Re: [PATCH v5 06/13] fs: Propagate shrinker::id to list_lru

[Vladimir Davydov]

On Thu, May 10, 2018 at 12:53:06PM +0300, Kirill Tkhai wrote:
> The patch adds list_lru::shrinker_id field, and populates
> it by registered shrinker id.
> 
> This will be used to set correct bit in memcg shrinkers
> map by lru code in next patches, after there appeared
> the first related to memcg element in list_lru.
> 
> Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> ---
>  fs/super.c               |    4 ++++
>  include/linux/list_lru.h |    3 +++
>  mm/list_lru.c            |    6 ++++++
>  mm/workingset.c          |    3 +++
>  4 files changed, 16 insertions(+)
> 
> diff --git a/fs/super.c b/fs/super.c
> index 2ccacb78f91c..dfa85e725e45 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -258,6 +258,10 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
>  		goto fail;
>  	if (list_lru_init_memcg(&s->s_inode_lru))
>  		goto fail;
> +#ifdef CONFIG_MEMCG_SHRINKER
> +	s->s_dentry_lru.shrinker_id = s->s_shrink.id;
> +	s->s_inode_lru.shrinker_id = s->s_shrink.id;
> +#endif

I don't like this. Can't you simply pass struct shrinker to
list_lru_init_memcg() and let it extract the id?