Re: CD writing in future Linux (stirring up a hornets' nest)

[Jens Axboe]

On Thu, Feb 02 2006, Lee Revell wrote:
> On Thu, 2006-02-02 at 16:49 -0500, Jim Crilly wrote:
> > On 02/02/06 04:25:50PM -0500, Lee Revell wrote:
> > > On Thu, 2006-02-02 at 16:09 -0500, Jim Crilly wrote:
> > > > Apparently O_EXCL was added by Ubuntu and Debian to stop
> > > > burns being corrupted by hald polling the device while a disc is
> > > > being burned. 
> > > 
> > > IO priorities are the correct solution...
> > > 
> > > Lee
> > 
> > Is this something that's available now?
> > 
> 
> Hmm, actually I'm not sure it would make a difference, as I don't think
> CD writing goes through the regular IO scheduler.

Right, you can only prioritize "regular" io, not stuff sent with SG_IO.
So it'll help burning only for the case of getting the data required to
the buffer, not in getting that data out to the burner. The latter is
usually not a problem though, as these requests take a 'short cut'
directly to the dispatch queue.

-- 
Jens Axboe

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