Re: [PATCH v2 26/28] mm: memcontrol: refactor memcg_reparent_objcgs()

[Johannes Weiner]

On Wed, Dec 17, 2025 at 03:27:50PM +0800, Qi Zheng wrote:
> +static void memcg_reparent_objcgs(struct mem_cgroup *src)
> +{
> +	struct obj_cgroup *objcg = rcu_dereference_protected(src->objcg, true);
> +	struct mem_cgroup *dst = parent_mem_cgroup(src);
> +
> +	reparent_locks(src, dst);
> +
> +	__memcg_reparent_objcgs(src, dst);

Please have __memcg_reparent_objcgs() return the dead objcg for the
percpu_ref_kill(), instead of doing the deref twice.

And please use @child, @parent (or @memcg, @parent) throughout instead
of @src and @dst.

> +
> +	reparent_unlocks(src, dst);
>  
>  	percpu_ref_kill(&objcg->refcnt);

With that,

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>