[Intel-gfx] [PATCH 04/12] drm/i915: Track active by VMA instead of object

Daniel Vetter daniel at ffwll.ch
Tue Jul 23 18:48:09 CEST 2013


On Sun, Jul 21, 2013 at 07:08:11PM -0700, Ben Widawsky wrote:
> Even though we want to be able to track active by VMA, the rest of the
> code is still using objects for most internal APIs. To solve this,
> create an object_is_active() function to help us in converting over to
> VMA usage.
> 
> Because we intend to keep around some functions that care about objects,
> and not VMAs, having this function around will be useful even as we
> begin to use VMAs more in function arguments.
> 
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>

Still not really convinced. For access synchronization we don't care
through which vm a bo is still access, only how (read/write) and when was
the last access (ring + seqno).

Note that this means that the per-vm lru doesn't really need an
active/inactive split anymore, for evict_something we only care about the
ordering and not whether a bo is active or not. unbind() will care but I'm
not sure that the "same bo in multiple address spaces needs to be evicted"
use-case is something we even should care about.

So imo this commit needs a good justificatio for _why_ we want to track
active per-vma. Atm I don't see a use-case, but I see complexity.
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_drv.h            | 15 +++----
>  drivers/gpu/drm/i915/i915_gem.c            | 64 ++++++++++++++++++------------
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c |  2 +-
>  3 files changed, 48 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index f809204..bdce9c1 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -541,6 +541,13 @@ struct i915_vma {
>  	struct drm_i915_gem_object *obj;
>  	struct i915_address_space *vm;
>  
> +	/**
> +	 * This is set if the object is on the active lists (has pending
> +	 * rendering and so a non-zero seqno), and is not set if it i s on
> +	 * inactive (ready to be unbound) list.
> +	 */
> +	unsigned int active:1;
> +
>  	/** This object's place on the active/inactive lists */
>  	struct list_head mm_list;
>  
> @@ -1266,13 +1273,6 @@ struct drm_i915_gem_object {
>  	struct list_head exec_list;
>  
>  	/**
> -	 * This is set if the object is on the active lists (has pending
> -	 * rendering and so a non-zero seqno), and is not set if it i s on
> -	 * inactive (ready to be unbound) list.
> -	 */
> -	unsigned int active:1;
> -
> -	/**
>  	 * This is set if the object has been written to since last bound
>  	 * to the GTT
>  	 */
> @@ -1726,6 +1726,7 @@ static inline void i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
>  int __must_check i915_mutex_lock_interruptible(struct drm_device *dev);
>  int i915_gem_object_sync(struct drm_i915_gem_object *obj,
>  			 struct intel_ring_buffer *to);
> +bool i915_gem_object_is_active(struct drm_i915_gem_object *obj);
>  void i915_gem_object_move_to_active(struct drm_i915_gem_object *obj,
>  				    struct i915_address_space *vm,
>  				    struct intel_ring_buffer *ring);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 6bdf89d..9ea6424 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -119,10 +119,22 @@ int i915_mutex_lock_interruptible(struct drm_device *dev)
>  	return 0;
>  }
>  
> +/* NB: Not the same as !i915_gem_object_is_inactive */
> +bool i915_gem_object_is_active(struct drm_i915_gem_object *obj)
> +{
> +	struct i915_vma *vma;
> +
> +	list_for_each_entry(vma, &obj->vma_list, vma_link)
> +		if (vma->active)
> +			return true;
> +
> +	return false;
> +}
> +
>  static inline bool
>  i915_gem_object_is_inactive(struct drm_i915_gem_object *obj)
>  {
> -	return i915_gem_obj_bound_any(obj) && !obj->active;
> +	return i915_gem_obj_bound_any(obj) && !i915_gem_object_is_active(obj);
>  }
>  
>  int
> @@ -1883,14 +1895,14 @@ i915_gem_object_move_to_active(struct drm_i915_gem_object *obj,
>  	}
>  	obj->ring = ring;
>  
> +	/* Move from whatever list we were on to the tail of execution. */
> +	vma = i915_gem_obj_to_vma(obj, vm);
>  	/* Add a reference if we're newly entering the active list. */
> -	if (!obj->active) {
> +	if (!vma->active) {
>  		drm_gem_object_reference(&obj->base);
> -		obj->active = 1;
> +		vma->active = 1;
>  	}
>  
> -	/* Move from whatever list we were on to the tail of execution. */
> -	vma = i915_gem_obj_to_vma(obj, vm);
>  	list_move_tail(&vma->mm_list, &vm->active_list);
>  	list_move_tail(&obj->ring_list, &ring->active_list);
>  
> @@ -1911,16 +1923,23 @@ i915_gem_object_move_to_active(struct drm_i915_gem_object *obj,
>  }
>  
>  static void
> -i915_gem_object_move_to_inactive(struct drm_i915_gem_object *obj,
> -				 struct i915_address_space *vm)
> +i915_gem_object_move_to_inactive(struct drm_i915_gem_object *obj)
>  {
> +	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
> +	struct i915_address_space *vm;
>  	struct i915_vma *vma;
> +	int i = 0;
>  
>  	BUG_ON(obj->base.write_domain & ~I915_GEM_GPU_DOMAINS);
> -	BUG_ON(!obj->active);
>  
> -	vma = i915_gem_obj_to_vma(obj, vm);
> -	list_move_tail(&vma->mm_list, &vm->inactive_list);
> +	list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
> +		vma = i915_gem_obj_to_vma(obj, vm);
> +		if (!vma || !vma->active)
> +			continue;
> +		list_move_tail(&vma->mm_list, &vm->inactive_list);
> +		vma->active = 0;
> +		i++;
> +	}
>  
>  	list_del_init(&obj->ring_list);
>  	obj->ring = NULL;
> @@ -1932,8 +1951,8 @@ i915_gem_object_move_to_inactive(struct drm_i915_gem_object *obj,
>  	obj->last_fenced_seqno = 0;
>  	obj->fenced_gpu_access = false;
>  
> -	obj->active = 0;
> -	drm_gem_object_unreference(&obj->base);
> +	while (i--)
> +		drm_gem_object_unreference(&obj->base);
>  
>  	WARN_ON(i915_verify_lists(dev));
>  }
> @@ -2254,15 +2273,13 @@ static void i915_gem_reset_ring_lists(struct drm_i915_private *dev_priv,
>  	}
>  
>  	while (!list_empty(&ring->active_list)) {
> -		struct i915_address_space *vm;
>  		struct drm_i915_gem_object *obj;
>  
>  		obj = list_first_entry(&ring->active_list,
>  				       struct drm_i915_gem_object,
>  				       ring_list);
>  
> -		list_for_each_entry(vm, &dev_priv->vm_list, global_link)
> -			i915_gem_object_move_to_inactive(obj, vm);
> +		i915_gem_object_move_to_inactive(obj);
>  	}
>  }
>  
> @@ -2348,8 +2365,6 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring)
>  	 * by the ringbuffer to the flushing/inactive lists as appropriate.
>  	 */
>  	while (!list_empty(&ring->active_list)) {
> -		struct drm_i915_private *dev_priv = ring->dev->dev_private;
> -		struct i915_address_space *vm;
>  		struct drm_i915_gem_object *obj;
>  
>  		obj = list_first_entry(&ring->active_list,
> @@ -2359,8 +2374,8 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring)
>  		if (!i915_seqno_passed(seqno, obj->last_read_seqno))
>  			break;
>  
> -		list_for_each_entry(vm, &dev_priv->vm_list, global_link)
> -			i915_gem_object_move_to_inactive(obj, vm);
> +		BUG_ON(!i915_gem_object_is_active(obj));
> +		i915_gem_object_move_to_inactive(obj);
>  	}
>  
>  	if (unlikely(ring->trace_irq_seqno &&
> @@ -2435,7 +2450,7 @@ i915_gem_object_flush_active(struct drm_i915_gem_object *obj)
>  {
>  	int ret;
>  
> -	if (obj->active) {
> +	if (i915_gem_object_is_active(obj)) {
>  		ret = i915_gem_check_olr(obj->ring, obj->last_read_seqno);
>  		if (ret)
>  			return ret;
> @@ -2500,7 +2515,7 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>  	if (ret)
>  		goto out;
>  
> -	if (obj->active) {
> +	if (i915_gem_object_is_active(obj)) {
>  		seqno = obj->last_read_seqno;
>  		ring = obj->ring;
>  	}
> @@ -3850,7 +3865,7 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
>  	 */
>  	ret = i915_gem_object_flush_active(obj);
>  
> -	args->busy = obj->active;
> +	args->busy = i915_gem_object_is_active(obj);
>  	if (obj->ring) {
>  		BUILD_BUG_ON(I915_NUM_RINGS > 16);
>  		args->busy |= intel_ring_flag(obj->ring) << 16;
> @@ -4716,13 +4731,12 @@ i915_gem_inactive_shrink(struct shrinker *shrinker, struct shrink_control *sc)
>  			cnt += obj->base.size >> PAGE_SHIFT;
>  
>  	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
> -		if (obj->active)
> +		if (i915_gem_object_is_active(obj))
>  			continue;
>  
>  		i915_gem_object_flush_gtt_write_domain(obj);
>  		i915_gem_object_flush_cpu_write_domain(obj);
> -		/* FIXME: Can't assume global gtt */
> -		i915_gem_object_move_to_inactive(obj, &dev_priv->gtt.base);
> +		i915_gem_object_move_to_inactive(obj);
>  
>  		if (obj->pin_count == 0 && obj->pages_pin_count == 0)
>  			cnt += obj->base.size >> PAGE_SHIFT;
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 819d8d8..8d2643b 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -251,7 +251,7 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
>  	}
>  
>  	/* We can't wait for rendering with pagefaults disabled */
> -	if (obj->active && in_atomic())
> +	if (i915_gem_object_is_active(obj) && in_atomic())
>  		return -EFAULT;
>  
>  	reloc->delta += target_offset;
> -- 
> 1.8.3.3
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch



More information about the Intel-gfx mailing list