From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>, linux-mm@kvack.org
Cc: bugzilla-daemon@bugzilla.kernel.org,
Stuart Foster <smf.linux@ntlworld.com>
Subject: Re: [Bug 42578] Kernel crash "Out of memory error by X" when using NTFS file system on external USB Hard drive
Date: Thu, 19 Jan 2012 12:24:48 -0800 [thread overview]
Message-ID: <20120119122448.1cce6e76.akpm@linux-foundation.org> (raw)
In-Reply-To: <201201180922.q0I9MCYl032623@bugzilla.kernel.org>
(switched to email. Please respond via emailed reply-to-all, not via the
bugzilla web interface).
On Wed, 18 Jan 2012 09:22:12 GMT
bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=42578
Stuart has an 8GB x86_32 machine. It has large amounts of NTFS
pagecache in highmem. NTFS is using 512-byte buffer_heads. All of the
machine's lowmem is being consumed by struct buffer_heads which are
attached to the highmem pagecache and the machine is dead in the water,
getting a storm of ooms.
A regression, I think. A box-killing one on a pretty simple workload
on a not uncommon machine.
We used to handle this by scanning highmem even when there was plenty
of free highmem and the request is for a lowmmem pages. We have made a
few changes in this area and I guess that's what broke it.
I think a suitable fix here would be to extend the
buffer_heads_over_limit special-case. If buffer_heads_over_limit is
true, both direct-reclaimers and kswapd should scan the highmem zone
regardless of incoming gfp_mask and regardless of the highmem free
pages count.
In this mode, we only scan the file lru. We should perform writeback
as well, because the buffer_heads might be dirty.
[aside: If all of a page's buffer_heads are dirty we can in fact
reclaim them and mark the entire page dirty. If some of the
buffer_heads are dirty and the others are uptodate we can even reclaim
them in this case, and mark the entire page dirty, causing extra I/O
later. But try_to_release_page() doesn't do these things.]
I think it is was always wrong that we only strip buffer_heads when
moving pages to the inactive list. What happens if those 600MB of
buffer_heads are all attached to inactive pages?
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next parent reply other threads:[~2012-01-19 20:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-42578-27@https.bugzilla.kernel.org/>
[not found] ` <201201180922.q0I9MCYl032623@bugzilla.kernel.org>
2012-01-19 20:24 ` Andrew Morton [this message]
2012-02-10 16:37 ` Mel Gorman
2012-02-10 17:01 ` Rik van Riel
2012-02-14 12:17 ` Mel Gorman
2012-02-11 21:28 ` Stuart Foster
2012-02-14 13:09 ` Mel Gorman
2012-02-14 20:00 ` Christoph Lameter
2012-02-14 20:34 ` Andrew Morton
2012-02-14 20:42 ` Christoph Lameter
2012-02-14 20:37 ` Andrew Morton
2012-02-15 13:57 ` Mel Gorman
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