commit b2982649ce38293b14684b26bcda20cfc54164e6
author Chen, Kenneth W <kenneth.w.chen@intel.com> Thu Oct 13 21:49:29 2005 +0200
committer Jens Axboe <axboe@nelson.home.kernel.dk> Fri Oct 28 08:15:43 2005 +0200
tree 8208c0cd33f2565f0f193d0afab282a7d0778382
parent 20e5c81fcff89535dced2ed71cf24c6c648ff40e

Following the same idea, it occurs to me that we should only update
disk stat when "now" is different from disk->stamp.  Otherwise, we
are again needlessly adding zero to the stats.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Jens Axboe <axboe@suse.de>

drivers/block/ll_rw_blk.c

diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index c42071f..4e2b1b0 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -2433,6 +2433,9 @@
 {
 	unsigned long now = jiffies;
 
+	if (now == disk->stamp)
+		return;
+
 	if (disk->in_flight) {
 		__disk_stat_add(disk, time_in_queue,
 				disk->in_flight * (now - disk->stamp));