Re: [PATCH 00/23] per device dirty throttling -v8

Andrew Morton
2007-08-08T21:21:46Z

On Wed, 08 Aug 2007 14:10:15 -0700
"Martin J. Bligh" <mbligh@mbligh.org> wrote:

> Why isn't this easily fixable by just adding an additional dirty
> flag that says atime has changed? Then we only cause a write
> when we remove the inode from the inode cache, if only atime
> is updated.

I think that could be made to work, and it would fix the performance
issue.

It is a behaviour change. At present ext3 (for example) commits everything
every five seconds. After a change like this, a crash+recovery could cause
a file's atime to go backwards by an arbitrarily large time interval - it
could easily be months.