Re: [PATCH 2/3] mm: Implement writeback livelock avoidance using page tagging

Andrew Morton
2010-02-12T19:42:49Z

On Fri, 12 Feb 2010 00:06:23 +0100
Jan Kara <jack@suse.cz> wrote:

> The idea is simple: Tag all pages that should be written back
> with a special tag (TOWRITE) in the radix tree. This can be done
> rather quickly and thus livelocks should not happen in practice.
> Then we start doing the hard work of locking pages and sending
> them to disk only for those pages that have TOWRITE tag set.

Adding a second pass across all the pages sounds expensive?