From: Theodore Ts'o <tytso@mit.edu>
To: Mel Gorman <mgorman@suse.de>
Cc: linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>
Subject: Re: Excessive stall times on ext4 in 3.9-rc2
Date: Wed, 10 Apr 2013 09:12:45 -0400 [thread overview]
Message-ID: <20130410131245.GC4862@thunk.org> (raw)
In-Reply-To: <20130410105608.GC1910@suse.de>
On Wed, Apr 10, 2013 at 11:56:08AM +0100, Mel Gorman wrote:
> During major activity there is likely to be "good" behaviour
> with stalls roughly every 30 seconds roughly corresponding to
> dirty_expire_centiseconds. As you'd expect, the flusher thread is stuck
> when this happens.
>
> 237 ? 00:00:00 flush-8:0
> [<ffffffff811a35b9>] sleep_on_buffer+0x9/0x10
> [<ffffffff811a35ee>] __lock_buffer+0x2e/0x30
> [<ffffffff8123a21f>] do_get_write_access+0x43f/0x4b0
If we're stalling on lock_buffer(), that implies that buffer was being
written, and for some reason it was taking a very long time to
complete.
It might be worthwhile to put a timestamp in struct dm_crypt_io, and
record the time when a particular I/O encryption/decryption is getting
queued to the kcryptd workqueues, and when they finally squirt out.
Something else that might be worth trying is to add WQ_HIGHPRI to the
workqueue flags and see if that makes a difference.
- Ted
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next prev parent reply other threads:[~2013-04-10 13:12 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-02 14:27 Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-02 15:00 ` Jiri Slaby
2013-04-02 15:03 ` Zheng Liu
2013-04-02 15:15 ` Mel Gorman
2013-04-02 15:06 ` Theodore Ts'o
2013-04-02 15:14 ` Theodore Ts'o
2013-04-02 18:19 ` Theodore Ts'o
2013-04-07 21:59 ` Frank Ch. Eigler
2013-04-08 8:36 ` Mel Gorman
2013-04-08 10:52 ` Frank Ch. Eigler
2013-04-08 11:01 ` Theodore Ts'o
2013-04-03 10:19 ` Mel Gorman
2013-04-03 12:05 ` Theodore Ts'o
2013-04-03 15:15 ` Mel Gorman
2013-04-05 22:18 ` Jiri Slaby
2013-04-05 23:16 ` Theodore Ts'o
2013-04-06 7:29 ` Jiri Slaby
2013-04-06 7:37 ` Jiri Slaby
2013-04-06 8:19 ` Jiri Slaby
2013-04-06 13:15 ` Theodore Ts'o
2013-04-10 10:56 ` Mel Gorman
2013-04-10 13:12 ` Theodore Ts'o [this message]
2013-04-11 17:04 ` Mel Gorman
2013-04-11 18:35 ` Theodore Ts'o
2013-04-11 21:33 ` Jan Kara
2013-04-12 2:57 ` Theodore Ts'o
2013-04-12 4:50 ` Dave Chinner
2013-04-12 15:19 ` Theodore Ts'o
2013-04-13 1:23 ` Dave Chinner
2013-04-22 14:38 ` Mel Gorman
2013-04-22 22:42 ` Jeff Moyer
2013-04-23 0:02 ` Theodore Ts'o
2013-04-23 9:31 ` Jan Kara
2013-04-23 14:01 ` Mel Gorman
2013-04-24 19:09 ` Jeff Moyer
2013-04-25 12:21 ` Mel Gorman
2013-04-12 9:47 ` Mel Gorman
2013-04-21 0:05 ` Theodore Ts'o
2013-04-21 0:07 ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Theodore Ts'o
2013-04-21 0:07 ` [PATCH 2/3] buffer: add BH_Prio and BH_Meta flags Theodore Ts'o
2013-04-21 0:07 ` [PATCH 3/3] ext4: mark metadata blocks using bh flags Theodore Ts'o
2013-04-21 6:09 ` Jiri Slaby
2013-04-21 19:55 ` Theodore Ts'o
2013-04-21 20:48 ` [PATCH 3/3 -v2] " Theodore Ts'o
2013-04-22 12:06 ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Zheng Liu
2013-04-23 15:33 ` Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-23 15:50 ` Theodore Ts'o
2013-04-23 16:13 ` Mel Gorman
2013-04-12 10:18 ` Tvrtko Ursulin
2013-04-12 9:45 ` Mel Gorman
2013-04-02 23:16 ` Theodore Ts'o
2013-04-03 15:22 ` Mel Gorman
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