[Intel-gfx] [PATCH 36/73] drm/i915: Refactor activity tracking for requests

[Joonas Lahtinen]

On ma, 2016-08-01 at 10:10 +0100, Chris Wilson wrote:
> With the introduction of requests, we amplified the number of atomic
> refcounted objects we use and update every execbuffer; from none to
> several references, and a set of references that need to be changed. We
> also introduced interesting side-effects in the order of retiring
> requests and objects.
> 
> Instead of independently tracking the last request for an object, track
> the active objects for each request. The object will reside in the
> buffer list of its most recent active request and so we reduce the kref
> interchange to a list_move. Now retirements are entirely driven by the
> request, dramatically simplifying activity tracking on the object
> themselves, and removing the ambiguity between retiring objects and
> retiring requests.
> 
> Furthermore with the consolidation of managing the activity tracking
> centrally, we can look forward to using RCU to enable lockless lookup of
> the current active requests for an object. In the future, we will be
> able to query the status or wait upon rendering to an object without
> even touching the struct_mutex BKL.
> 
> All told, less code, simpler and faster, and more extensible.
> 
> v2: Add a typedef for the function pointer for convenience later.
> v3: Make the noop retirement callback explicit. Allow passing NULL to
> the init_gem_active() which is expanded to a common noop function.

s/init_gem_active/init_request_active/

Assuming you kept the changes to those,

Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation