From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wu Fengguang <fengguang.wu@intel.com>
Subject: Re: [PATCH 09/45] writeback: quit on wrap for .range_cyclic
	(pohmelfs)
Date: Wed, 7 Oct 2009 22:23:30 +0800
Message-ID: <20091007142330.GA8622@localhost>
References: <20091007073818.318088777@intel.com> <20091007074902.268825252@intel.com> <20091007123211.GA29371@ioremap.net>
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Cc: Andrew Morton <akpm@linux-foundation.org>,
	Theodore Tso <tytso@mit.edu>,
	Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <david@fromorbit.com>,
	Chris Mason <chris.mason@oracle.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	"Li, Shaohua" <shaohua.li@intel.com>,
	Myklebust Trond <Trond.Myklebust@netapp.com>,
	"jens.axboe@oracle.com" <jens.axboe@oracle.com>,
	Jan Kara <jack@suse.cz>, Nick Piggin <npiggin@suse.de>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
To: Evgeniy Polyakov <zbr@ioremap.net>
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On Wed, Oct 07, 2009 at 08:32:11PM +0800, Evgeniy Polyakov wrote:
> Hi.
> 
> On Wed, Oct 07, 2009 at 03:38:27PM +0800, Wu Fengguang (fengguang.wu@intel.com) wrote:
> > Convert wbc.range_cyclic to new behavior: when past EOF, abort writeback
> > of the inode, which instructs writeback_single_inode() to delay it for 
> > a while if necessary.
> > 
> > It removes one inefficient .range_cyclic IO pattern when writeback_index
> > wraps:
> > 	submit [10000-10100], (wrap), submit [0-100]
> > In which the submitted pages may be consisted of two distant ranges.
> > 
> > It also prevents submitting pointless IO for busy overwriters.
> 
> I have no objections against this patchset, since I followed the
> upstream writeback behaviour and did not personally observe such wraps
> which would be otherwise handled in a single run.

OK, thanks!

Fengguang