From: Wu Fengguang <fengguang.wu@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@linux.vnet.ibm.com>, Mel Gorman <mel@csn.ul.ie>,
Dave Chinner <david@fromorbit.com>,
Itaru Kitayama <kitayama@cl.bb4u.ne.jp>,
Minchan Kim <minchan.kim@gmail.com>,
Linux Memory Management List <linux-mm@kvack.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/6] writeback: refill b_io iff empty
Date: Fri, 6 May 2011 00:47:12 +0800 [thread overview]
Message-ID: <20110505164712.GA2548@localhost> (raw)
In-Reply-To: <20110505163708.GN5323@quack.suse.cz>
On Fri, May 06, 2011 at 12:37:08AM +0800, Jan Kara wrote:
> On Wed 04-05-11 15:39:31, Wu Fengguang wrote:
> > To help understand the behavior change, I wrote the writeback_queue_io
> > trace event, and found very different patterns between
> > - vanilla kernel
> > - this patchset plus the sync livelock fixes
> >
> > Basically the vanilla kernel each time pulls a random number of inodes
> > from b_dirty, while the patched kernel tends to pull a fixed number of
> > inodes (enqueue=1031) from b_dirty. The new behavior is very interesting...
> This regularity is really strange. Did you have a chance to look more into
> it? I find it highly unlikely that there would be exactly 1031 dirty inodes
> in b_dirty list every time you call move_expired_inodes()...
Yeah that's the weird point. The other things I noticed are more
regular "flusher - dd - flusher - dd - ..." writeout patterns after
the patches. In vanilla kernel it behaves more randomly and there are
many balance_dirty_pages() IOs from tar.
I'll try to collect more traces in ext4 tomorrow. Sorry it's too late
for me now.
Thanks,
Fengguang
WARNING: multiple messages have this Message-ID (diff)
From: Wu Fengguang <fengguang.wu@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@linux.vnet.ibm.com>, Mel Gorman <mel@csn.ul.ie>,
Dave Chinner <david@fromorbit.com>,
Itaru Kitayama <kitayama@cl.bb4u.ne.jp>,
Minchan Kim <minchan.kim@gmail.com>,
Linux Memory Management List <linux-mm@kvack.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/6] writeback: refill b_io iff empty
Date: Fri, 6 May 2011 00:47:12 +0800 [thread overview]
Message-ID: <20110505164712.GA2548@localhost> (raw)
In-Reply-To: <20110505163708.GN5323@quack.suse.cz>
On Fri, May 06, 2011 at 12:37:08AM +0800, Jan Kara wrote:
> On Wed 04-05-11 15:39:31, Wu Fengguang wrote:
> > To help understand the behavior change, I wrote the writeback_queue_io
> > trace event, and found very different patterns between
> > - vanilla kernel
> > - this patchset plus the sync livelock fixes
> >
> > Basically the vanilla kernel each time pulls a random number of inodes
> > from b_dirty, while the patched kernel tends to pull a fixed number of
> > inodes (enqueue=1031) from b_dirty. The new behavior is very interesting...
> This regularity is really strange. Did you have a chance to look more into
> it? I find it highly unlikely that there would be exactly 1031 dirty inodes
> in b_dirty list every time you call move_expired_inodes()...
Yeah that's the weird point. The other things I noticed are more
regular "flusher - dd - flusher - dd - ..." writeout patterns after
the patches. In vanilla kernel it behaves more randomly and there are
many balance_dirty_pages() IOs from tar.
I'll try to collect more traces in ext4 tomorrow. Sorry it's too late
for me now.
Thanks,
Fengguang
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next prev parent reply other threads:[~2011-05-05 16:47 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-20 8:03 [PATCH 0/6] writeback: moving expire targets for background/kupdate works v2 Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` [PATCH 1/6] writeback: pass writeback_control down to move_expired_inodes() Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-05-04 11:04 ` Christoph Hellwig
2011-05-04 11:04 ` Christoph Hellwig
2011-05-04 11:13 ` Wu Fengguang
2011-05-04 11:13 ` Wu Fengguang
2011-04-20 8:03 ` [PATCH 2/6] writeback: introduce writeback_control.inodes_cleaned Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-05-04 11:05 ` Christoph Hellwig
2011-05-04 11:05 ` Christoph Hellwig
2011-05-04 11:11 ` Wu Fengguang
2011-05-04 11:11 ` Wu Fengguang
2011-05-04 11:16 ` Christoph Hellwig
2011-05-04 11:16 ` Christoph Hellwig
2011-05-04 11:32 ` Wu Fengguang
2011-05-04 11:32 ` Wu Fengguang
2011-04-20 8:03 ` [PATCH 3/6] writeback: try more writeback as long as something was written Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` [PATCH 4/6] writeback: the kupdate expire timestamp should be a moving target Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` [PATCH 5/6] writeback: sync expired inodes first in background writeback Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 23:40 ` Andrew Morton
2011-04-20 23:40 ` Andrew Morton
2011-04-20 23:40 ` Andrew Morton
2011-04-21 1:14 ` Wu Fengguang
2011-04-21 1:14 ` Wu Fengguang
2011-04-21 1:21 ` Wu Fengguang
2011-04-21 1:21 ` Wu Fengguang
2011-04-24 3:15 ` Wu Fengguang
2011-04-24 3:15 ` Wu Fengguang
2011-04-26 12:17 ` Jan Kara
2011-04-26 12:17 ` Jan Kara
2011-04-26 13:51 ` Wu Fengguang
2011-04-26 13:51 ` Wu Fengguang
2011-04-26 13:59 ` Wu Fengguang
2011-04-26 13:59 ` Wu Fengguang
2011-04-26 14:05 ` Wu Fengguang
2011-04-26 14:05 ` Wu Fengguang
2011-04-27 11:15 ` Wu Fengguang
2011-04-27 11:15 ` Wu Fengguang
2011-04-20 8:03 ` [PATCH 6/6] writeback: refill b_io iff empty Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-04-20 8:03 ` Wu Fengguang
2011-05-04 7:39 ` Wu Fengguang
2011-05-05 16:37 ` Jan Kara
2011-05-05 16:37 ` Jan Kara
2011-05-05 16:47 ` Wu Fengguang [this message]
2011-05-05 16:47 ` Wu Fengguang
2011-05-06 5:29 ` Wu Fengguang
2011-05-06 5:29 ` Wu Fengguang
2011-05-06 8:42 ` [RFC][PATCH] writeback: limit number of moved inodes in queue_io() Wu Fengguang
2011-05-06 8:42 ` Wu Fengguang
2011-05-06 10:06 ` [RFC][PATCH v2] " Wu Fengguang
2011-05-06 10:06 ` Wu Fengguang
2011-05-06 23:06 ` Dave Chinner
2011-05-06 23:06 ` Dave Chinner
2011-05-06 14:21 ` [PATCH 6/6] writeback: refill b_io iff empty Jan Kara
2011-05-06 14:21 ` Jan Kara
2011-05-10 4:31 ` Wu Fengguang
2011-05-10 4:53 ` Dave Chinner
2011-05-10 4:53 ` Dave Chinner
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