[Intel-gfx] [PATCH 05/11] drm/i915: Introduce i915_timeline.mutex

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-02-28 07:43:41)
> 
> On 26/02/2019 10:23, Chris Wilson wrote:
> > A simple mutex used for guarding the flow of requests in and out of the
> > timeline. In the short-term, it will be used only to guard the addition
> > of requests into the timeline, taken on alloc and released on commit so
> > that only one caller can construct a request into the timeline
> > (important as the seqno and ring pointers must be serialised). This will
> > be used by observers to ensure that the seqno/hwsp is stable. Later,
> > when we have reduced retiring to only operate on a single timeline at a
> > time, we can then use the mutex as the sole guard required for retiring.
> 
> At which point does this gets used? In media scalability patches or later?

It is in this series to explicitly lock i915_timeline_read_hswp(). It's
real calling is in removing the global ordering, as then request
alloc/retirement is under each timeline lock, and nothing but the
timeline locks.
-Chris