From: Chen, Kenneth W <kenneth.w.chen@intel.com>
Date: Thu, 13 Oct 2005 19:49:29 +0000 (+0200)
Subject: Following the same idea, it occurs to me that we should only update
X-Git-Tag: v2.6.15-rc1~733^2~4^2~1
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b2982649ce38293b14684b26bcda20cfc54164e6;p=linux-2.6

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>
---

diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index c42071fd2e..4e2b1b06b4 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -2433,6 +2433,9 @@ void disk_round_stats(struct gendisk *disk)
 {
 	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));