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* [PATCH] fs: nfs: return per memcg count for xattr shrinkers
@ 2020-09-27 11:42 Yang Shi
  2020-09-30 20:46 ` Frank van der Linden
  0 siblings, 1 reply; 2+ messages in thread
From: Yang Shi @ 2020-09-27 11:42 UTC (permalink / raw)
  To: trond.myklebust, anna.schumaker, fllinden
  Cc: shy828301, linux-nfs, linux-fsdevel, linux-kernel

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 <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 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


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] fs: nfs: return per memcg count for xattr shrinkers
  2020-09-27 11:42 [PATCH] fs: nfs: return per memcg count for xattr shrinkers Yang Shi
@ 2020-09-30 20:46 ` Frank van der Linden
  0 siblings, 0 replies; 2+ messages in thread
From: Frank van der Linden @ 2020-09-30 20:46 UTC (permalink / raw)
  To: Yang Shi
  Cc: trond.myklebust, anna.schumaker, linux-nfs, linux-fsdevel, linux-kernel

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 <trond.myklebust@hammerspace.com>
> Cc: Anna Schumaker <anna.schumaker@netapp.com>
> Cc: Frank van der Linden <fllinden@amazon.com>
> Signed-off-by: Yang Shi <shy828301@gmail.com>
> ---
>  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 <fllinden@amazon.com>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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