linux-kernel - Re: [PATCH] slub: let need_slab_obj_exts() return false if SLAB_NO_OBJ

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Message-ID: <aYU7l6P2ikKvnrWT@hyeyoo>
Date: Fri, 6 Feb 2026 09:53:43 +0900
From: Harry Yoo <harry.yoo@...cle.com>
To: Hao Li <hao.li@...ux.dev>
Cc: vbabka@...e.cz, akpm@...ux-foundation.org, cl@...two.org,
        rientjes@...gle.com, roman.gushchin@...ux.dev, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] slub: let need_slab_obj_exts() return false if
 SLAB_NO_OBJ_EXT is set

On Thu, Feb 05, 2026 at 08:07:23PM +0800, Hao Li wrote:
> SLAB_NO_OBJ_EXT is set for boot caches, but need_slab_obj_exts() doesn't
> check this flag. We should return false unconditionally when
> SLAB_NO_OBJ_EXT is set.
> 
> Signed-off-by: Hao Li <hao.li@...ux.dev>
> ---

Looks reasonable to me,
Acked-by: Harry Yoo <harry.yoo@...cle.com>

Thanks!

>  mm/slub.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 865047eaf02b..3b1402e1c39d 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -901,6 +901,9 @@ static inline unsigned long get_orig_size(struct kmem_cache *s, void *object)
>   */
>  static inline bool need_slab_obj_exts(struct kmem_cache *s)
>  {
> +	if (s->flags & SLAB_NO_OBJ_EXT)
> +		return false;
> +
>  	if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
>  		return true;
>  

-- 
Cheers,
Harry / Hyeonggon