Date: Wed, 5 Jan 2005 20:27:22 -0500 (EST)
From: Rik van Riel <riel@redhat.com>
To: Nick Piggin <nickpiggin@yahoo.com.au>
cc: Marcelo Tosatti <marcelo.tosatti@cyclades.com>,
       Andrew Morton <akpm@osdl.org>, andrea@suse.de,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH][5/?] count writeback pages in nr_scanned
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On Thu, 6 Jan 2005, Nick Piggin wrote:

> I think what Andrea is worried about is that blk_congestion_wait is 
> fairly vague, and can be a source of instability in the scanning 
> implementation.

The recent OOM kill problem has been happening:
1) with cache pressure on lowmem only, due to a block device write
2) with no block congestion at all
3) with pretty much all pageable lowmme pages in writeback state

It appears the VM has trouble dealing with the situation where
there is no block congestion to wait on...

-- 
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan
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