[PATCH v4 1/2] mm: introduce helper to check slub_debug_enabled

[Marco Elver]

On Fri, 2 Jul 2021 at 10:54, <yee.lee at mediatek.com> wrote:
>
> From: Marco Elver <elver at google.com>
>
> Introduce a helper to check slub_debug_enabled, so that we can confine
> the use of #ifdef to the definition of the slub_debug_enabled_unlikely()
> helper.
>
> ---

^^ this '---' is wrong. It needs to be removed, because anything after
the first '---' will be discarded if it is turned into a commit by the
maintainer.


> Signed-off-by: Marco Elver <elver at google.com>
> Signed-off-by: Yee Lee <yee.lee at mediatek.com>
>
> ---
>  mm/slab.h | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/mm/slab.h b/mm/slab.h
> index 7b60ef2f32c3..a11126afe24c 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -216,10 +216,18 @@ DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
>  #endif
>  extern void print_tracking(struct kmem_cache *s, void *object);
>  long validate_slab_cache(struct kmem_cache *s);
> +static inline bool slub_debug_enabled_unlikely(void)
> +{
> +       return static_branch_unlikely(&slub_debug_enabled);
> +}
>  #else
>  static inline void print_tracking(struct kmem_cache *s, void *object)
>  {
>  }
> +static inline bool slub_debug_enabled_unlikely(void)
> +{
> +       return false;
> +}
>  #endif
>
>  /*
> @@ -229,11 +237,10 @@ static inline void print_tracking(struct kmem_cache *s, void *object)
>   */
>  static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
>  {
> -#ifdef CONFIG_SLUB_DEBUG
> -       VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
> -       if (static_branch_unlikely(&slub_debug_enabled))
> +       if (IS_ENABLED(CONFIG_SLUB_DEBUG))
> +               VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
> +       if (slub_debug_enabled_unlikely())
>                 return s->flags & flags;
> -#endif
>         return false;
>  }
>
> --
> 2.18.0