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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@osdl.org>,
	marcelo.tosatti@cyclades.com, andrea@suse.de,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][5/?] count writeback pages in nr_scanned
Date: Thu, 06 Jan 2005 14:50:15 +1100	[thread overview]
Message-ID: <41DCB577.9000205@yahoo.com.au> (raw)
In-Reply-To: <Pine.LNX.4.61.0501052240250.11550@chimarrao.boston.redhat.com>

Rik van Riel wrote:
> On Wed, 5 Jan 2005, Andrew Morton wrote:
> 
>> Rik van Riel <riel@redhat.com> wrote:
> 
> 
>>> 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
>>
>>
>> You must have a wild number of requests configured in the queue.  Is 
>> this CFQ?
> 
> 
> Yes, it is with CFQ.  Around 650MB of lowmem is in writeback
> stage, which is over 99% of the active and inactive lowmem
> pages...
> 
>> I've done testing with "all of memory under writeback" before and it 
>> went OK.  It's certainly a design objective to handle this well.  But 
>> that testing was before we broke it.
> 
> 
> I suspect something might still be broken.  It may take a few
> days of continuous testing to trigger the bug, though ...
> 

It is possible to be those blk_congestion_wait paths, because
the queue simply won't be congested. So doing io_schedule_timeout
might help.

I wonder if reducing the size of the write queue in CFQ would help
too? IIRC, it only really wants a huge read queue.

  reply	other threads:[~2005-01-06  3:50 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-03 17:25 [PATCH][5/?] count writeback pages in nr_scanned Rik van Riel
2005-01-05 10:08 ` Andrew Morton
2005-01-05 18:06   ` Andrea Arcangeli
2005-01-05 18:50     ` Rik van Riel
2005-01-05 17:49       ` Marcelo Tosatti
2005-01-05 21:44         ` Andrew Morton
2005-01-05 20:32           ` Marcelo Tosatti
2005-01-05 23:51             ` Nick Piggin
2005-01-06  1:27               ` Rik van Riel
2005-01-06  1:33                 ` Nick Piggin
2005-01-06  1:37                   ` Andrew Morton
2005-01-06  1:40                     ` Nick Piggin
2005-01-06  1:52                       ` Andrea Arcangeli
2005-01-06  1:36                 ` Andrew Morton
2005-01-06  3:42                   ` Rik van Riel
2005-01-06  3:50                     ` Nick Piggin [this message]
2005-01-06  4:26                       ` Andrew Morton
2005-01-06  4:35                         ` Nick Piggin
2005-01-06  4:47                           ` Andrew Morton
2005-01-06  4:55                             ` Nick Piggin
2005-01-06  5:03                               ` Andrea Arcangeli
2005-01-06  8:06                               ` Jens Axboe
2005-01-06  8:16                                 ` memory barrier in ll_rw_blk.c (was Re: [PATCH][5/?] count writeback pages in nr_scanned) Nick Piggin
2005-01-06  8:32                                   ` Jens Axboe
2005-01-06  8:53                                     ` Nick Piggin
2005-01-06 12:00                                       ` Jens Axboe
2005-01-06  4:59                             ` [PATCH][5/?] count writeback pages in nr_scanned Andrea Arcangeli
2005-01-06  5:05                               ` Andrew Morton
2005-01-06  5:17                                 ` Andrea Arcangeli
2005-01-06  5:19                                   ` Nick Piggin
2005-01-06  5:25                                     ` Andrea Arcangeli
2005-01-06  5:36                                       ` Nick Piggin
2005-01-06  5:44                                         ` Nick Piggin
2005-01-06  5:37                                       ` Andrew Morton
2005-01-06  5:59                                         ` Andrea Arcangeli
2005-01-06 13:28                                         ` Rik van Riel
2005-01-06  5:32                                     ` Andrew Morton
2005-01-06  5:46                                       ` Andrea Arcangeli
2005-01-06  5:59                                         ` Andrew Morton
2005-01-06  6:16                                           ` Andrea Arcangeli
2005-01-06  5:06                               ` Nick Piggin
2005-01-06  5:21                                 ` Andrea Arcangeli
2005-01-05 23:26 ` Andrew Morton

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