From: Theodore Ts'o <tytso@mit.edu>
To: Mel Gorman <mgorman@suse.de>
Cc: Jan Kara <jack@suse.cz>,
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: Tue, 23 Apr 2013 11:50:19 -0400 [thread overview]
Message-ID: <20130423155019.GH31170@thunk.org> (raw)
In-Reply-To: <20130423153305.GB2108@suse.de>
On Tue, Apr 23, 2013 at 04:33:05PM +0100, Mel Gorman wrote:
> That's a pretty big drop but it gets bad again for the second worst stall --
> wait_on_page_bit as a result of generic_file_buffered_write.
>
> Vanilla kernel 1336064 ms stalled with 109 events
> Patched kernel 2338781 ms stalled with 164 events
Do you have the stack trace for this stall? I'm wondering if this is
caused by the waiting for stable pages in write_begin() , or something
else.
If it is blocking caused by stable page writeback that's interesting,
since it would imply that something in your workload is trying to
write to a page that has already been modified (i.e., appending to a
log file, or updating a database file). Does that make sense given
what your workload might be running?
- Ted
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WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: Mel Gorman <mgorman@suse.de>
Cc: Jan Kara <jack@suse.cz>,
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: Tue, 23 Apr 2013 11:50:19 -0400 [thread overview]
Message-ID: <20130423155019.GH31170@thunk.org> (raw)
In-Reply-To: <20130423153305.GB2108@suse.de>
On Tue, Apr 23, 2013 at 04:33:05PM +0100, Mel Gorman wrote:
> That's a pretty big drop but it gets bad again for the second worst stall --
> wait_on_page_bit as a result of generic_file_buffered_write.
>
> Vanilla kernel 1336064 ms stalled with 109 events
> Patched kernel 2338781 ms stalled with 164 events
Do you have the stack trace for this stall? I'm wondering if this is
caused by the waiting for stable pages in write_begin() , or something
else.
If it is blocking caused by stable page writeback that's interesting,
since it would imply that something in your workload is trying to
write to a page that has already been modified (i.e., appending to a
log file, or updating a database file). Does that make sense given
what your workload might be running?
- Ted
next prev parent reply other threads:[~2013-04-23 15:50 UTC|newest]
Thread overview: 105+ 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 14:27 ` Mel Gorman
2013-04-02 15:00 ` Jiri Slaby
2013-04-02 15:00 ` Jiri Slaby
2013-04-02 15:03 ` Zheng Liu
2013-04-02 15:03 ` Zheng Liu
2013-04-02 15:15 ` Mel Gorman
2013-04-02 15:15 ` Mel Gorman
2013-04-02 15:06 ` Theodore Ts'o
2013-04-02 15:06 ` Theodore Ts'o
2013-04-02 15:14 ` Theodore Ts'o
2013-04-02 15:14 ` Theodore Ts'o
2013-04-02 18:19 ` Theodore Ts'o
2013-04-02 18:19 ` Theodore Ts'o
2013-04-07 21:59 ` Frank Ch. Eigler
2013-04-07 21:59 ` Frank Ch. Eigler
2013-04-08 8:36 ` Mel Gorman
2013-04-08 8:36 ` Mel Gorman
2013-04-08 10:52 ` Frank Ch. Eigler
2013-04-08 10:52 ` Frank Ch. Eigler
2013-04-08 11:01 ` Theodore Ts'o
2013-04-08 11:01 ` Theodore Ts'o
2013-04-03 10:19 ` Mel Gorman
2013-04-03 10:19 ` Mel Gorman
2013-04-03 12:05 ` Theodore Ts'o
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 22:18 ` Jiri Slaby
2013-04-05 23:16 ` Theodore Ts'o
2013-04-05 23:16 ` Theodore Ts'o
2013-04-06 7:29 ` Jiri Slaby
2013-04-06 7:29 ` Jiri Slaby
2013-04-06 7:37 ` Jiri Slaby
2013-04-06 7:37 ` Jiri Slaby
2013-04-06 8:19 ` Jiri Slaby
2013-04-06 13:15 ` Theodore Ts'o
2013-04-06 13:15 ` Theodore Ts'o
2013-04-10 10:56 ` Mel Gorman
2013-04-10 10:56 ` Mel Gorman
2013-04-10 13:12 ` Theodore Ts'o
2013-04-10 13:12 ` Theodore Ts'o
2013-04-11 17:04 ` Mel Gorman
2013-04-11 17:04 ` Mel Gorman
2013-04-11 18:35 ` Theodore Ts'o
2013-04-11 18:35 ` Theodore Ts'o
2013-04-11 21:33 ` Jan Kara
2013-04-11 21:33 ` Jan Kara
2013-04-12 2:57 ` Theodore Ts'o
2013-04-12 2:57 ` Theodore Ts'o
2013-04-12 4:50 ` Dave Chinner
2013-04-12 4:50 ` Dave Chinner
2013-04-12 15:19 ` Theodore Ts'o
2013-04-12 15:19 ` Theodore Ts'o
2013-04-13 1:23 ` Dave Chinner
2013-04-13 1:23 ` Dave Chinner
2013-04-22 14:38 ` Mel Gorman
2013-04-22 14:38 ` Mel Gorman
2013-04-22 22:42 ` Jeff Moyer
2013-04-22 22:42 ` Jeff Moyer
2013-04-23 0:02 ` Theodore Ts'o
2013-04-23 0:02 ` Theodore Ts'o
2013-04-23 9:31 ` Jan Kara
2013-04-23 9:31 ` Jan Kara
2013-04-23 14:01 ` Mel Gorman
2013-04-23 14:01 ` Mel Gorman
2013-04-24 19:09 ` Jeff Moyer
2013-04-24 19:09 ` Jeff Moyer
2013-04-25 12:21 ` Mel Gorman
2013-04-25 12:21 ` Mel Gorman
2013-04-12 9:47 ` Mel Gorman
2013-04-12 9:47 ` Mel Gorman
2013-04-21 0:05 ` Theodore Ts'o
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 ` 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 ` Theodore Ts'o
2013-04-21 0:07 ` [PATCH 3/3] ext4: mark metadata blocks using bh flags Theodore Ts'o
2013-04-21 0:07 ` Theodore Ts'o
2013-04-21 6:09 ` Jiri Slaby
2013-04-21 6:09 ` Jiri Slaby
2013-04-21 6:09 ` Jiri Slaby
2013-04-21 19:55 ` Theodore Ts'o
2013-04-21 19:55 ` Theodore Ts'o
2013-04-21 19:55 ` Theodore Ts'o
2013-04-21 20:48 ` [PATCH 3/3 -v2] " Theodore Ts'o
2013-04-21 20:48 ` Theodore Ts'o
2013-04-21 20:48 ` Theodore Ts'o
2013-04-22 12:06 ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Zheng Liu
2013-04-22 12:06 ` Zheng Liu
2013-04-23 15:33 ` Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-23 15:33 ` Mel Gorman
2013-04-23 15:50 ` Theodore Ts'o [this message]
2013-04-23 15:50 ` Theodore Ts'o
2013-04-23 16:13 ` Mel Gorman
2013-04-23 16:13 ` Mel Gorman
2013-04-12 10:18 ` Tvrtko Ursulin
2013-04-12 10:18 ` Tvrtko Ursulin
2013-04-12 9:45 ` Mel Gorman
2013-04-12 9:45 ` Mel Gorman
2013-04-02 23:16 ` Theodore Ts'o
2013-04-02 23:16 ` Theodore Ts'o
2013-04-03 15:22 ` Mel Gorman
2013-04-03 15:22 ` Mel Gorman
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