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Commit 51fbd8de authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/pmu: Atomically acquire the gt_pm wakeref 



Currently, we only sample if the intel_gt is awake, but we acquire our
own runtime_pm wakeref. Since intel_gt has transitioned to tracking its
own wakeref, we can atomically test and acquire that wakeref instead.

v2: Take engine->wakeref for engine sampling

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190801233616.23007-1-chris@chris-wilson.co.uk
parent 518ea582

drivers/gpu/drm/i915/gt/intel_gt_pm.h

+7 −1
Original line number Diff line number Diff line
@@ -9,7 +9,8 @@ 


#include <linux/types.h>



struct intel_gt;

#include "intel_gt_types.h"

#include "intel_wakeref.h"



enum {

	INTEL_GT_UNPARK,
@@ -19,6 +20,11 @@ enum { 
void intel_gt_pm_get(struct intel_gt *gt);

void intel_gt_pm_put(struct intel_gt *gt);



static inline bool intel_gt_pm_get_if_awake(struct intel_gt *gt)

{

	return intel_wakeref_get_if_active(&gt->wakeref);

}



void intel_gt_pm_init_early(struct intel_gt *gt);



void intel_gt_sanitize(struct intel_gt *gt, bool force);

drivers/gpu/drm/i915/i915_pmu.c

+17 −23
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 
#include <linux/pm_runtime.h>



#include "gt/intel_engine.h"

#include "gt/intel_engine_pm.h"

#include "gt/intel_gt_pm.h"



#include "i915_drv.h"

#include "i915_pmu.h"
@@ -165,30 +167,26 @@ static void 
engines_sample(struct intel_gt *gt, unsigned int period_ns)

{

	struct drm_i915_private *i915 = gt->i915;

	struct intel_uncore *uncore = gt->uncore;

	struct intel_engine_cs *engine;

	enum intel_engine_id id;

	intel_wakeref_t wakeref;

	unsigned long flags;



	if ((i915->pmu.enable & ENGINE_SAMPLE_MASK) == 0)

		return;



	wakeref = 0;

	if (READ_ONCE(gt->awake))

		wakeref = intel_runtime_pm_get_if_in_use(&i915->runtime_pm);

	if (!wakeref)

		return;



	spin_lock_irqsave(&uncore->lock, flags);

	for_each_engine(engine, i915, id) {

		struct intel_engine_pmu *pmu = &engine->pmu;

		unsigned long flags;

		bool busy;

		u32 val;



		if (!intel_engine_pm_get_if_awake(engine))

			continue;



		spin_lock_irqsave(&engine->uncore->lock, flags);



		val = ENGINE_READ_FW(engine, RING_CTL);

		if (val == 0) /* powerwell off => engine idle */

			continue;

			goto skip;



		if (val & RING_WAIT)

			add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns);
@@ -209,10 +207,11 @@ engines_sample(struct intel_gt *gt, unsigned int period_ns) 
		}

		if (busy)

			add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns);

	}

	spin_unlock_irqrestore(&uncore->lock, flags);



	intel_runtime_pm_put(&i915->runtime_pm, wakeref);

skip:

		spin_unlock_irqrestore(&engine->uncore->lock, flags);

		intel_engine_pm_put(engine);

	}

}



static void
@@ -232,15 +231,10 @@ frequency_sample(struct intel_gt *gt, unsigned int period_ns) 
		u32 val;



		val = i915->gt_pm.rps.cur_freq;

		if (gt->awake) {

			intel_wakeref_t wakeref;



			with_intel_runtime_pm_if_in_use(&i915->runtime_pm,

							wakeref) {

				val = intel_uncore_read_notrace(uncore,

								GEN6_RPSTAT1);

		if (intel_gt_pm_get_if_awake(gt)) {

			val = intel_uncore_read_notrace(uncore, GEN6_RPSTAT1);

			val = intel_get_cagf(i915, val);

			}

			intel_gt_pm_put(gt);

		}



		add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_ACT],