Re: [PATCH RFC 02/12] mm/slab: remove objs_per_slab()

On Wed, Jul 15, 2026 at 3:10 AM Vlastimil Babka (SUSE)
<[email protected]> 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.
>
> Signed-off-by: Vlastimil Babka (SUSE) <[email protected]>

Reviewed-by: Suren Baghdasayan <[email protected]>

> ---
>  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 a4be70d080fb..9e25f2dce7a6 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2127,7 +2127,6 @@ 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;
> @@ -2183,7 +2182,7 @@ 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
>