From 74672d069b298b03e9f657fd70915e055739882e Mon Sep 17 00:00:00 2001
From: Gu Zheng <guz.fnst@cn.fujitsu.com>
Date: Fri, 3 Apr 2015 08:44:47 +0800
Subject: [PATCH] md: fix md io stats accounting broken
Simon reported the md io stats accounting issue:
"
I'm seeing "iostat -x -k 1" print this after a RAID1 rebuild on 4.0-rc5.
It's not abnormal other than it's 3-disk, with one being SSD (sdc) and
the other two being write-mostly:
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
md0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 345.00 0.00 0.00 0.00 0.00 100.00
md2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 58779.00 0.00 0.00 0.00 0.00 100.00
md1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 12.00 0.00 0.00 0.00 0.00 100.00
"
The cause is commit "18c0b223cf9901727ef3b02da6711ac930b4e5d4" uses the
generic_start_io_acct to account the disk stats rather than the open code,
but it also introduced the increase to .in_flight[rw] which is needless to
md. So we re-use the open code here to fix it.
Reported-by: Simon Kirby <sim@hostway.ca>
Cc: <stable@vger.kernel.org> 3.19
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
drivers/md/md.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 717daad71fb1..e6178787ce3d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -249,6 +249,7 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
const int rw = bio_data_dir(bio);
struct mddev *mddev = q->queuedata;
unsigned int sectors;
+ int cpu;
if (mddev == NULL || mddev->pers == NULL
|| !mddev->ready) {
@@ -284,7 +285,10 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
sectors = bio_sectors(bio);
mddev->pers->make_request(mddev, bio);
- generic_start_io_acct(rw, sectors, &mddev->gendisk->part0);
+ cpu = part_stat_lock();
+ part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
+ part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
+ part_stat_unlock();
if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
wake_up(&mddev->sb_wait);
--
2.34.1