From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: kosaki.motohiro@jp.fujitsu.com, axboe@kernel.dk,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blk: fix a wrong accounting of hd_struct->in_flight
Date: Thu, 14 Oct 2010 15:07:19 +0900 (JST) [thread overview]
Message-ID: <20101014150742.F9EC.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <4CB40281.1020403@jp.fujitsu.com>
Hello,
> From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>
> /proc/diskstats would display a strange output as follows.
>
> $ cat /proc/diskstats |grep sda
> 8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
> 8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
> ~~~~~~~~~~
> 8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
> 8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92
> 8 4 sda4 4 0 8 0 0 0 0 0 0 0 0
> 8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137
Hm, this is very nasty and crap.
> @@ -1268,7 +1270,17 @@ static int __make_request(struct request
> * not touch req->buffer either...
> */
> req->buffer = bio_data(bio);
> + src_part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
> req->__sector = bio->bi_sector;
> + dst_part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
I think this is wrong. disk_map_sector_rcu() require
rcu read lock held (see function comment). all other call site take
part_stat_lock() before disk_map_sector_rcu() call.
next prev parent reply other threads:[~2010-10-14 6:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-12 6:38 Yasuaki Ishimatsu
2010-10-12 8:19 ` Jens Axboe
2010-10-14 12:48 ` [PATCH v2] " Yasuaki Ishimatsu
2010-10-14 12:55 ` Jens Axboe
2010-10-15 8:39 ` [PATCH v3] " Yasuaki Ishimatsu
2010-10-15 10:04 ` Jens Axboe
2010-10-18 8:28 ` [PATCH v4] " Yasuaki Ishimatsu
2010-10-18 8:34 ` Jens Axboe
2010-10-18 12:19 ` [PATCH v5] " Yasuaki Ishimatsu
2010-10-18 12:21 ` Jens Axboe
2010-10-19 2:22 ` Yasuaki Ishimatsu
2010-10-19 10:02 ` Jens Axboe
2010-10-14 6:07 ` KOSAKI Motohiro [this message]
2010-10-14 12:44 ` [PATCH] " Jens Axboe
2010-10-14 23:30 ` Paul E. McKenney
2010-10-15 7:30 ` Jens Axboe
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