drm/i915: Merge wait_for_timelines with retire_request

wait_for_timelines is essentially the same loop as retiring requests
(with an extra timeout), so merge the two into one routine.

v2: i915_retire_requests_timeout and keep VT'd w/a as !interruptible

Signed-off-by: Chris Wilson <[email protected]>
Reviewed-by: Tvrtko Ursulin <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: ickle

drivers/gpu/drm/i915/gem/i915_gem_mman.c

@@ -432,9 +432,7 @@ static int create_mmap_offset(struct drm_i915_gem_object *obj)
 
 	/* Attempt to reap some mmap space from dead objects */
 	do {
-		err = i915_gem_wait_for_idle(i915,
-					     I915_WAIT_INTERRUPTIBLE,
-					     MAX_SCHEDULE_TIMEOUT);
+		err = i915_gem_wait_for_idle(i915, MAX_SCHEDULE_TIMEOUT);
 		if (err)
 			break;
 

drivers/gpu/drm/i915/gem/i915_gem_pm.c

@@ -59,9 +59,7 @@ static bool switch_to_kernel_context_sync(struct intel_gt *gt)
 {
 	bool result = !intel_gt_is_wedged(gt);
 
-	if (i915_gem_wait_for_idle(gt->i915,
-				   I915_WAIT_FOR_IDLE_BOOST,
-				   I915_GEM_IDLE_TIMEOUT) == -ETIME) {
+	if (i915_gem_wait_for_idle(gt->i915, I915_GEM_IDLE_TIMEOUT) == -ETIME) {
 		/* XXX hide warning from gem_eio */
 		if (i915_modparams.reset) {
 			dev_err(gt->i915->drm.dev,

drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c

@@ -1137,7 +1137,7 @@ __sseu_finish(const char *name,
 
 	if ((flags & TEST_IDLE) && ret == 0) {
 		ret = i915_gem_wait_for_idle(ce->engine->i915,
-					     0, MAX_SCHEDULE_TIMEOUT);
+					     MAX_SCHEDULE_TIMEOUT);
 		if (ret)
 			return ret;
 

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

@@ -196,8 +196,7 @@ int intel_gt_resume(struct intel_gt *gt)
 
 static void wait_for_idle(struct intel_gt *gt)
 {
-	if (i915_gem_wait_for_idle(gt->i915, 0,
-				   I915_GEM_IDLE_TIMEOUT) == -ETIME) {
+	if (i915_gem_wait_for_idle(gt->i915, I915_GEM_IDLE_TIMEOUT) == -ETIME) {
 		/*
 		 * Forcibly cancel outstanding work and leave
 		 * the gpu quiet.

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3635,9 +3635,7 @@ i915_drop_caches_set(void *data, u64 val)
 		i915_retire_requests(i915);
 
 	if (val & (DROP_IDLE | DROP_ACTIVE)) {
-		ret = i915_gem_wait_for_idle(i915,
-					     I915_WAIT_INTERRUPTIBLE,
-					     MAX_SCHEDULE_TIMEOUT);
+		ret = i915_gem_wait_for_idle(i915, MAX_SCHEDULE_TIMEOUT);
 		if (ret)
 			return ret;
 	}

drivers/gpu/drm/i915/i915_drv.h

@@ -2321,8 +2321,7 @@ void i915_gem_driver_register(struct drm_i915_private *i915);
 void i915_gem_driver_unregister(struct drm_i915_private *i915);
 void i915_gem_driver_remove(struct drm_i915_private *dev_priv);
 void i915_gem_driver_release(struct drm_i915_private *dev_priv);
-int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
-			   unsigned int flags, long timeout);
+int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv, long timeout);
 void i915_gem_suspend(struct drm_i915_private *dev_priv);
 void i915_gem_suspend_late(struct drm_i915_private *dev_priv);
 void i915_gem_resume(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/i915_gem.c

@@ -883,80 +883,21 @@ void i915_gem_runtime_suspend(struct drm_i915_private *i915)
 	}
 }
 
-static long
-wait_for_timelines(struct intel_gt *gt, unsigned int wait, long timeout)
-{
-	struct intel_gt_timelines *timelines = &gt->timelines;
-	struct intel_timeline *tl;
-	unsigned long flags;
-
-	spin_lock_irqsave(&timelines->lock, flags);
-	list_for_each_entry(tl, &timelines->active_list, link) {
-		struct dma_fence *fence;
-
-		fence = i915_active_fence_get(&tl->last_request);
-		if (!fence)
-			continue;
-
-		spin_unlock_irqrestore(&timelines->lock, flags);
-
-		if (!dma_fence_is_i915(fence)) {
-			timeout = dma_fence_wait_timeout(fence,
-							 flags & I915_WAIT_INTERRUPTIBLE,
-							 timeout);
-		} else {
-			struct i915_request *rq = to_request(fence);
-
-			/*
-			 * "Race-to-idle".
-			 *
-			 * Switching to the kernel context is often used as
-			 * a synchronous step prior to idling, e.g. in suspend
-			 * for flushing all current operations to memory before
-			 * sleeping. These we want to complete as quickly as
-			 * possible to avoid prolonged stalls, so allow the gpu
-			 * to boost to maximum clocks.
-			 */
-			if (flags & I915_WAIT_FOR_IDLE_BOOST)
-				gen6_rps_boost(rq);
-
-			timeout = i915_request_wait(rq, flags, timeout);
-		}
-
-		dma_fence_put(fence);
-		if (timeout < 0)
-			return timeout;
-
-		/* restart after reacquiring the lock */
-		spin_lock_irqsave(&timelines->lock, flags);
-		tl = list_entry(&timelines->active_list, typeof(*tl), link);
-	}
-	spin_unlock_irqrestore(&timelines->lock, flags);
-
-	return timeout;
-}
-
-int i915_gem_wait_for_idle(struct drm_i915_private *i915,
-			   unsigned int flags, long timeout)
+int i915_gem_wait_for_idle(struct drm_i915_private *i915, long timeout)
 {
 	struct intel_gt *gt = &i915->gt;
 
 	/* If the device is asleep, we have no requests outstanding */
 	if (!intel_gt_pm_is_awake(gt))
 		return 0;
 
-	do {
-		timeout = wait_for_timelines(gt, flags, timeout);
-		if (timeout < 0)
-			return timeout;
-
+	while ((timeout = i915_retire_requests_timeout(i915, timeout)) > 0) {
 		cond_resched();
 		if (signal_pending(current))
 			return -EINTR;
+	}
 
-	} while (i915_retire_requests(i915));
-
-	return 0;
+	return timeout;
 }
 
 struct i915_vma *

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -46,9 +46,7 @@ static int ggtt_flush(struct drm_i915_private *i915)
 	 * the hopes that we can then remove contexts and the like only
 	 * bound by their active reference.
 	 */
-	return i915_gem_wait_for_idle(i915,
-				      I915_WAIT_INTERRUPTIBLE,
-				      MAX_SCHEDULE_TIMEOUT);
+	return i915_gem_wait_for_idle(i915, MAX_SCHEDULE_TIMEOUT);
 }
 
 static bool
@@ -126,6 +124,8 @@ i915_gem_evict_something(struct i915_address_space *vm,
 				    min_size, alignment, color,
 				    start, end, mode);
 
+	i915_retire_requests(vm->i915);
+
 search_again:
 	active = NULL;
 	INIT_LIST_HEAD(&eviction_list);
@@ -264,13 +264,13 @@ int i915_gem_evict_for_node(struct i915_address_space *vm,
 
 	trace_i915_gem_evict_node(vm, target, flags);
 
-	/* Retire before we search the active list. Although we have
+	/*
+	 * Retire before we search the active list. Although we have
 	 * reasonable accuracy in our retirement lists, we may have
 	 * a stray pin (preventing eviction) that can only be resolved by
 	 * retiring.
 	 */
-	if (!(flags & PIN_NONBLOCK))
-		i915_retire_requests(vm->i915);
+	i915_retire_requests(vm->i915);
 
 	if (i915_vm_has_cache_coloring(vm)) {
 		/* Expand search to cover neighbouring guard pages (or lack!) */

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -2528,7 +2528,9 @@ void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj,
 	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 
 	if (unlikely(ggtt->do_idle_maps)) {
-		if (i915_gem_wait_for_idle(dev_priv, 0, MAX_SCHEDULE_TIMEOUT)) {
+		/* XXX This does not prevent more requests being submitted! */
+		if (i915_retire_requests_timeout(dev_priv,
+						 -MAX_SCHEDULE_TIMEOUT)) {
 			DRM_ERROR("Failed to wait for idle; VT'd may hang.\n");
 			/* Wait a bit, in hopes it avoids the hang */
 			udelay(10);

drivers/gpu/drm/i915/i915_request.c

@@ -1508,13 +1508,19 @@ long i915_request_wait(struct i915_request *rq,
 	return timeout;
 }
 
-bool i915_retire_requests(struct drm_i915_private *i915)
+long i915_retire_requests_timeout(struct drm_i915_private *i915, long timeout)
 {
 	struct intel_gt_timelines *timelines = &i915->gt.timelines;
 	struct intel_timeline *tl, *tn;
+	unsigned long active_count = 0;
 	unsigned long flags;
+	bool interruptible;
 	LIST_HEAD(free);
 
+	interruptible = true;
+	if (timeout < 0)
+		timeout = -timeout, interruptible = false;
+
 	spin_lock_irqsave(&timelines->lock, flags);
 	list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
 		if (!mutex_trylock(&tl->mutex))
@@ -1525,13 +1531,27 @@ bool i915_retire_requests(struct drm_i915_private *i915)
 		tl->active_count++; /* pin the list element */
 		spin_unlock_irqrestore(&timelines->lock, flags);
 
+		if (timeout > 0) {
+			struct dma_fence *fence;
+
+			fence = i915_active_fence_get(&tl->last_request);
+			if (fence) {
+				timeout = dma_fence_wait_timeout(fence,
+								 interruptible,
+								 timeout);
+				dma_fence_put(fence);
+			}
+		}
+
 		retire_requests(tl);
 
 		spin_lock_irqsave(&timelines->lock, flags);
 
 		/* Resume iteration after dropping lock */
 		list_safe_reset_next(tl, tn, link);
-		if (!--tl->active_count)
+		if (--tl->active_count)
+			active_count += !!rcu_access_pointer(tl->last_request.fence);
+		else
 			list_del(&tl->link);
 
 		mutex_unlock(&tl->mutex);
@@ -1547,7 +1567,7 @@ bool i915_retire_requests(struct drm_i915_private *i915)
 	list_for_each_entry_safe(tl, tn, &free, link)
 		__intel_timeline_free(&tl->kref);
 
-	return !list_empty(&timelines->active_list);
+	return active_count ? timeout : 0;
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)