linux-kernel - Re: [v8 PATCH 05/13] mm: vmscan: use kvfree_rcu instead of call

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Date:   Wed, 17 Feb 2021 09:25:18 +0300
From:   Kirill Tkhai <ktkhai@...tuozzo.com>
To:     Yang Shi <shy828301@...il.com>, guro@...com, vbabka@...e.cz,
        shakeelb@...gle.com, david@...morbit.com, hannes@...xchg.org,
        mhocko@...e.com, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [v8 PATCH 05/13] mm: vmscan: use kvfree_rcu instead of call_rcu

On 17.02.2021 03:13, Yang Shi wrote:
> Using kvfree_rcu() to free the old shrinker_maps instead of call_rcu().
> We don't have to define a dedicated callback for call_rcu() anymore.
> 
> Signed-off-by: Yang Shi <shy828301@...il.com>

Acked-by: Kirill Tkhai <ktkhai@...tuozzo.com>

> ---
>  mm/vmscan.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 2e753c2516fa..c2a309acd86b 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -192,11 +192,6 @@ static inline int shrinker_map_size(int nr_items)
>  	return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long));
>  }
>  
> -static void free_shrinker_map_rcu(struct rcu_head *head)
> -{
> -	kvfree(container_of(head, struct memcg_shrinker_map, rcu));
> -}
> -
>  static int expand_one_shrinker_map(struct mem_cgroup *memcg,
>  				   int size, int old_size)
>  {
> @@ -219,7 +214,7 @@ static int expand_one_shrinker_map(struct mem_cgroup *memcg,
>  		memset((void *)new->map + old_size, 0, size - old_size);
>  
>  		rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new);
> -		call_rcu(&old->rcu, free_shrinker_map_rcu);
> +		kvfree_rcu(old);
>  	}
>  
>  	return 0;
>