From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Wu Fengguang <fengguang.wu@intel.com>,
linux-fsdevel@vger.kernel.org, Jens Axboe <jaxboe@fusionio.com>
Subject: Re: [PATCH 1/3] mm: Stop background writeback if there is other work queued for the thread
Date: Tue, 3 Aug 2010 12:33:21 -0400 [thread overview]
Message-ID: <20100803163321.GA21273@infradead.org> (raw)
In-Reply-To: <1280852440-13630-2-git-send-email-jack@suse.cz>
On Tue, Aug 03, 2010 at 06:20:38PM +0200, Jan Kara wrote:
> Background writeback and kupdate-style writeback are easily livelockable
> (from a definition of their target). This is inconvenient because it can
> make sync(1) stall forever waiting on its queued work to be finished.
> Fix the problem by interrupting background and kupdate writeback if there
> is some other work to do. We can return to them after completing all the
> queued work.
I don't think this is quite correct. If the only other callers was
fsync_filesystems that would be true, but we also have the odd
writeback_if_idle hack in ext4, and the bdi_start_writeback hack
in laptop mode.
next prev parent reply other threads:[~2010-08-03 16:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-03 16:20 [PATCH 0/3] Small writeback code fixes and improvements Jan Kara
2010-08-03 16:20 ` [PATCH 1/3] mm: Stop background writeback if there is other work queued for the thread Jan Kara
2010-08-03 16:33 ` Christoph Hellwig [this message]
2010-08-03 20:41 ` Jan Kara
2010-08-06 12:28 ` Christoph Hellwig
2010-08-03 16:20 ` [PATCH 2/3] mm: Fix writeback_in_progress() Jan Kara
2010-08-03 16:36 ` Christoph Hellwig
2010-08-03 20:55 ` Jan Kara
2010-08-06 12:34 ` Christoph Hellwig
2010-08-03 16:20 ` [PATCH 3/3] mm: Avoid resetting wb_start after each writeback round Jan Kara
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