From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Stuart Foster <smf.linux@ntlworld.com>,
linux-mm@kvack.org, bugzilla-daemon@bugzilla.kernel.org,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [Bug 42578] Kernel crash "Out of memory error by X" when using NTFS file system on external USB Hard drive
Date: Tue, 14 Feb 2012 12:37:12 -0800 [thread overview]
Message-ID: <20120214123712.77aa54ce.akpm@linux-foundation.org> (raw)
In-Reply-To: <20120214130955.GM17917@csn.ul.ie>
On Tue, 14 Feb 2012 13:09:55 +0000
Mel Gorman <mel@csn.ul.ie> wrote:
> Stuart Foster reported on https://bugzilla.kernel.org/show_bug.cgi?id=42578
> that copying large amounts of data from NTFS caused an OOM kill on 32-bit
> X86 with 16G of memory. Andrew Morton correctly identified that the problem
> was NTFS was using 512 blocks meaning each page had 8 buffer_heads in low
> memory pinning it.
>
> In the past, direct reclaim used to scan highmem even if the allocating
> process did not specify __GFP_HIGHMEM but not any more. kswapd no longer
> will reclaim from zones that are above the high watermark. The intention
> in both cases was to minimise unnecessary reclaim. The downside is on
> machines with large amounts of highmem that lowmem can be fully consumed
> by buffer_heads with nothing trying to free them.
>
> The following patch is based on a suggestion by Andrew Morton to extend
> the buffer_heads_over_limit case to force kswapd and direct reclaim to
> scan the highmem zone regardless of the allocation request or
> watermarks.
Seems reasonable, thanks.
I wonder if we really needed to change balance_pdgat(). The smaller we
can make profile of the special-case-hack the better. Perhaps poking
it into direct reclaim was sufficient?
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next prev parent reply other threads:[~2012-02-14 20:37 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 ` [Bug 42578] Kernel crash "Out of memory error by X" when using NTFS file system on external USB Hard drive Andrew Morton
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 [this message]
2012-02-15 13:57 ` Mel Gorman
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