Re: [PATCH 08/11] drm/i915: Track active vma requests

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

Hi,

On 14/12/15 11:36, Chris Wilson wrote:
> Hook the vma itself into the i915_gem_request_retire() so that we can
> accurately track when a solitary vma is inactive (as opposed to having

s/solitary/individual/ ?

> to wait for the entire object to be idle). This improves the interaction
> when using multiple contexts (with full-ppgtt) and eliminates some
> frequent list walking.

What list walking are you referring to? Maybe clarify in the commit message.

Anyway, looks surprisingly simple. Almost suspiciously simple, but I 
can't fault it:

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

>
> A side-effect is that we get an active vma reference for free. The
> consequence of this is shown in the next patch...
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/i915_debugfs.c        |  2 +-
>   drivers/gpu/drm/i915/i915_gem.c            | 36 ++++++++++++++++--------------
>   drivers/gpu/drm/i915/i915_gem_execbuffer.c |  2 ++
>   drivers/gpu/drm/i915/i915_gem_gtt.c        | 20 +++++++++++++++++
>   drivers/gpu/drm/i915/i915_gem_gtt.h        |  5 +++++
>   5 files changed, 47 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 179e3c5c5022..4df4ebbd56d6 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -356,7 +356,7 @@ static int per_file_stats(int id, void *ptr, void *data)
>   				continue;
>   		}
>
> -		if (obj->active) /* XXX per-vma statistic */
> +		if (vma->active)
>   			stats->active += vma->node.size;
>   		else
>   			stats->inactive += vma->node.size;
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 8a824c5d5348..1d21c5b79215 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2040,7 +2040,6 @@ i915_gem_object_retire__read(struct drm_i915_gem_request_active *active,
>   	int ring = request->engine->id;
>   	struct drm_i915_gem_object *obj =
>   		container_of(active, struct drm_i915_gem_object, last_read[ring]);
> -	struct i915_vma *vma;
>
>   	RQ_BUG_ON((obj->flags & (1 << (ring + I915_BO_ACTIVE_SHIFT))) == 0);
>
> @@ -2052,12 +2051,9 @@ i915_gem_object_retire__read(struct drm_i915_gem_request_active *active,
>   	 * so that we don't steal from recently used but inactive objects
>   	 * (unless we are forced to ofc!)
>   	 */
> -	list_move_tail(&obj->global_list, &request->i915->mm.bound_list);
> -
> -	list_for_each_entry(vma, &obj->vma_list, obj_link) {
> -		if (!list_empty(&vma->vm_link))
> -			list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
> -	}
> +	if (!list_empty(&obj->vma_list))
> +		list_move_tail(&obj->global_list,
> +			       &request->i915->mm.bound_list);
>
>   	drm_gem_object_unreference(&obj->base);
>   }
> @@ -2567,7 +2563,19 @@ static int __i915_vma_unbind(struct i915_vma *vma, bool wait)
>   {
>   	struct drm_i915_gem_object *obj = vma->obj;
>   	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
> -	int ret;
> +	int ret, i;
> +
> +	/* First wait upon any activity as retiring the request may
> +	 * have side-effects such as unpinning or even unbinding this vma.
> +	 */
> +	if (vma->active && wait) {
> +		for (i = 0; i < ARRAY_SIZE(vma->last_read); i++) {
> +			ret = i915_wait_request(vma->last_read[i].request);
> +			if (ret)
> +				return ret;
> +		}
> +		RQ_BUG_ON(vma->active);
> +	}
>
>   	if (list_empty(&vma->obj_link))
>   		return 0;
> @@ -2582,12 +2590,6 @@ static int __i915_vma_unbind(struct i915_vma *vma, bool wait)
>
>   	BUG_ON(obj->pages == NULL);
>
> -	if (wait) {
> -		ret = i915_gem_object_wait_rendering(obj, false);
> -		if (ret)
> -			return ret;
> -	}
> -
>   	if (vma->is_ggtt && vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL) {
>   		i915_gem_object_finish_gtt(obj);
>
> @@ -3023,9 +3025,8 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
>
>   	/* And bump the LRU for this access */
>   	vma = i915_gem_obj_to_ggtt(obj);
> -	if (vma && drm_mm_node_allocated(&vma->node) && !obj->active)
> -		list_move_tail(&vma->vm_link,
> -			       &to_i915(obj->base.dev)->gtt.base.inactive_list);
> +	if (vma && drm_mm_node_allocated(&vma->node) && !vma->active)
> +		list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
>
>   	return 0;
>   }
> @@ -3874,6 +3875,7 @@ struct i915_vma *i915_gem_obj_to_ggtt_view(struct drm_i915_gem_object *obj,
>   void i915_gem_vma_destroy(struct i915_vma *vma)
>   {
>   	WARN_ON(vma->node.allocated);
> +	RQ_BUG_ON(vma->active);
>
>   	/* Keep the vma as a placeholder in the execbuffer reservation lists */
>   	if (!list_empty(&vma->exec_list))
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 6de8681bb64c..1d4378a4501e 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1099,6 +1099,8 @@ void i915_vma_move_to_active(struct i915_vma *vma,
>   		}
>   	}
>
> +	vma->active |= 1 << engine;
> +	i915_gem_request_mark_active(req, &vma->last_read[engine]);
>   	list_move_tail(&vma->vm_link, &vma->vm->active_list);
>   }
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 130ccefb2491..5505603f52af 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -3225,12 +3225,30 @@ void i915_gem_restore_gtt_mappings(struct drm_device *dev)
>   	i915_ggtt_flush(dev_priv);
>   }
>
> +static void
> +i915_vma_retire(struct drm_i915_gem_request_active *active,
> +		struct drm_i915_gem_request *rq)
> +{
> +	const unsigned engine = rq->engine->id;
> +	struct i915_vma *vma =
> +		container_of(active, struct i915_vma, last_read[engine]);
> +
> +	RQ_BUG_ON((vma->obj->active & (1 << engine)) == 0);
> +
> +	vma->active &= ~(1 << engine);
> +	if (vma->active)
> +		return;
> +
> +	list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
> +}
> +
>   static struct i915_vma *
>   __i915_gem_vma_create(struct drm_i915_gem_object *obj,
>   		      struct i915_address_space *vm,
>   		      const struct i915_ggtt_view *ggtt_view)
>   {
>   	struct i915_vma *vma;
> +	int i;
>
>   	if (WARN_ON(i915_is_ggtt(vm) != !!ggtt_view))
>   		return ERR_PTR(-EINVAL);
> @@ -3242,6 +3260,8 @@ __i915_gem_vma_create(struct drm_i915_gem_object *obj,
>   	INIT_LIST_HEAD(&vma->vm_link);
>   	INIT_LIST_HEAD(&vma->obj_link);
>   	INIT_LIST_HEAD(&vma->exec_list);
> +	for (i = 0; i < ARRAY_SIZE(vma->last_read); i++)
> +		init_request_active(&vma->last_read[i], i915_vma_retire);
>   	vma->vm = vm;
>   	vma->obj = obj;
>   	vma->is_ggtt = i915_is_ggtt(vm);
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 4e9553ace33f..c2f2c62ac88d 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -34,6 +34,8 @@
>   #ifndef __I915_GEM_GTT_H__
>   #define __I915_GEM_GTT_H__
>
> +#include "i915_gem_request.h"
> +
>   struct drm_i915_file_private;
>
>   typedef uint32_t gen6_pte_t;
> @@ -180,10 +182,13 @@ struct i915_vma {
>   	struct drm_i915_gem_object *obj;
>   	struct i915_address_space *vm;
>
> +	struct drm_i915_gem_request_active last_read[I915_NUM_RINGS];
> +
>   	/** Flags and address space this VMA is bound to */
>   #define GLOBAL_BIND	(1<<0)
>   #define LOCAL_BIND	(1<<1)
>   	unsigned int bound : 4;
> +	unsigned int active : I915_NUM_RINGS;
>   	bool is_ggtt : 1;
>
>   	/**
>
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx