
slub_kunit.

Perhaps worth starting small with lib/test_slab.c, and slowly
move/add torture/scaling tests to there?

-- 
Cheers,
Harry / Hyeonggon

Re: [PATCH] mm/slab: stop exporting kvfree_rcu_barrier[_on_cache]()

[Paul E. McKenney]

On Mon, Aug 03, 2026 at 12:26:55PM +0000, Harry Yoo wrote:
> On Mon, Aug 03, 2026 at 09:59:44AM +0200, Vlastimil Babka (SUSE) wrote:
> > On 7/30/26 22:59, Paul E. McKenney wrote:
> > > On Thu, Jul 30, 2026 at 04:32:46PM +0200, Vlastimil Babka (SUSE) wrote:
> > > Which reminds me...  Are you guys interested in taking the kfree_rcu()
> > > test code from kernel/rcu/rcuscale.c?  See for example the kfree_rcu_test
> > > module parameter.
> > 
> > Hmm, we have a slub kunit test, but I think no such torture/scaling test
> > infra. Maybe once we have that? What do you think, Harry?
> 
> That'd be definitely useful. We have been reviving performance tests
> every time we wondered if it'd affect performance in a surprising way.
> But we've never put that in the mainline ;)
> 
> Probably test_kmalloc_nolock_and_friends*() don't even belong
> slub_kunit.
> 
> Perhaps worth starting small with lib/test_slab.c, and slowly
> move/add torture/scaling tests to there?

That would work for me.

							Thanx, Paul