Re: [PATCH v4 14/16] memcg: Convert mem_cgroup_from_obj_folio() to mem_cgroup_from_obj_slab()

[Johannes Weiner <hannes@cmpxchg.org>]

On Thu, Nov 13, 2025 at 04:39:41PM +0000, Matthew Wilcox wrote:
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2599,9 +2599,6 @@ struct mem_cgroup *mem_cgroup_from_obj_slab(struct slab *slab, void *p)
>  	struct slabobj_ext *obj_exts;
>  	unsigned int off;
>  
> -	if (!slab)
> -		return NULL;
> -
>  	obj_exts = slab_obj_exts(slab);
>  	if (!obj_exts)
>  		return NULL;
> @@ -2624,10 +2621,15 @@ struct mem_cgroup *mem_cgroup_from_obj_slab(struct slab *slab, void *p)
>   */
>  struct mem_cgroup *mem_cgroup_from_slab_obj(void *p)
>  {
> +	struct slab *slab;
> +
>  	if (mem_cgroup_disabled())
>  		return NULL;
>  
> -	return mem_cgroup_from_obj_slab(virt_to_slab(p), p);
> +	slab = virt_to_slab(p);
> +	if (slab)
> +		return mem_cgroup_from_obj_slab(slab, p);
> +	return folio_memcg_check(virt_to_folio(p));

Looks good to me, thanks!

With that folded in, for the combined patch:

Acked-by: Johannes Weiner <hannes@cmpxchg.org>