Re: [PATCH v3 02/13] mm/slab: remove objs_per_slab()

[Hao Li <hao.li@linux.dev>]

On Mon, Jul 27, 2026 at 02:53:56PM +0200, Vlastimil Babka (SUSE) wrote:
> The function has an unused kmem_cache argument and almost nothing uses
> it anyway; doing slab->objects is simpler. Remove it with the last two
> users. KUNIT_EXPECT_EQ() needs a cast to avoid "error: ‘typeof’ applied
> to a bit-field" but we don't need to keep a wrapper just for that.
> 
> Reviewed-by: Suren Baghdasaryan <surenb@google.com>
> Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
> Reviewed-by: Hao Li <hao.li@linux.dev>
> Reviewed-by: Suren Baghdasayan <surenb@google.com>

Oops, the r-b tag got duplicated :)

> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
> ---
>  mm/kfence/kfence_test.c | 2 +-
>  mm/slab.h               | 6 ------
>  mm/slub.c               | 3 +--
>  3 files changed, 2 insertions(+), 9 deletions(-)
> 
> diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
> index de2d0f7d62b1..9867c03ef0ae 100644
> --- a/mm/kfence/kfence_test.c
> +++ b/mm/kfence/kfence_test.c
> @@ -295,7 +295,7 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
>  			 * memcg accounting works correctly.
>  			 */
>  			KUNIT_EXPECT_EQ(test, obj_to_index(s, slab, alloc), 0U);
> -			KUNIT_EXPECT_EQ(test, objs_per_slab(s, slab), 1);
> +			KUNIT_EXPECT_EQ(test, ((unsigned int)slab->objects), 1);
>  
>  			if (policy == ALLOCATE_ANY)
>  				return alloc;
> diff --git a/mm/slab.h b/mm/slab.h
> index f5e336b6b6b0..01535e1e2d3c 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -330,12 +330,6 @@ static inline unsigned int obj_to_index(const struct kmem_cache *cache,
>  	return __obj_to_index(cache, slab_address(slab), obj);
>  }
>  
> -static inline int objs_per_slab(const struct kmem_cache *cache,
> -				const struct slab *slab)
> -{
> -	return slab->objects;
> -}
> -
>  /*
>   * State of the slab allocator.
>   *
> diff --git a/mm/slub.c b/mm/slub.c
> index d702d273253c..b94482830637 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2130,7 +2130,6 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
>  			gfp_t gfp, unsigned int alloc_flags)
>  {
>  	const bool allow_spin = alloc_flags_allow_spinning(alloc_flags);
> -	unsigned int objects = objs_per_slab(s, slab);
>  	bool new_slab = alloc_flags & SLAB_ALLOC_NEW_SLAB;
>  	unsigned long new_exts;
>  	unsigned long old_exts;
> @@ -2186,7 +2185,7 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
>  #endif
>  retry:
>  	old_exts = READ_ONCE(slab->obj_exts);
> -	handle_failed_objexts_alloc(old_exts, vec, objects);
> +	handle_failed_objexts_alloc(old_exts, vec, slab->objects);
>  
>  	if (new_slab) {
>  		/*
> 
> -- 
> 2.55.0
> 

-- 
Thanks,
Hao