Re: [PATCH 2/3] mm/slab: delete cache_alloc_debugcheck_before()

[Vlastimil Babka]

On 6/5/22 17:25, Daniel Vetter wrote:
> It only does a might_sleep_if(GFP_RECLAIM) check, which is already
> covered by the might_alloc() in slab_pre_alloc_hook(). And all callers
> of cache_alloc_debugcheck_before() call that beforehand already.
> 
> Signed-off-by: Daniel Vetter 
> Cc: Christoph Lameter 
> Cc: Pekka Enberg 
> Cc: David Rientjes 
> Cc: Joonsoo Kim 
> Cc: Andrew Morton 
> Cc: Vlastimil Babka 
> Cc: Roman Gushchin 
> Cc: linux...@kvack.org

Thanks, added to slab/for-5.20/cleanup as it's slab-specific and independent
from 1/3 and 3/3.

> ---
>  mm/slab.c | 10 --
>  1 file changed, 10 deletions(-)
> 
> diff --git a/mm/slab.c b/mm/slab.c
> index b04e40078bdf..75779ac5f5ba 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -2973,12 +2973,6 @@ static void *cache_alloc_refill(struct kmem_cache 
> *cachep, gfp_t flags)
>   return ac->entry[--ac->avail];
>  }
>  
> -static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
> - gfp_t flags)
> -{
> - might_sleep_if(gfpflags_allow_blocking(flags));
> -}
> -
>  #if DEBUG
>  static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
>   gfp_t flags, void *objp, unsigned long caller)
> @@ -3219,7 +3213,6 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, 
> int nodeid, size_t orig_
>   if (unlikely(ptr))
>   goto out_hooks;
>  
> - cache_alloc_debugcheck_before(cachep, flags);
>   local_irq_save(save_flags);
>  
>   if (nodeid == NUMA_NO_NODE)
> @@ -3304,7 +3297,6 @@ slab_alloc(struct kmem_cache *cachep, struct list_lru 
> *lru, gfp_t flags,
>   if (unlikely(objp))
>   goto out;
>  
> - cache_alloc_debugcheck_before(cachep, flags);
>   local_irq_save(save_flags);
>   objp = __do_cache_alloc(cachep, flags);
>   local_irq_restore(save_flags);
> @@ -3541,8 +3533,6 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t 
> flags, size_t size,
>   if (!s)
>   return 0;
>  
> - cache_alloc_debugcheck_before(s, flags);
> -
>   local_irq_disable();
>   for (i = 0; i < size; i++) {
>   void *objp = kfence_alloc(s, s->object_size, flags) ?: 
> __do_cache_alloc(s, flags);

Re: [PATCH 2/3] mm/slab: delete cache_alloc_debugcheck_before()

[Muchun Song]

On Sun, Jun 05, 2022 at 05:25:38PM +0200, Daniel Vetter wrote:
> It only does a might_sleep_if(GFP_RECLAIM) check, which is already
> covered by the might_alloc() in slab_pre_alloc_hook(). And all callers
> of cache_alloc_debugcheck_before() call that beforehand already.
> 
> Signed-off-by: Daniel Vetter 

Nice cleanup.

Reviewed-by: Muchun Song 

Thanks.

Re: [PATCH 2/3] mm/slab: delete cache_alloc_debugcheck_before()

[David Hildenbrand]

On 05.06.22 17:25, Daniel Vetter wrote:
> It only does a might_sleep_if(GFP_RECLAIM) check, which is already
> covered by the might_alloc() in slab_pre_alloc_hook(). And all callers
> of cache_alloc_debugcheck_before() call that beforehand already.
> 
> Signed-off-by: Daniel Vetter 
> Cc: Christoph Lameter 
> Cc: Pekka Enberg 
> Cc: David Rientjes 
> Cc: Joonsoo Kim 
> Cc: Andrew Morton 
> Cc: Vlastimil Babka 
> Cc: Roman Gushchin 
> Cc: linux...@kvack.org
> ---

LGTM

Reviewed-by: David Hildenbrand 

-- 
Thanks,

David / dhildenb

[PATCH 2/3] mm/slab: delete cache_alloc_debugcheck_before()

[Daniel Vetter]

It only does a might_sleep_if(GFP_RECLAIM) check, which is already
covered by the might_alloc() in slab_pre_alloc_hook(). And all callers
of cache_alloc_debugcheck_before() call that beforehand already.

Signed-off-by: Daniel Vetter 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Andrew Morton 
Cc: Vlastimil Babka 
Cc: Roman Gushchin 
Cc: linux...@kvack.org
---
 mm/slab.c | 10 --
 1 file changed, 10 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index b04e40078bdf..75779ac5f5ba 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2973,12 +2973,6 @@ static void *cache_alloc_refill(struct kmem_cache 
*cachep, gfp_t flags)
return ac->entry[--ac->avail];
 }
 
-static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
-   gfp_t flags)
-{
-   might_sleep_if(gfpflags_allow_blocking(flags));
-}
-
 #if DEBUG
 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
gfp_t flags, void *objp, unsigned long caller)
@@ -3219,7 +3213,6 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, 
int nodeid, size_t orig_
if (unlikely(ptr))
goto out_hooks;
 
-   cache_alloc_debugcheck_before(cachep, flags);
local_irq_save(save_flags);
 
if (nodeid == NUMA_NO_NODE)
@@ -3304,7 +3297,6 @@ slab_alloc(struct kmem_cache *cachep, struct list_lru 
*lru, gfp_t flags,
if (unlikely(objp))
goto out;
 
-   cache_alloc_debugcheck_before(cachep, flags);
local_irq_save(save_flags);
objp = __do_cache_alloc(cachep, flags);
local_irq_restore(save_flags);
@@ -3541,8 +3533,6 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t 
flags, size_t size,
if (!s)
return 0;
 
-   cache_alloc_debugcheck_before(s, flags);
-
local_irq_disable();
for (i = 0; i < size; i++) {
void *objp = kfence_alloc(s, s->object_size, flags) ?: 
__do_cache_alloc(s, flags);
-- 
2.36.0