Re: [PATCH 02/10] drm/radeon: add infrastructure for advanced ring synchronization

["j.glisse" <j.glisse@gmail.com>]

On Thu, May 24, 2012 at 09:49:06AM +0200, Christian König wrote:
> Signed-off-by: Christian König <deathsimple@vodafone.de>

Need a small improvement see below, otherwise

Reviewed-by: Jerome Glisse <jglisse@redhat.com>

> ---
>  drivers/gpu/drm/radeon/radeon.h       |   23 ++++++++++-
>  drivers/gpu/drm/radeon/radeon_fence.c |   73 +++++++++++++++++++++++++++++----
>  2 files changed, 85 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index 5e259b4..4e232c3 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -257,8 +257,8 @@ struct radeon_fence_driver {
>  	uint32_t			scratch_reg;
>  	uint64_t			gpu_addr;
>  	volatile uint32_t		*cpu_addr;
> -	/* seq is protected by ring emission lock */
> -	uint64_t			seq;
> +	/* sync_seq is protected by ring emission lock */
> +	uint64_t			sync_seq[RADEON_NUM_RINGS];
>  	atomic64_t			last_seq;
>  	unsigned long			last_activity;
>  	bool				initialized;
> @@ -288,6 +288,25 @@ int radeon_fence_wait_any(struct radeon_device *rdev,
>  struct radeon_fence *radeon_fence_ref(struct radeon_fence *fence);
>  void radeon_fence_unref(struct radeon_fence **fence);
>  unsigned radeon_fence_count_emitted(struct radeon_device *rdev, int ring);
> +bool radeon_fence_need_sync(struct radeon_fence *fence, int ring);
> +void radeon_fence_note_sync(struct radeon_fence *fence, int ring);
> +static inline struct radeon_fence *radeon_fence_later(struct radeon_fence *a,
> +						      struct radeon_fence *b)
> +{
> +	if (!a) {
> +		return b;
> +	}
> +
> +	if (!b) {
> +		return a;
> +	}

Please add :
BUG_ON(a->ring != b->ring);

So we can catch if someone badly use this function.

> +
> +	if (a->seq > b->seq) {
> +		return a;
> +	} else {
> +		return b;
> +	}
> +}
>  
>  /*
>   * Tiling registers
> diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
> index 401d346..7b55625 100644
> --- a/drivers/gpu/drm/radeon/radeon_fence.c
> +++ b/drivers/gpu/drm/radeon/radeon_fence.c
> @@ -72,7 +72,7 @@ int radeon_fence_emit(struct radeon_device *rdev,
>  	}
>  	kref_init(&((*fence)->kref));
>  	(*fence)->rdev = rdev;
> -	(*fence)->seq = ++rdev->fence_drv[ring].seq;
> +	(*fence)->seq = ++rdev->fence_drv[ring].sync_seq[ring];
>  	(*fence)->ring = ring;
>  	radeon_fence_ring_emit(rdev, ring, *fence);
>  	trace_radeon_fence_emit(rdev->ddev, (*fence)->seq);
> @@ -449,7 +449,7 @@ int radeon_fence_wait_next_locked(struct radeon_device *rdev, int ring)
>  	 * wait.
>  	 */
>  	seq = atomic64_read(&rdev->fence_drv[ring].last_seq) + 1ULL;
> -	if (seq >= rdev->fence_drv[ring].seq) {
> +	if (seq >= rdev->fence_drv[ring].sync_seq[ring]) {
>  		/* nothing to wait for, last_seq is
>  		   already the last emited fence */
>  		return -ENOENT;
> @@ -464,7 +464,7 @@ int radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring)
>  	 * activity can be scheduled so there won't be concurrent access
>  	 * to seq value.
>  	 */
> -	return radeon_fence_wait_seq(rdev, rdev->fence_drv[ring].seq,
> +	return radeon_fence_wait_seq(rdev, rdev->fence_drv[ring].sync_seq[ring],
>  				     ring, false, false);
>  }
>  
> @@ -492,7 +492,8 @@ unsigned radeon_fence_count_emitted(struct radeon_device *rdev, int ring)
>  	 * but it's ok to report slightly wrong fence count here.
>  	 */
>  	radeon_fence_process(rdev, ring);
> -	emitted = rdev->fence_drv[ring].seq - atomic64_read(&rdev->fence_drv[ring].last_seq);
> +	emitted = rdev->fence_drv[ring].sync_seq[ring]
> +		- atomic64_read(&rdev->fence_drv[ring].last_seq);
>  	/* to avoid 32bits warp around */
>  	if (emitted > 0x10000000) {
>  		emitted = 0x10000000;
> @@ -500,6 +501,51 @@ unsigned radeon_fence_count_emitted(struct radeon_device *rdev, int ring)
>  	return (unsigned)emitted;
>  }
>  
> +bool radeon_fence_need_sync(struct radeon_fence *fence, int dst_ring)
> +{
> +	struct radeon_fence_driver *fdrv;
> +
> +	if (!fence) {
> +		return false;
> +	}
> +
> +	if (fence->ring == dst_ring) {
> +		return false;
> +	}
> +
> +	/* we are protected by the ring mutex */
> +	fdrv = &fence->rdev->fence_drv[dst_ring];
> +	if (fence->seq <= fdrv->sync_seq[fence->ring]) {
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
> +void radeon_fence_note_sync(struct radeon_fence *fence, int dst_ring)
> +{
> +	struct radeon_fence_driver *dst, *src;
> +	unsigned i;
> +
> +	if (!fence) {
> +		return;
> +	}
> +
> +	if (fence->ring == dst_ring) {
> +		return;
> +	}
> +
> +	/* we are protected by the ring mutex */
> +	src = &fence->rdev->fence_drv[fence->ring];
> +	dst = &fence->rdev->fence_drv[dst_ring];
> +	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
> +		if (i == dst_ring) {
> +			continue;
> +		}
> +		dst->sync_seq[i] = max(dst->sync_seq[i], src->sync_seq[i]);
> +	}
> +}
> +
>  int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
>  {
>  	uint64_t index;
> @@ -521,7 +567,7 @@ int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
>  	}
>  	rdev->fence_drv[ring].cpu_addr = &rdev->wb.wb[index/4];
>  	rdev->fence_drv[ring].gpu_addr = rdev->wb.gpu_addr + index;
> -	radeon_fence_write(rdev, rdev->fence_drv[ring].seq, ring);
> +	radeon_fence_write(rdev, rdev->fence_drv[ring].sync_seq[ring], ring);
>  	rdev->fence_drv[ring].initialized = true;
>  	dev_info(rdev->dev, "fence driver on ring %d use gpu addr 0x%016llx and cpu addr 0x%p\n",
>  		 ring, rdev->fence_drv[ring].gpu_addr, rdev->fence_drv[ring].cpu_addr);
> @@ -530,10 +576,13 @@ int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
>  
>  static void radeon_fence_driver_init_ring(struct radeon_device *rdev, int ring)
>  {
> +	int i;
> +
>  	rdev->fence_drv[ring].scratch_reg = -1;
>  	rdev->fence_drv[ring].cpu_addr = NULL;
>  	rdev->fence_drv[ring].gpu_addr = 0;
> -	rdev->fence_drv[ring].seq = 0;
> +	for (i = 0; i < RADEON_NUM_RINGS; ++i)
> +		rdev->fence_drv[ring].sync_seq[i] = 0;
>  	atomic64_set(&rdev->fence_drv[ring].last_seq, 0);
>  	rdev->fence_drv[ring].last_activity = jiffies;
>  	rdev->fence_drv[ring].initialized = false;
> @@ -579,7 +628,7 @@ static int radeon_debugfs_fence_info(struct seq_file *m, void *data)
>  	struct drm_info_node *node = (struct drm_info_node *)m->private;
>  	struct drm_device *dev = node->minor->dev;
>  	struct radeon_device *rdev = dev->dev_private;
> -	int i;
> +	int i, j;
>  
>  	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
>  		if (!rdev->fence_drv[i].initialized)
> @@ -588,8 +637,14 @@ static int radeon_debugfs_fence_info(struct seq_file *m, void *data)
>  		seq_printf(m, "--- ring %d ---\n", i);
>  		seq_printf(m, "Last signaled fence 0x%016llx\n",
>  			   (unsigned long long)atomic64_read(&rdev->fence_drv[i].last_seq));
> -		seq_printf(m, "Last emitted  0x%016llx\n",
> -			   rdev->fence_drv[i].seq);
> +		seq_printf(m, "Last emitted        0x%016llx\n",
> +			   rdev->fence_drv[i].sync_seq[i]);
> +
> +		for (j = 0; j < RADEON_NUM_RINGS; ++j) {
> +			if (i != j && rdev->fence_drv[j].initialized)
> +				seq_printf(m, "Last sync to ring %d 0x%016llx\n",
> +					   j, rdev->fence_drv[i].sync_seq[j]);
> +		}
>  	}
>  	return 0;
>  }
> -- 
> 1.7.9.5
>