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Commit 8a2421bd authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Wait upon userptr get-user-pages within execbuffer 



This simply hides the EAGAIN caused by userptr when userspace causes
resource contention. However, it is quite beneficial with highly
contended userptr users as we avoid repeating the setup costs and
kernel-user context switches.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMichał Winiarski <michal.winiarski@intel.com>
parent 616d9cee

drivers/gpu/drm/i915/i915_drv.c

+1 −0
Original line number Diff line number Diff line
@@ -579,6 +579,7 @@ static void i915_gem_fini(struct drm_i915_private *dev_priv) 
	intel_uc_fini_hw(dev_priv);

	i915_gem_cleanup_engines(dev_priv);

	i915_gem_context_fini(dev_priv);

	i915_gem_cleanup_userptr(dev_priv);

	mutex_unlock(&dev_priv->drm.struct_mutex);



	i915_gem_drain_freed_objects(dev_priv);

drivers/gpu/drm/i915/i915_drv.h

+9 −1
Original line number Diff line number Diff line
@@ -1453,6 +1453,13 @@ struct i915_gem_mm { 
	/** LRU list of objects with fence regs on them. */

	struct list_head fence_list;



	/**

	 * Workqueue to fault in userptr pages, flushed by the execbuf

	 * when required but otherwise left to userspace to try again

	 * on EAGAIN.

	 */

	struct workqueue_struct *userptr_wq;



	u64 unordered_timeline;



	/* the indicator for dispatch video commands on two BSD rings */
@@ -3228,7 +3235,8 @@ int i915_gem_set_tiling_ioctl(struct drm_device *dev, void *data, 
			      struct drm_file *file_priv);

int i915_gem_get_tiling_ioctl(struct drm_device *dev, void *data,

			      struct drm_file *file_priv);

void i915_gem_init_userptr(struct drm_i915_private *dev_priv);

int i915_gem_init_userptr(struct drm_i915_private *dev_priv);

void i915_gem_cleanup_userptr(struct drm_i915_private *dev_priv);

int i915_gem_userptr_ioctl(struct drm_device *dev, void *data,

			   struct drm_file *file);

int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,

drivers/gpu/drm/i915/i915_gem.c

+3 −1
Original line number Diff line number Diff line
@@ -4804,7 +4804,9 @@ int i915_gem_init(struct drm_i915_private *dev_priv) 
	 */

	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);



	i915_gem_init_userptr(dev_priv);

	ret = i915_gem_init_userptr(dev_priv);

	if (ret)

		goto out_unlock;



	ret = i915_gem_init_ggtt(dev_priv);

	if (ret)

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+3 −0
Original line number Diff line number Diff line
@@ -1499,6 +1499,9 @@ static noinline int eb_relocate_slow(struct i915_execbuffer *eb) 
		goto out;

	}



	/* A frequent cause for EAGAIN are currently unavailable client pages */

	flush_workqueue(eb->i915->mm.userptr_wq);



	err = i915_mutex_lock_interruptible(dev);

	if (err) {

		mutex_lock(&dev->struct_mutex);

drivers/gpu/drm/i915/i915_gem_userptr.c

+15 −3
Original line number Diff line number Diff line
@@ -378,7 +378,7 @@ __i915_mm_struct_free(struct kref *kref) 
	mutex_unlock(&mm->i915->mm_lock);



	INIT_WORK(&mm->work, __i915_mm_struct_free__worker);

	schedule_work(&mm->work);

	queue_work(mm->i915->mm.userptr_wq, &mm->work);

}



static void
@@ -598,7 +598,7 @@ __i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj) 
	get_task_struct(work->task);



	INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);

	schedule_work(&work->work);

	queue_work(to_i915(obj->base.dev)->mm.userptr_wq, &work->work);



	return ERR_PTR(-EAGAIN);

}
@@ -830,8 +830,20 @@ i915_gem_userptr_ioctl(struct drm_device *dev, void *data, struct drm_file *file 
	return 0;

}



void i915_gem_init_userptr(struct drm_i915_private *dev_priv)

int i915_gem_init_userptr(struct drm_i915_private *dev_priv)

{

	mutex_init(&dev_priv->mm_lock);

	hash_init(dev_priv->mm_structs);



	dev_priv->mm.userptr_wq =

		alloc_workqueue("i915-userptr-acquire", WQ_HIGHPRI, 0);

	if (!dev_priv->mm.userptr_wq)

		return -ENOMEM;



	return 0;

}



void i915_gem_cleanup_userptr(struct drm_i915_private *dev_priv)

{

	destroy_workqueue(dev_priv->mm.userptr_wq);

}