Re: [PATCH] libata error handling fixes (ATAPI)

[Jeff Garzik]

Jens Axboe wrote:
> On Wed, Nov 16 2005, Jeff Garzik wrote:
>
> > Jens Axboe wrote:
> >
> > > I updated that patch, and converted IDE and SCSI to use it. See the
> > > results here:
> > >
> > > http://brick.kernel.dk/git/?p=linux-2.6-block.git;a=shortlog;h=blk-softirq
> > >
> > > The main change from the version posted last october is killing the
> > > 'slightly' overdesigned completion queue hashing.
> >
> > Nifty, I like.  Comments:
> >
> > * use of spin_lock_irq() in all completion paths now makes me nervous.
>
>
> Should be fine from the paths originating from blk_done_softirq(), as we
> know interrupts are enabled in the first place. But generally I agree,
> whenever in doubt always always use the irq saving variants.
>
>
> > * certainly it's what SCSI does now, but is a softirq really necessary? 
> > Using a tasklet would kill all that per-cpu code, and notifier.
>
>
> It would work fine with a tasklet of course, but it's going to generate
> a _lot_ of traffic on io busy systems so I felt a dedicated softirq was
> the way to go.

fair enough.  ACK.

	Jeff



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