Re: [PATCH, RFC] Don't do page stablization if !CONFIG_BLKDEV_INTEGRITY

Ted Ts'o
2012-03-09T16:20:18Z

On Thu, Mar 08, 2012 at 08:02:07PM -0500, Chris Mason wrote:
> > Right before submission to the bio layer? Or right before the device
> > driver sends the request to the host bus adapter? I was thinking of
> > the latter....
>
> blktrace can probably give us numbers for how big that wait is, but
> hopefully it is very small. If it is too big, you can always bump
> nr_requests.

Not necessarily; things can get stalled for quite a while due to
ionice or io rate throttling. There's quite a lot that can happen
after submit_bio, at the cfq layer, for example.

- Ted