[Intel-gfx] [PATCH 22/43] drm/i915: Introduce intel_context.pin_mutex for pin management

[Tvrtko Ursulin]

On 06/03/2019 14:51, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2019-03-06 14:43:13)
>>
>> On 06/03/2019 14:24, Chris Wilson wrote:
>>> Introduce a mutex to start locking the HW contexts independently of
>>> struct_mutex, with a view to reducing the coarse struct_mutex. The
>>> intel_context.pin_mutex is used to guard the transition to and from being
>>> pinned on the gpu, and so is required before starting to build any
>>> request. The intel_context will then remain pinned until the request
>>> completes, but the mutex can be released immediately unpin completion of
>>> pinning the context.
>>>
>>> A slight variant of the above is used by per-context sseu that wants to
>>> inspect the pinned status of the context, and requires that it remains
>>> stable (either !pinned or pinned) across its operation. By using the
>>> pin_mutex to serialise operations while pin_count==0, we can take that
>>> pin_mutex for stabilise the boolean pin status.
>>
>> Change log!
> 
> v2: no code changes, or at least I can only remember rewriting the
> commitmsg, so see above.

v2:
  * Improved commit message.
  * Dropped _gpu suffix from gen8_modify_rpcs_gpu.

Regards,

Tvrtko