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From: Christoph Hellwig <hch@infradead.org>
To: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 04/16] writeback: fix possible race when shutting down bdi
Date: Sun, 18 Jul 2010 02:47:20 -0400	[thread overview]
Message-ID: <20100718064720.GD23811@infradead.org> (raw)
In-Reply-To: <1279284312-2411-5-git-send-email-dedekind1@gmail.com>

On Fri, Jul 16, 2010 at 03:45:00PM +0300, Artem Bityutskiy wrote:
> From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> 
> Current bdi code has the following race between 'bdi_wb_shutdown()'
> and 'bdi_forker_thread()'.
> 
> Initial condition: BDI_pending is cleaned, bdi has no writeback thread,
> because it was inactive and exited, 'bdi_wb_shutdown()' and
> 'bdi_forker_thread()' are executed concurrently.

Wouldn't it be better to have a per-bdi mutex to serialize thread
creation and shutdown?  And please also kill the bit wait in favour
of a proper wait queue - the bit wait interface really is just a hack
for structures that are very size sensitive, which the backing device
is not.


  reply	other threads:[~2010-07-18  6:47 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-16 12:44 [RFC][PATCH 00/16] kill unnecessary bdi wakeups + cleanups Artem Bityutskiy
2010-07-16 12:44 ` [RFC][PATCH 01/16] writeback: do not self-wakeup Artem Bityutskiy
2010-07-18  6:44   ` Christoph Hellwig
2010-07-18  9:43     ` Artem Bityutskiy
2010-07-16 12:44 ` [RFC][PATCH 02/16] writeback: remove redundant list initialization Artem Bityutskiy
2010-07-18  6:44   ` Christoph Hellwig
2010-07-16 12:44 ` [RFC][PATCH 03/16] writeback: harmonize writeback threads naming Artem Bityutskiy
2010-07-18  6:45   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 04/16] writeback: fix possible race when shutting down bdi Artem Bityutskiy
2010-07-18  6:47   ` Christoph Hellwig [this message]
2010-07-20  8:58     ` Artem Bityutskiy
2010-07-16 12:45 ` [RFC][PATCH 05/16] writeback: fix possible race when creating bdi threads Artem Bityutskiy
2010-07-16 12:45 ` [RFC][PATCH 06/16] writeback: improve bdi_has_dirty_io Artem Bityutskiy
2010-07-18  6:49   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 07/16] writeback: do not lose wake-ups in the forker thread Artem Bityutskiy
2010-07-18  6:49   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 08/16] writeback: do not lose default bdi wake-ups Artem Bityutskiy
2010-07-18  6:52   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 09/16] writeback: do not lose wake-ups in bdi threads Artem Bityutskiy
2010-07-18  6:52   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 10/16] writeback: simplify bdi code a little Artem Bityutskiy
2010-07-18  6:56   ` Christoph Hellwig
2010-07-20 10:34     ` Artem Bityutskiy
2010-07-16 12:45 ` [RFC][PATCH 11/16] writeback: move last_active to bdi Artem Bityutskiy
2010-07-18  7:03   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 12/16] writeback: add to bdi_list in the forker thread Artem Bityutskiy
2010-07-18  6:58   ` Christoph Hellwig
2010-07-20 11:07     ` Artem Bityutskiy
2010-07-20 11:32     ` Artem Bityutskiy
2010-07-16 12:45 ` [RFC][PATCH 13/16] writeback: restructure bdi forker loop a little Artem Bityutskiy
2010-07-16 12:45 ` [RFC][PATCH 14/16] writeback: move bdi threads exiting logic to the forker thread Artem Bityutskiy
2010-07-18  7:02   ` Christoph Hellwig
2010-07-20 12:23     ` Artem Bityutskiy
2010-07-20 12:54     ` Artem Bityutskiy
2010-07-16 12:45 ` [RFC][PATCH 15/16] writeback: clean-up the warning about non-registered bdi Artem Bityutskiy
2010-07-18  7:03   ` Christoph Hellwig
2010-07-16 12:45 ` [RFC][PATCH 16/16] writeback: prevent unnecessary bdi threads wakeups Artem Bityutskiy
2010-07-18  7:45   ` Christoph Hellwig
2010-07-20 13:13     ` Artem Bityutskiy

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