[Intel-gfx] [PATCH 07/10] drm/i915: Store the reset counter when constructing a request

[Joonas Lahtinen]

On la, 2016-04-09 at 12:19 +0100, Chris Wilson wrote:
> As the request is only valid during the same global reset epoch, we can
> record the current reset_counter when constructing the request and reuse
> it when waiting upon that request in future. This removes a very hairy
> atomic check serialised by the struct_mutex at the time of waiting and
> allows us to transfer those waits to a central dispatcher for all
> waiters and all requests.
> 
> PS: With per-engine resets, we obviously cannot assume a global reset
> epoch for the requests - a per-engine epoch makes the most sense. The
> challenge then is how to handle checking in the waiter for when to break
> the wait, as the fine-grained reset may also want to requeue the
> request (i.e. the assumption that just because the epoch changes the
> request is completed may be broken - or we just avoid breaking that
> assumption with the fine-grained resets).
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Reviewed-by:: Daniel Vetter <daniel.vetter at ffwll.ch>

Double :'s.

Regards, Joonas

--
Joonas Lahtinen
Open Source Technology Center
Intel Corporation