Re: [PATCH 1/5] [BLOCK] Add 'discard' request handling

[David Woodhouse <dwmw2@infradead.org>]

On Fri, 2008-08-08 at 12:49 +0200, Jens Axboe wrote:
> This is what I came up with. You don't need the request discard flag,
> since you are using a specific request type for this. Additionally, we
> can move the request init where it is done for fs requests
> (init_req_from_bio) and get it set there. 

Hmmm. (qv)

> I also added the small bits for merging.

Nice. I was _hoping_ it would be that easy, but didn't want to get
involved with that yet. One tweak we might want to make to that would be
to allow discard requests to be _dropped_ if there's a subsequent write
to the same sectors -- if we expect it to be common that we deallocate
sectors then re-use them again before the discard request hits the disk,
that might be an interesting optimisation.

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation