Re: queue reference counting

[Jens Axboe <axboe@suse.de>]

On Thu, Aug 07 2003, Nick Piggin wrote:
> 
> 
> Jens Axboe wrote:
> 
> >On Thu, Aug 07 2003, Pavel Machek wrote:
> >
> >>Hi!
> >>
> >>
> >>>I ported `subj` to 2.6.0-test2. I do not yet have idea if it works,
> >>>but it compiles ;-).
> >>>
> >>It compiles, it event boots, but it does not seem to have much effect
> >>:-(.
> >>
> >
> >Now that the queue reference counting is in the current bk tree, we are
> >that much closer to real modular io schedulers. I'll post the cfq with
> >priorities for that.
> >
> 
> OK, the QUEUE_FLAG_DEAD. I assume that will be set in blk_cleanup_queue?
> Then all remaining requests are flushed out of the queue?
> 
> This requires that a driver must be able to continue to process requests
> during the call to blk_cleanup_queue, and that blk_cleanup_queue might
> block, right? Is this acceptable, or should there be an earlier call to
> set QUEUE_FLAG_DEAD and ensure queue is flushed?

The plan was to add blk_shutdown_queue() to do this. And then make sure
AS checks the dead flag and doesn't hold back any requests.

-- 
Jens Axboe