| From | Andi Kleen <> | Subject | [PATCH] [34/99] UBIFS: fix shrinker object count reports | Date | Wed, 27 Jul 2011 14:48:32 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
commit cf610bf4199770420629d3bc273494bd27ad6c1d upstream.
Sometimes VM asks the shrinker to return amount of objects it can shrink, and we return the ubifs_clean_zn_cnt in that case. However, it is possible that this counter is negative for a short period of time, due to the way UBIFS TNC code updates it. And I can observe the following warnings sometimes:
shrink_slab: ubifs_shrinker+0x0/0x2b7 [ubifs] negative objects to delete nr=-8541616642706119788
This patch makes sure UBIFS never returns negative count of objects.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- fs/ubifs/shrinker.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
Index: linux-2.6.35.y/fs/ubifs/shrinker.c =================================================================== --- linux-2.6.35.y.orig/fs/ubifs/shrinker.c +++ linux-2.6.35.y/fs/ubifs/shrinker.c @@ -283,7 +283,11 @@ int ubifs_shrinker(struct shrinker *shri long clean_zn_cnt = atomic_long_read(&ubifs_clean_zn_cnt); if (nr == 0) - return clean_zn_cnt; + /* + * Due to the way UBIFS updates the clean znode counter it may + * temporarily be negative. + */ + return clean_zn_cnt >= 0 ? clean_zn_cnt : 1; if (!clean_zn_cnt) { /*
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