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

Jeff Garzik
2005-11-16T13:23:49Z

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