[Intel-gfx] [PATCH] drm/i915: Move global activity tracking from GEM to GT

[Tvrtko Ursulin]

On 22/07/2019 22:46, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2019-07-22 13:16:38)
>>
>> On 18/07/2019 13:42, Chris Wilson wrote:
>>> As our global unpark/park keep track of the number of active users, we
>>> can simply move the accounting from the GEM layer to the base GT layer.
>>> It was placed originally inside GEM to benefit from the 100ms extra
>>> delay on idleness, but that has been eliminated and now there is no
>>> substantive difference between the layers. In moving it, we move another
>>> piece of the puzzle out from underneath struct_mutex.
>>>
>>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>>> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>> ---
>>>    drivers/gpu/drm/i915/gem/i915_gem_pm.c | 4 ----
>>>    drivers/gpu/drm/i915/gt/intel_gt_pm.c  | 5 +++++
>>>    2 files changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
>>> index 8faf262278ae..1afb04660725 100644
>>> --- a/drivers/gpu/drm/i915/gem/i915_gem_pm.c
>>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
>>> @@ -9,7 +9,6 @@
>>>    #include "gt/intel_gt_pm.h"
>>>    
>>>    #include "i915_drv.h"
>>> -#include "i915_globals.h"
>>>    
>>>    static void call_idle_barriers(struct intel_engine_cs *engine)
>>>    {
>>> @@ -41,8 +40,6 @@ static void i915_gem_park(struct drm_i915_private *i915)
>>>    
>>>        intel_timelines_park(i915);
>>>        i915_vma_parked(i915);
>>> -
>>> -     i915_globals_park();
>>
>> Benefit of this placement was also that what will be freed on parking
>> was freed by this point so shrinking of slabs is effective. If you move
>> it to gt parking then that runs to early. So I think it is better that
>> it stays where it is.
> 
> But there's nothing here. You are imaging things. call_idle_barriers and
> batch_pool are in engine_park, timelines_park is gone, and vma_parked is
> now a timer.

I was thinking about slab shrinkers. They do seem to be called from 
i915_globals_park or I am still imagining?

Regards,

Tvrtko