From: Dave McCracken <dave.mccracken@oracle.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 0/7] Postphone reclaim laundry to write at high water marks
Date: Tue, 21 Aug 2007 10:51:35 -0500 [thread overview]
Message-ID: <200708211051.36569.dave.mccracken@oracle.com> (raw)
In-Reply-To: <20070820215040.937296148@sgi.com>
On Monday 20 August 2007, 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.
I don't buy it. What happens when there aren't enough clean pages in the
system to achieve the high water mark? I'm guessing we'd get a quick OOM (as
observed by Peter).
> 2. Reclaim is essentially complete during the writeout phase. So we remove
> PF_MEMALLOC and allow recursive reclaim if we still run into trouble
> during writeout.
You're assuming the system is static and won't allocate new pages behind your
back. We could be back to critically low memory before the write happens.
More broadly, we need to be proactive about getting dirty pages cleaned before
they consume the system. Deferring the write just makes it harder to keep
up.
Dave McCracken
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next prev parent reply other threads:[~2007-08-21 15:51 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
2007-08-21 21:14 ` Rik van Riel
2007-08-21 21:30 ` Christoph Lameter
2007-08-21 15:51 ` Dave McCracken [this message]
2007-08-21 21:03 ` Christoph Lameter
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