From: Christoph Lameter <clameter@sgi.com>
To: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, dkegel@google.com,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
David Miller <davem@davemloft.net>, Nick Piggin <npiggin@suse.de>
Subject: Re: [RFC 0/7] Postphone reclaim laundry to write at high water marks
Date: Tue, 21 Aug 2007 13:59:24 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0708211355430.3082@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <46CB01B7.3050201@redhat.com>
On Tue, 21 Aug 2007, Rik van Riel wrote:
> Christoph Lameter wrote:
>
> > 1. First reclaiming non dirty pages. Dirty pages are deferred until reclaim
> > has reestablished the high marks. Then all the dirty pages (the laundry)
> > is written out.
>
> That sounds like a horrendously bad idea. While one process
> is busy freeing all the non dirty pages, other processes can
> allocate those pages, leaving you with no memory to free up
> the dirty pages!
What is preventing that from occurring right now? If the dirty pags are
aligned in the right way you can have the exact same situation.
> Also, writing out all the dirty pages at once seems like it
> could hurt latency quite badly, especially on large systems.
We only write back the dirty pages that we are about to reclaim not all of
them. The bigger batching occurs if we go through multiple priorities.
Plus writeback in the sync reclaim case is stopped if the device becomes
contended anyways.
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next prev parent reply other threads:[~2007-08-21 20:59 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-20 21:50 Christoph Lameter
2007-08-20 21:50 ` [RFC 1/7] release_lru_pages(): Generic release of pages to the LRU Christoph Lameter
2007-08-21 14:52 ` Mel Gorman
2007-08-21 20:51 ` Christoph Lameter
2007-08-20 21:50 ` [RFC 2/7] Move checks from pageout() to shrink_page_list Christoph Lameter
2007-08-20 21:50 ` [RFC 3/7] shrink_page_list: Support isolating dirty pages on laundry list Christoph Lameter
2007-08-21 15:04 ` Mel Gorman
2007-08-21 20:53 ` Christoph Lameter
2007-08-20 21:50 ` [RFC 4/7] Pass laundry through shrink_inactive_list() and shrink_zone() Christoph Lameter
2007-08-20 21:50 ` [RFC 5/7] Laundry handling for direct reclaim Christoph Lameter
2007-08-21 15:06 ` Mel Gorman
2007-08-21 20:55 ` Christoph Lameter
2007-08-21 15:19 ` Mel Gorman
2007-08-21 21:00 ` Christoph Lameter
2007-08-20 21:50 ` [RFC 6/7] kswapd: Do laundry after reclaim Christoph Lameter
2007-08-20 21:50 ` [RFC 7/7] Switch of PF_MEMALLOC during writeout Christoph Lameter
2007-08-20 23:08 ` Andi Kleen
2007-08-20 23:19 ` Christoph Lameter
2007-08-21 1:13 ` Andi Kleen
2007-08-21 10:36 ` [RFC 0/7] Postphone reclaim laundry to write at high water marks Peter Zijlstra
2007-08-21 20:48 ` Christoph Lameter
2007-08-21 21:13 ` Peter Zijlstra
2007-08-21 21:29 ` Christoph Lameter
2007-08-21 21:43 ` Rik van Riel
2007-08-21 22:32 ` Christoph Lameter
2007-08-23 12:05 ` Andrea Arcangeli
2007-08-23 20:23 ` Christoph Lameter
2007-08-21 22:09 ` Peter Zijlstra
2007-08-21 22:43 ` Christoph Lameter
2007-08-22 7:02 ` Peter Zijlstra
2007-08-22 19:04 ` Christoph Lameter
2007-08-22 20:03 ` Peter Zijlstra
2007-08-22 20:16 ` Christoph Lameter
2007-08-23 7:39 ` Peter Zijlstra
2007-08-26 4:52 ` Rik van Riel
2007-08-23 12:16 ` Andrea Arcangeli
2007-08-22 7:45 ` Ingo Molnar
2007-08-22 19:19 ` Christoph Lameter
2007-08-23 12:08 ` Andrea Arcangeli
2007-08-23 12:59 ` Peter Zijlstra
2007-08-21 15:16 ` Rik van Riel
2007-08-21 20:59 ` Christoph Lameter [this message]
2007-08-21 21:14 ` Rik van Riel
2007-08-21 21:30 ` Christoph Lameter
2007-08-21 15:51 ` Dave McCracken
2007-08-21 21:03 ` Christoph Lameter
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