Re: Linux 2.6.29

Alan Cox
2009-03-28T00:17:18Z

On Fri, 27 Mar 2009 16:38:35 -0400
Jeff Garzik <jeff@garzik.org> wrote:

> Christoph Hellwig wrote:
> > And please add a tuneable for the flush. Preferable a generic one at
> > the block device layer instead of the current mess where every
> > filesystem has a slightly different option for barrier usage.
>
> At the very least, IMO the block layer should be able to notice when
> barriers need not be translated into cache flushes. Most notably when
> wb cache is disabled on the drive, something easy to auto-detect, but
> probably a manual switch also, for people with enterprise battery-backed
> storage and such.

The storage drivers for those cases already generally know this and treat
cache flush requests as "has hit nvram", even the non enterprise ones.