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From: Arjan van de Ven <arjan@infradead.org>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, agk@redhat.com, mbroz@redhat.com,
	chris@arachsys.com
Subject: Re: [PATCH 2/3] Fix fsync livelock
Date: Sun, 5 Oct 2008 15:33:06 -0700	[thread overview]
Message-ID: <20081005153306.7e644c9f@infradead.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0810051814060.23248@hs20-bc2-1.build.redhat.com>

On Sun, 5 Oct 2008 18:14:50 -0400 (EDT)
Mikulas Patocka <mpatocka@redhat.com> wrote:

> Fix starvation in memory management.
> 
> The bug happens when one process is doing sequential buffered writes
> to a block device (or file) and another process is attempting to
> execute sync(), fsync() or direct-IO on that device (or file). This
> syncing process will wait indefinitelly, until the first writing
> process finishes.
> 
> For example, run these two commands:
> dd if=/dev/zero of=/dev/sda1 bs=65536 &
> dd if=/dev/sda1 of=/dev/null bs=4096 count=1 iflag=direct
> 
> The bug is caused by sequential walking of address space in
> write_cache_pages and wait_on_page_writeback_range: if some other
> process is constantly making dirty and writeback pages while these
> functions run, the functions will wait on every new page, resulting in
> indefinite wait.

are you sure?
isn't the right fix to just walk the file pages only once?

  reply	other threads:[~2008-10-05 22:33 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20080911101616.GA24064@agk.fab.redhat.com>
2008-09-22 21:10 ` [PATCH] Memory management livelock Mikulas Patocka
2008-09-23  0:48   ` Andrew Morton
2008-09-23 22:34   ` Mikulas Patocka
2008-09-23 22:49     ` Andrew Morton
2008-09-23 23:11       ` Mikulas Patocka
2008-09-23 23:46         ` Andrew Morton
2008-09-24 18:50           ` Mikulas Patocka
2008-09-24 18:51           ` [PATCH 1/3] " Mikulas Patocka
2008-09-24 18:52           ` [PATCH 2/3] " Mikulas Patocka
2008-10-02  5:54             ` Andrew Morton
2008-10-05 22:11               ` RFC: one-bit mutexes (was: Re: [PATCH 2/3] Memory management livelock) Mikulas Patocka
2008-10-11 12:06                 ` Nick Piggin
2008-10-20 20:14                   ` Mikulas Patocka
2008-10-21  1:51                     ` Nick Piggin
2008-10-05 22:14               ` [PATCH 1/3] bit mutexes Mikulas Patocka
2008-10-05 22:14               ` [PATCH 2/3] Fix fsync livelock Mikulas Patocka
2008-10-05 22:33                 ` Arjan van de Ven [this message]
2008-10-05 23:02                   ` Mikulas Patocka
2008-10-05 23:07                     ` Arjan van de Ven
2008-10-05 23:18                       ` Mikulas Patocka
2008-10-05 23:28                         ` Arjan van de Ven
2008-10-06  0:01                           ` Mikulas Patocka
2008-10-06  0:30                             ` Arjan van de Ven
2008-10-06  3:30                               ` Mikulas Patocka
2008-10-06  4:20                                 ` Arjan van de Ven
2008-10-06 13:00                                   ` Mikulas Patocka
2008-10-06 13:50                                     ` Arjan van de Ven
2008-10-06 20:44                                       ` Mikulas Patocka
2008-10-08 10:56                               ` Pavel Machek
2008-10-06  2:51                             ` Dave Chinner
2008-10-05 22:16               ` [PATCH 3/3] Fix fsync-vs-write misbehavior Mikulas Patocka
2008-10-09  1:12               ` [PATCH] documentation: explain memory barriers Randy Dunlap
2008-10-09  1:17                 ` Chris Snook
2008-10-09  1:31                   ` Andrew Morton
2008-10-09  5:51                     ` Chris Snook
2008-10-09  9:58                       ` Ben Hutchings
2008-10-09 21:27                         ` Nick Piggin
2008-10-09 17:29                       ` Nick Piggin
2008-10-09  1:50                 ` Valdis.Kletnieks
2008-10-09 17:35                   ` Nick Piggin
2008-10-09  6:52                     ` Valdis.Kletnieks
2008-09-24 18:53           ` [PATCH 3/3] Memory management livelock Mikulas Patocka
2008-10-03  2:32       ` [PATCH] " Nick Piggin
2008-10-03  2:40         ` Andrew Morton
2008-10-03  2:59           ` Nick Piggin
2008-10-03  3:14             ` Andrew Morton
2008-10-03  3:47               ` Nick Piggin
2008-10-03  3:56                 ` Andrew Morton
2008-10-03  4:07                   ` Nick Piggin
2008-10-03  4:17                     ` Andrew Morton
2008-10-03  4:29                       ` Nick Piggin
2008-10-03 11:43                   ` Mikulas Patocka
2008-10-03 12:27                     ` Nick Piggin
2008-10-03 13:53                       ` Mikulas Patocka
2008-10-03  2:54         ` Nick Piggin
2008-10-03 11:26           ` Mikulas Patocka
2008-10-03 12:31             ` Nick Piggin
2008-10-03 13:50               ` Mikulas Patocka
2008-10-03 14:50                 ` Alasdair G Kergon
2008-10-03 14:36               ` Alasdair G Kergon
2008-10-03 15:52           ` application syncing options (was Re: [PATCH] Memory management livelock) david
2008-10-06  0:04             ` Mikulas Patocka
2008-10-06  0:19               ` david
2008-10-06  3:42                 ` Mikulas Patocka
2008-10-07  3:37                   ` david
2008-10-07 15:44                     ` Mikulas Patocka
2008-10-07 17:16                       ` david

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