From: Wu Fengguang <fengguang.wu@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
"Tang, Feng" <feng.tang@intel.com>
Subject: Re: [PATCH 0/7] writeback: avoid touching dirtied_when on blocked inodes
Date: Sat, 22 Oct 2011 15:07:35 +0800 [thread overview]
Message-ID: <20111022070735.GA32340@localhost> (raw)
In-Reply-To: <20111022065926.GA31074@localhost>
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On Sat, Oct 22, 2011 at 02:59:26PM +0800, Wu Fengguang wrote:
> > In general it looks better we first root case the "decreasing wrote
> > pages by writeback_single_inode() over time" problem before looking
> > into further steps..
>
> The problem shows up in many of the regression cases. For example,
> the thresh=1G/ext4-100dd case with patches 1-4 applied will not only
> see nr_writeback occasionally dropped low (bdi_dirty_state-8:0.png),
> but also see repeated pattern of nr_wrote by writeback_single_inode()
> slowly decreasing to 0 during some period of dozens of seconds
> (writeback_single_inode.png).
Another example is the thresh=1G/xfs-100dd case with patches 1-4 and
Jan's requeue_io_wait-on-I_SYNC patch. The writeback_single_inode.png
graph shows steadily decreasing wrote pages in some period of 400
seconds. It's accompanied by decrease of nr_writeback, IO size and
impacts write bandwidth a lot.
Thanks,
Fengguang
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next prev parent reply other threads:[~2011-10-22 7:07 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-20 15:22 [PATCH 0/7] writeback: avoid touching dirtied_when on blocked inodes Wu Fengguang
2011-10-20 15:22 ` [PATCH 1/7] writeback: introduce queue b_more_io_wait Wu Fengguang
2011-10-20 23:23 ` Jan Kara
2011-10-20 15:22 ` [PATCH 2/7] writeback: avoid redirtying when ->write_inode failed to clear I_DIRTY Wu Fengguang
2011-10-20 23:24 ` Jan Kara
2011-10-20 15:22 ` [PATCH 3/7] writeback: update wb->last_active on written pages/inodes Wu Fengguang
2011-10-20 15:22 ` [PATCH 4/7] writeback: Retry kupdate work early if we need to retry some inode writeback Wu Fengguang
2011-10-20 15:22 ` [PATCH 5/7] writeback: requeue_io_wait() on pages_skipped inode Wu Fengguang
2011-10-20 23:25 ` Jan Kara
2011-10-20 15:22 ` [PATCH 6/7] writeback: requeue_io_wait() on blocked inode Wu Fengguang
2011-10-20 23:31 ` Jan Kara
2011-10-20 15:22 ` [PATCH 7/7] writeback: requeue_io_wait() when failed to grab superblock Wu Fengguang
2011-10-20 23:25 ` Jan Kara
2011-10-20 23:21 ` [PATCH 0/7] writeback: avoid touching dirtied_when on blocked inodes Jan Kara
2011-10-21 10:40 ` Wu Fengguang
2011-10-21 19:54 ` Jan Kara
2011-10-22 3:11 ` Wu Fengguang
2011-10-22 5:38 ` Wu Fengguang
2011-10-22 6:59 ` Wu Fengguang
2011-10-22 7:07 ` Wu Fengguang [this message]
2011-10-22 7:46 ` Wu Fengguang
2011-10-22 4:46 ` Wu Fengguang
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