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Commit f8a7fde4 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Defer active reference until required 



We only need the active reference to keep the object alive after the
handle has been deleted (so as to prevent a synchronous gem_close). Why
then pay the price of a kref on every execbuf when we can insert that
final active ref just in time for the handle deletion?

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-6-chris@chris-wilson.co.uk
parent 2e36991a

drivers/gpu/drm/i915/i915_drv.h

+28 −0
Original line number Diff line number Diff line
@@ -2246,6 +2246,12 @@ struct drm_i915_gem_object { 
#define __I915_BO_ACTIVE(bo) \

	((READ_ONCE((bo)->flags) >> I915_BO_ACTIVE_SHIFT) & I915_BO_ACTIVE_MASK)



	/**

	 * Have we taken a reference for the object for incomplete GPU

	 * activity?

	 */

#define I915_BO_ACTIVE_REF (I915_BO_ACTIVE_SHIFT + I915_NUM_ENGINES)



	/**

	 * This is set if the object has been written to since last bound

	 * to the GTT
@@ -2407,6 +2413,28 @@ i915_gem_object_has_active_engine(const struct drm_i915_gem_object *obj, 
	return obj->flags & BIT(engine + I915_BO_ACTIVE_SHIFT);

}



static inline bool

i915_gem_object_has_active_reference(const struct drm_i915_gem_object *obj)

{

	return test_bit(I915_BO_ACTIVE_REF, &obj->flags);

}



static inline void

i915_gem_object_set_active_reference(struct drm_i915_gem_object *obj)

{

	lockdep_assert_held(&obj->base.dev->struct_mutex);

	__set_bit(I915_BO_ACTIVE_REF, &obj->flags);

}



static inline void

i915_gem_object_clear_active_reference(struct drm_i915_gem_object *obj)

{

	lockdep_assert_held(&obj->base.dev->struct_mutex);

	__clear_bit(I915_BO_ACTIVE_REF, &obj->flags);

}



void __i915_gem_object_release_unless_active(struct drm_i915_gem_object *obj);



static inline unsigned int

i915_gem_object_get_tiling(struct drm_i915_gem_object *obj)

{

drivers/gpu/drm/i915/i915_gem.c

+21 −1
Original line number Diff line number Diff line
@@ -2661,8 +2661,11 @@ i915_gem_object_retire__read(struct i915_gem_active *active, 
		list_move_tail(&obj->global_list,

			       &request->i915->mm.bound_list);



	if (i915_gem_object_has_active_reference(obj)) {

		i915_gem_object_clear_active_reference(obj);

		i915_gem_object_put(obj);

	}

}



static bool i915_context_is_banned(const struct i915_gem_context *ctx)

{
@@ -2935,6 +2938,12 @@ void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file) 
	list_for_each_entry_safe(vma, vn, &obj->vma_list, obj_link)

		if (vma->vm->file == fpriv)

			i915_vma_close(vma);



	if (i915_gem_object_is_active(obj) &&

	    !i915_gem_object_has_active_reference(obj)) {

		i915_gem_object_set_active_reference(obj);

		i915_gem_object_get(obj);

	}

	mutex_unlock(&obj->base.dev->struct_mutex);

}
@@ -4475,6 +4484,17 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj) 
	intel_runtime_pm_put(dev_priv);

}



void __i915_gem_object_release_unless_active(struct drm_i915_gem_object *obj)

{

	lockdep_assert_held(&obj->base.dev->struct_mutex);



	GEM_BUG_ON(i915_gem_object_has_active_reference(obj));

	if (i915_gem_object_is_active(obj))

		i915_gem_object_set_active_reference(obj);

	else

		i915_gem_object_put(obj);

}



int i915_gem_suspend(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = to_i915(dev);

drivers/gpu/drm/i915/i915_gem_batch_pool.c

+1 −1
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool) 
		list_for_each_entry_safe(obj, next,

					 &pool->cache_list[n],

					 batch_pool_link)

			i915_gem_object_put(obj);

			__i915_gem_object_release_unless_active(obj);



		INIT_LIST_HEAD(&pool->cache_list[n]);

	}

drivers/gpu/drm/i915/i915_gem_context.c

+1 −1
Original line number Diff line number Diff line
@@ -155,7 +155,7 @@ void i915_gem_context_free(struct kref *ctx_ref) 
		if (ce->ring)

			intel_ring_free(ce->ring);



		i915_vma_put(ce->state);

		__i915_gem_object_release_unless_active(ce->state->obj);

	}



	put_pid(ctx->pid);

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+0 −2
Original line number Diff line number Diff line
@@ -1290,8 +1290,6 @@ void i915_vma_move_to_active(struct i915_vma *vma, 
	 * add the active reference first and queue for it to be dropped

	 * *last*.

	 */

	if (!i915_gem_object_is_active(obj))

		i915_gem_object_get(obj);

	i915_gem_object_set_active(obj, idx);

	i915_gem_active_set(&obj->last_read[idx], req);