Re: [v7 PATCH 09/12] mm: vmscan: use per memcg nr_deferred of shrinker

[Roman Gushchin]

On Tue, Feb 09, 2021 at 09:46:43AM -0800, Yang Shi wrote:
> Use per memcg's nr_deferred for memcg aware shrinkers.  The shrinker's nr_deferred
> will be used in the following cases:
>     1. Non memcg aware shrinkers
>     2. !CONFIG_MEMCG
>     3. memcg is disabled by boot parameter
> 
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
> ---
>  mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 66 insertions(+), 12 deletions(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index d4b030a0b2a9..748aa6e90f83 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -368,6 +368,24 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker)
>  	up_write(&shrinker_rwsem);
>  }
>  
> +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker,
> +				    struct mem_cgroup *memcg)

"Count" is not associated with xchg() semantics in my head, but I don't know
what's the better version. Maybe steal or pop?

Otherwise the patch looks good to me.

Thanks!