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Date: Fri, 9 Oct 2009 17:47:59 +0200
From: Jan Kara <jack@suse.cz>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jan Kara <jack@suse.cz>, Wu Fengguang <fengguang.wu@intel.com>,
       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>, Li Shaohua <shaohua.li@intel.com>,
       Myklebust Trond <Trond.Myklebust@netapp.com>,
       "jens.axboe@oracle.com" <jens.axboe@oracle.com>,
       Nick Piggin <npiggin@suse.de>, linux-fsdevel@vger.kernel.org,
       Richard Kennedy <richard@rsk.demon.co.uk>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 01/45] writeback: reduce calls to global_page_state in
	balance_dirty_pages()
Message-ID: <20091009154759.GJ7654@duck.suse.cz>
References: <20091007073818.318088777@intel.com> <20091007074901.251116016@intel.com> <20091009151230.GF7654@duck.suse.cz> <1255101512.8802.65.camel@laptop>
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On Fri 09-10-09 17:18:32, Peter Zijlstra wrote:
> On Fri, 2009-10-09 at 17:12 +0200, Jan Kara wrote:
> >   Ugh, but this is not equivalent! We would block the writer on some BDI
> > without any dirty data if we are over global dirty limit. That didn't
> > happen before.
> 
> It should have, we should throttle everything calling
> balance_dirty_pages() when we're over the total limit.
  OK :) I agree it's reasonable. But Wu, please note this in the
changelog because it might be a substantial change for some loads.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR