| From | Paul Gortmaker <> | Subject | [34-longterm 044/179] UBIFS: fix shrinker object count reports | Date | Mon, 14 May 2012 22:12:20 -0400 |
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From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
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: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/ubifs/shrinker.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/ubifs/shrinker.c b/fs/ubifs/shrinker.c index 02feb59..aec6689 100644 --- a/fs/ubifs/shrinker.c +++ b/fs/ubifs/shrinker.c @@ -283,7 +283,11 @@ int ubifs_shrinker(int nr, gfp_t gfp_mask) 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) { /* -- 1.7.9.6
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