Re: [RFC] [PATCH] Relative lazy atime

[Christoph Hellwig <hch@lst.de>]

On Wed, Aug 02, 2006 at 11:36:22PM -0700, Valerie Henson wrote:
> (Corrected Chris Wedgwood's name and email.)
> 
> My friend Akkana followed my advice to use noatime on one of her
> machines, but discovered that mutt was unusable because it always
> thought that new messages had arrived since the last time it had
> checked a folder (mbox format).  I thought this was a bummer, so I
> wrote a "relative lazy atime" patch which only updates the atime if
> the old atime was less than the ctime or mtime.  This is not the same
> as the lazy atime patch of yore[1], which maintained a list of inodes
> with dirty atimes and wrote them out on unmount.

Another idea, similar to how atime updates work in xfs currently might
be interesting:  Always update atime in core, but don't start a
transaction just for it - instead only flush it when you'd do it anyway,
that is another transaction or evicting the inode.