Commit 298287f6 authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm: Signal fences sooner 



Nothing we do to in update_fences() can't be done in an atomic context,
so move this into the GPU's irq context to reduce latency (and call
dma_fence_signal() so we aren't relying on dma_fence_is_signaled() which
would defeat the purpose).

Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20210726144359.2179302-3-robdclark@gmail.com


Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
parent da3d378d

drivers/gpu/drm/msm/msm_gpu.c

+26 −18
Original line number Diff line number Diff line
@@ -278,16 +278,18 @@ static void update_fences(struct msm_gpu *gpu, struct msm_ringbuffer *ring, 
		uint32_t fence)

{

	struct msm_gem_submit *submit;

	unsigned long flags;



	spin_lock(&ring->submit_lock);

	spin_lock_irqsave(&ring->submit_lock, flags);

	list_for_each_entry(submit, &ring->submits, node) {

		if (submit->seqno > fence)

			break;



		msm_update_fence(submit->ring->fctx,

			submit->fence->seqno);

		dma_fence_signal(submit->fence);

	}

	spin_unlock(&ring->submit_lock);

	spin_unlock_irqrestore(&ring->submit_lock, flags);

}



#ifdef CONFIG_DEV_COREDUMP
@@ -443,15 +445,16 @@ static struct msm_gem_submit * 
find_submit(struct msm_ringbuffer *ring, uint32_t fence)

{

	struct msm_gem_submit *submit;

	unsigned long flags;



	spin_lock(&ring->submit_lock);

	spin_lock_irqsave(&ring->submit_lock, flags);

	list_for_each_entry(submit, &ring->submits, node) {

		if (submit->seqno == fence) {

			spin_unlock(&ring->submit_lock);

			spin_unlock_irqrestore(&ring->submit_lock, flags);

			return submit;

		}

	}

	spin_unlock(&ring->submit_lock);

	spin_unlock_irqrestore(&ring->submit_lock, flags);



	return NULL;

}
@@ -547,11 +550,12 @@ static void recover_worker(struct kthread_work *work) 
		 */

		for (i = 0; i < gpu->nr_rings; i++) {

			struct msm_ringbuffer *ring = gpu->rb[i];

			unsigned long flags;



			spin_lock(&ring->submit_lock);

			spin_lock_irqsave(&ring->submit_lock, flags);

			list_for_each_entry(submit, &ring->submits, node)

				gpu->funcs->submit(gpu, submit);

			spin_unlock(&ring->submit_lock);

			spin_unlock_irqrestore(&ring->submit_lock, flags);

		}

	}
@@ -641,7 +645,7 @@ static void hangcheck_handler(struct timer_list *t) 
		hangcheck_timer_reset(gpu);



	/* workaround for missing irq: */

	kthread_queue_work(gpu->worker, &gpu->retire_work);

	msm_gpu_retire(gpu);

}



/*
@@ -752,6 +756,7 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring, 
	int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;

	volatile struct msm_gpu_submit_stats *stats;

	u64 elapsed, clock = 0;

	unsigned long flags;

	int i;



	stats = &ring->memptrs->stats[index];
@@ -781,9 +786,9 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring, 
	pm_runtime_mark_last_busy(&gpu->pdev->dev);

	pm_runtime_put_autosuspend(&gpu->pdev->dev);



	spin_lock(&ring->submit_lock);

	spin_lock_irqsave(&ring->submit_lock, flags);

	list_del(&submit->node);

	spin_unlock(&ring->submit_lock);

	spin_unlock_irqrestore(&ring->submit_lock, flags);



	msm_gem_submit_put(submit);

}
@@ -798,11 +803,12 @@ static void retire_submits(struct msm_gpu *gpu) 


		while (true) {

			struct msm_gem_submit *submit = NULL;

			unsigned long flags;



			spin_lock(&ring->submit_lock);

			spin_lock_irqsave(&ring->submit_lock, flags);

			submit = list_first_entry_or_null(&ring->submits,

					struct msm_gem_submit, node);

			spin_unlock(&ring->submit_lock);

			spin_unlock_irqrestore(&ring->submit_lock, flags);



			/*

			 * If no submit, we are done.  If submit->fence hasn't
@@ -821,10 +827,6 @@ static void retire_submits(struct msm_gpu *gpu) 
static void retire_worker(struct kthread_work *work)

{

	struct msm_gpu *gpu = container_of(work, struct msm_gpu, retire_work);

	int i;



	for (i = 0; i < gpu->nr_rings; i++)

		update_fences(gpu, gpu->rb[i], gpu->rb[i]->memptrs->fence);



	retire_submits(gpu);

}
@@ -832,6 +834,11 @@ static void retire_worker(struct kthread_work *work) 
/* call from irq handler to schedule work to retire bo's */

void msm_gpu_retire(struct msm_gpu *gpu)

{

	int i;



	for (i = 0; i < gpu->nr_rings; i++)

		update_fences(gpu, gpu->rb[i], gpu->rb[i]->memptrs->fence);



	kthread_queue_work(gpu->worker, &gpu->retire_work);

	update_sw_cntrs(gpu);

}
@@ -842,6 +849,7 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit) 
	struct drm_device *dev = gpu->dev;

	struct msm_drm_private *priv = dev->dev_private;

	struct msm_ringbuffer *ring = submit->ring;

	unsigned long flags;

	int i;



	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
@@ -879,9 +887,9 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit) 
	 */

	msm_gem_submit_get(submit);



	spin_lock(&ring->submit_lock);

	spin_lock_irqsave(&ring->submit_lock, flags);

	list_add_tail(&submit->node, &ring->submits);

	spin_unlock(&ring->submit_lock);

	spin_unlock_irqrestore(&ring->submit_lock, flags);



	gpu->funcs->submit(gpu, submit);

	priv->lastctx = submit->queue->ctx;