Commit 30084b14 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Flush other retirees inside intel_gt_retire_requests() 

Our goal in wait_for_idle (intel_gt_retire_requests) is to the current
workload *and* their idle barriers. This requires us to notice the late
arrival of those, which is done by inspecting the list of active
timelines. However, if a concurrent retirer is running that new timeline
may not be added until after we drop the lock -- so flush concurrent
retirers before we take the lock and inspect the list.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/878


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Acked-by: default avatarAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191223211008.2371613-1-chris@chris-wilson.co.uk
parent b42d3b15

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

+1 −1
Original line number Diff line number Diff line
@@ -282,7 +282,7 @@ static inline void __intel_engine_reset(struct intel_engine_cs *engine, 


bool intel_engines_are_idle(struct intel_gt *gt);

bool intel_engine_is_idle(struct intel_engine_cs *engine);

bool intel_engine_flush_submission(struct intel_engine_cs *engine);

void intel_engine_flush_submission(struct intel_engine_cs *engine);



void intel_engines_reset_default_submission(struct intel_gt *gt);

drivers/gpu/drm/i915/gt/intel_engine_cs.c

+1 −5
Original line number Diff line number Diff line
@@ -1047,10 +1047,9 @@ static bool ring_is_idle(struct intel_engine_cs *engine) 
	return idle;

}



bool intel_engine_flush_submission(struct intel_engine_cs *engine)

void intel_engine_flush_submission(struct intel_engine_cs *engine)

{

	struct tasklet_struct *t = &engine->execlists.tasklet;

	bool active = tasklet_is_locked(t);



	if (__tasklet_is_scheduled(t)) {

		local_bh_disable();
@@ -1061,13 +1060,10 @@ bool intel_engine_flush_submission(struct intel_engine_cs *engine) 
			tasklet_unlock(t);

		}

		local_bh_enable();

		active = true;

	}



	/* Otherwise flush the tasklet if it was running on another cpu */

	tasklet_unlock_wait(t);



	return active;

}



/**

drivers/gpu/drm/i915/gt/intel_gt_requests.c

+5 −11
Original line number Diff line number Diff line
@@ -26,21 +26,18 @@ static bool retire_requests(struct intel_timeline *tl) 
	return !i915_active_fence_isset(&tl->last_request);

}



static bool flush_submission(struct intel_gt *gt)

static void flush_submission(struct intel_gt *gt)

{

	struct intel_engine_cs *engine;

	enum intel_engine_id id;

	bool active = false;



	if (!intel_gt_pm_is_awake(gt))

		return false;

		return;



	for_each_engine(engine, gt, id) {

		active |= intel_engine_flush_submission(engine);

		active |= flush_work(&engine->retire_work);

		intel_engine_flush_submission(engine);

		flush_work(&engine->retire_work);

	}



	return active;

}



static void engine_retire(struct work_struct *work)
@@ -126,7 +123,6 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout) 
		timeout = -timeout, interruptible = false;



	flush_submission(gt); /* kick the ksoftirqd tasklets */



	spin_lock(&timelines->lock);

	list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {

		if (!mutex_trylock(&tl->mutex)) {
@@ -153,6 +149,7 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout) 


		active_count += !retire_requests(tl);



		flush_submission(gt); /* sync with concurrent retirees */

		spin_lock(&timelines->lock);



		/* Resume iteration after dropping lock */
@@ -173,9 +170,6 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout) 
	list_for_each_entry_safe(tl, tn, &free, link)

		__intel_timeline_free(&tl->kref);



	if (flush_submission(gt))

		active_count++;



	return active_count ? timeout : 0;

}

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