Re: [Lsf] IO less throttling and cgroup aware writeback (Was: Re: Preliminary Agenda and Activities for LSF)

Christoph Hellwig
2011-04-01T06:33:05Z

On Fri, Apr 01, 2011 at 03:36:05PM +1100, Dave Chinner wrote:
> > If that's a concern,
> > can filesystem mark that bio (REQ_META?) and throttling logic can possibly
> > let these bio pass through.
>
> We already tag most metadata IO in this way.

Actually we don't tag any I/O that way right now. That's mostly
because REQ_META assumes it's synchronous I/O and cfg and the block
layer give id additional priority, while in XFS metadata writes
are mostly asynchronous. We'll need a properly defined REQ_META
to use it, which currently is not the case.