2020-09-30 20:05:17

by Yang Shi

Subject: [PATCH] fs: nfs: return per memcg count for xattr shrinkers

The list_lru_count() returns the pre node count, but the new xattr
shrinkers are memcg aware, so the shrinkers should return per memcg
count by calling list_lru_shrink_count() instead. Otherwise over-shrink
might be experienced. The problem was spotted by visual code
inspection.

Cc: Trond Myklebust <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: Frank van der Linden <[email protected]>
Signed-off-by: Yang Shi <[email protected]>
---
fs/nfs/nfs42xattr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
index 86777996cfec..6e5f34916937 100644
--- a/fs/nfs/nfs42xattr.c
+++ b/fs/nfs/nfs42xattr.c
@@ -882,7 +882,7 @@ nfs4_xattr_cache_count(struct shrinker *shrink, struct shrink_control *sc)
{
unsigned long count;

- count = list_lru_count(&nfs4_xattr_cache_lru);
+ count = list_lru_shrink_count(&nfs4_xattr_cache_lru, sc);
return vfs_pressure_ratio(count);
}

@@ -976,7 +976,7 @@ nfs4_xattr_entry_count(struct shrinker *shrink, struct shrink_control *sc)
lru = (shrink == &nfs4_xattr_large_entry_shrinker) ?
&nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;

- count = list_lru_count(lru);
+ count = list_lru_shrink_count(lru, sc);
return vfs_pressure_ratio(count);
}

--
2.26.2

2020-09-30 20:47:40

by Frank van der Linden

Subject: Re: [PATCH] fs: nfs: return per memcg count for xattr shrinkers

On Sun, Sep 27, 2020 at 04:42:20AM -0700, Yang Shi wrote:
>
> The list_lru_count() returns the pre node count, but the new xattr
> shrinkers are memcg aware, so the shrinkers should return per memcg
> count by calling list_lru_shrink_count() instead. Otherwise over-shrink
> might be experienced. The problem was spotted by visual code
> inspection.
>
> Cc: Trond Myklebust <[email protected]>
> Cc: Anna Schumaker <[email protected]>
> Cc: Frank van der Linden <[email protected]>
> Signed-off-by: Yang Shi <[email protected]>
> ---
> fs/nfs/nfs42xattr.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
> index 86777996cfec..6e5f34916937 100644
> --- a/fs/nfs/nfs42xattr.c
> +++ b/fs/nfs/nfs42xattr.c
> @@ -882,7 +882,7 @@ nfs4_xattr_cache_count(struct shrinker *shrink, struct shrink_control *sc)
> {
> unsigned long count;
>
> - count = list_lru_count(&nfs4_xattr_cache_lru);
> + count = list_lru_shrink_count(&nfs4_xattr_cache_lru, sc);
> return vfs_pressure_ratio(count);
> }
>
> @@ -976,7 +976,7 @@ nfs4_xattr_entry_count(struct shrinker *shrink, struct shrink_control *sc)
> lru = (shrink == &nfs4_xattr_large_entry_shrinker) ?
> &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
>
> - count = list_lru_count(lru);
> + count = list_lru_shrink_count(lru, sc);
> return vfs_pressure_ratio(count);
> }
>
> --
> 2.26.2
>

Yep, thanks.

Reviewed-by: Frank van der Linden <[email protected]>