Re: [PATCH] mm: memcontrol: factor out memcg kmem uncharge sequence

[Tao Cui <cui.tao@linux.dev>]

在 2026/7/13 17:03, Guopeng Zhang 写道:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
> 
> The kmem-uncharge sequence (mod_memcg_state(MEMCG_KMEM) +
> memcg1_account_kmem + conditional memcg_uncharge) is duplicated verbatim
> in obj_cgroup_release() and drain_obj_stock_slot(). Factor it into a
> small memcg_uncharge_kmem() helper. The reference get/put stays at the
> call sites, as they differ.
> 
> No functional change.

Acked-by: Tao Cui <cuitao@kylinos.cn>

> 
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
> ---
>  mm/memcontrol.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 22f55aeb94f3..86acfe55a201 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -137,6 +137,14 @@ bool mem_cgroup_kmem_disabled(void)
>  
>  static void memcg_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages);
>  
> +static void memcg_uncharge_kmem(struct mem_cgroup *memcg, unsigned int nr_pages)
> +{
> +	mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
> +	memcg1_account_kmem(memcg, -nr_pages);
> +	if (!mem_cgroup_is_root(memcg))
> +		memcg_uncharge(memcg, nr_pages);
> +}
> +
>  static void obj_cgroup_release(struct percpu_ref *ref)
>  {
>  	struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
> @@ -172,10 +180,7 @@ static void obj_cgroup_release(struct percpu_ref *ref)
>  		struct mem_cgroup *memcg;
>  
>  		memcg = get_mem_cgroup_from_objcg(objcg);
> -		mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
> -		memcg1_account_kmem(memcg, -nr_pages);
> -		if (!mem_cgroup_is_root(memcg))
> -			memcg_uncharge(memcg, nr_pages);
> +		memcg_uncharge_kmem(memcg, nr_pages);
>  		mem_cgroup_put(memcg);
>  	}
>  
> @@ -3329,10 +3334,7 @@ static void drain_obj_stock_slot(struct obj_stock_pcp *stock, int i)
>  
>  			memcg = get_mem_cgroup_from_objcg(old);
>  
> -			mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);
> -			memcg1_account_kmem(memcg, -nr_pages);
> -			if (!mem_cgroup_is_root(memcg))
> -				memcg_uncharge(memcg, nr_pages);
> +			memcg_uncharge_kmem(memcg, nr_pages);
>  
>  			css_put(&memcg->css);
>  		}