From: Joe Thornber Date: Tue, 30 Sep 2014 08:32:46 +0000 (+0100) Subject: dm bufio: update last_accessed when relinking a buffer X-Git-Tag: firefly_0821_release~3679^2~1292 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3f626317894a923edea99de4f18590c008375890;p=firefly-linux-kernel-4.4.55.git dm bufio: update last_accessed when relinking a buffer commit eb76faf53b1ff7a77ce3f78cc98ad392ac70c2a0 upstream. The 'last_accessed' member of the dm_buffer structure was only set when the the buffer was created. This led to each buffer being discarded after dm_bufio_max_age time even if it was used recently. In practice this resulted in all thinp metadata being evicted soon after being read -- this is particularly problematic for metadata intensive workloads like multithreaded small random IO. 'last_accessed' is now updated each time the buffer is moved to the head of the LRU list, so the buffer is now properly discarded if it was not used in dm_bufio_max_age time. Signed-off-by: Joe Thornber Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index a6e985fcceb8..c9b4ca9e0696 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -462,6 +462,7 @@ static void __relink_lru(struct dm_buffer *b, int dirty) c->n_buffers[dirty]++; b->list_mode = dirty; list_move(&b->lru_list, &c->lru[dirty]); + b->last_accessed = jiffies; } /*----------------------------------------------------------------