Date: Tue, 14 Aug 2007 08:29:20 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
To: Peter Zijlstra <peterz@infradead.org>
cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 0/3] Recursive reclaim (on __PF_MEMALLOC)
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References: <20070814142103.204771292@sgi.com> <1187102203.6114.2.camel@twins>
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On Tue, 14 Aug 2007, Peter Zijlstra wrote:

> On Tue, 2007-08-14 at 07:21 -0700, Christoph Lameter wrote:
> > The following patchset implements recursive reclaim. Recursive reclaim
> > is necessary if we run out of memory in the writeout patch from reclaim.
> > 
> > This is f.e. important for stacked filesystems or anything that does
> > complicated processing in the writeout path.
> > 
> > Recursive reclaim works because it limits itself to only reclaim pages
> > that do not require writeout. It will only remove clean pages from the LRU.
> > The dirty throttling of the VM during regular reclaim insures that the amount
> > of dirty pages is limited. 
> 
> No it doesn't. All memory can be tied up by anonymous pages - who are
> dirty by definition and are not clamped by the dirty limit.

Ok but that could be addressed by making sure that a certain portion of 
memory is reserved for clean file backed pages.

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