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: Sat, 20 Apr 2013 20:05:22 -0400 [thread overview]
Message-ID: <20130421000522.GA5054@thunk.org> (raw)
In-Reply-To: <20130412094731.GI11656@suse.de>
As an update to this thread, we brought up this issue at LSF/MM, and
there is a thought that we should be able to solve this problem by
having lock_buffer() check to see if the buffer is locked due to a
write being queued, to have the priority of the write bumped up in the
write queues to resolve the priority inversion. I believe Jeff Moyer
was going to look into this, if I remember correctly.
An alternate solution which I've been playing around adds buffer_head
flags so we can indicate that a buffer contains metadata and/or should
have I/O submitted with the REQ_PRIO flag set.
Adding a buffer_head flag for at least BH_Meta is probably a good
thing, since that way the blktrace will be properly annotated.
Whether we should keep the BH_Prio flag or rely on lock_buffer()
automatically raising the priority is, my feeling is that if
lock_buffer() can do the right thing, we should probably do it via
lock_buffer(). I have a feeling this might be decidedly non-trivial,
though, so perhaps we should just doing via BH flags?
- 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: Sat, 20 Apr 2013 20:05:22 -0400 [thread overview]
Message-ID: <20130421000522.GA5054@thunk.org> (raw)
In-Reply-To: <20130412094731.GI11656@suse.de>
As an update to this thread, we brought up this issue at LSF/MM, and
there is a thought that we should be able to solve this problem by
having lock_buffer() check to see if the buffer is locked due to a
write being queued, to have the priority of the write bumped up in the
write queues to resolve the priority inversion. I believe Jeff Moyer
was going to look into this, if I remember correctly.
An alternate solution which I've been playing around adds buffer_head
flags so we can indicate that a buffer contains metadata and/or should
have I/O submitted with the REQ_PRIO flag set.
Adding a buffer_head flag for at least BH_Meta is probably a good
thing, since that way the blktrace will be properly annotated.
Whether we should keep the BH_Prio flag or rely on lock_buffer()
automatically raising the priority is, my feeling is that if
lock_buffer() can do the right thing, we should probably do it via
lock_buffer(). I have a feeling this might be decidedly non-trivial,
though, so perhaps we should just doing via BH flags?
- Ted
next prev parent reply other threads:[~2013-04-21 0:05 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 [this message]
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
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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