From: Jan Kara <jack@suse.cz>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
jack@suse.cz, npiggin@kernel.dk
Subject: Re: [PATCH 0/2] radix-tree: fix writeback livelock avoidance code
Date: Wed, 25 Aug 2010 22:11:26 +0200 [thread overview]
Message-ID: <20100825201126.GF2738@quack.suse.cz> (raw)
In-Reply-To: <1282281727-15088-1-git-send-email-david@fromorbit.com>
On Fri 20-08-10 15:22:05, Dave Chinner wrote:
> The following two patches fix bugs in the new radix tree functionality used to
> implement the writeback livelock avoidance code. Both bugs manifest themselves
> as stray PAGECACHE_TAG_TOWRITE tags in the mapping->page_tree radix tree
> resulting in livelocks during tag lookups. More subtly, they also appear to
> result in writeback tree walks occasionally terminating early and so not
> actually writing all the pages they are supposed to.
>
> Please review and test - these are pretty serious problems for the writeback code.
OK, I've updated Andrew's radix tree test suite to use the latest
incarnation of radix-tree.c and added check to verify consistency of tags
in a radix tree. Without your patches, the new error check triggers almost
immediately for radix_tree_range_tag_if_tagged, with them the test passes.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
prev parent reply other threads:[~2010-08-25 20:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 5:22 [PATCH 0/2] radix-tree: fix writeback livelock avoidance code Dave Chinner
2010-08-20 5:22 ` [PATCH 1/2] radix-tree: clear all tags in radix_tree_node_rcu_free Dave Chinner
2010-08-20 8:00 ` Nick Piggin
2010-08-20 13:00 ` Jan Kara
2010-08-20 5:22 ` [PATCH 2/2] radix-tree: radix_tree_range_tag_if_tagged() can set incorrect tags Dave Chinner
2010-08-20 8:02 ` Nick Piggin
2010-08-20 13:39 ` Jan Kara
2010-08-20 13:51 ` [PATCH 0/2] radix-tree: fix writeback livelock avoidance code Jan Kara
2010-08-20 14:29 ` Dave Chinner
2010-08-25 20:11 ` Jan Kara [this message]
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