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

[Tvrtko Ursulin]

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.

Regards,

Tvrtko

>   }
>   
>   static void idle_work_handler(struct work_struct *work)
> @@ -93,7 +90,6 @@ static int pm_notifier(struct notifier_block *nb,
>   
>   	switch (action) {
>   	case INTEL_GT_UNPARK:
> -		i915_globals_unpark();
>   		queue_delayed_work(i915->wq,
>   				   &i915->gem.retire_work,
>   				   round_jiffies_up_relative(HZ));
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> index 61ed912341f1..ce7733ee76cf 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> @@ -5,6 +5,7 @@
>    */
>   
>   #include "i915_drv.h"
> +#include "i915_globals.h"
>   #include "i915_params.h"
>   #include "intel_engine_pm.h"
>   #include "intel_gt.h"
> @@ -24,6 +25,8 @@ static int intel_gt_unpark(struct intel_wakeref *wf)
>   
>   	GEM_TRACE("\n");
>   
> +	i915_globals_unpark();
> +
>   	/*
>   	 * It seems that the DMC likes to transition between the DC states a lot
>   	 * when there are no connected displays (no active power domains) during
> @@ -77,6 +80,8 @@ static int intel_gt_park(struct intel_wakeref *wf)
>   	GEM_BUG_ON(!wakeref);
>   	intel_display_power_put(i915, POWER_DOMAIN_GT_IRQ, wakeref);
>   
> +	i915_globals_park();
> +
>   	return 0;
>   }
>   
>