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Commit 95762c2b authored by Thomas Hellstrom's avatar Thomas Hellstrom Committed by Dave Airlie
Browse files

drm/ttm: Improved fencing of buffer object lists 



Drastically reduce the number of spin lock / unlock operations by performing
unreserving and fencing under global locks.

Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: default avatarJerome Glisse <j.glisse@redhat.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 702adba2

drivers/gpu/drm/ttm/ttm_bo.c

+8 −3
Original line number Diff line number Diff line
@@ -299,14 +299,19 @@ int ttm_bo_reserve(struct ttm_buffer_object *bo, 
	return ret;

}



void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo)

{

	ttm_bo_add_to_lru(bo);

	atomic_set(&bo->reserved, 0);

	wake_up_all(&bo->event_queue);

}



void ttm_bo_unreserve(struct ttm_buffer_object *bo)

{

	struct ttm_bo_global *glob = bo->glob;



	spin_lock(&glob->lru_lock);

	ttm_bo_add_to_lru(bo);

	atomic_set(&bo->reserved, 0);

	wake_up_all(&bo->event_queue);

	ttm_bo_unreserve_locked(bo);

	spin_unlock(&glob->lru_lock);

}

EXPORT_SYMBOL(ttm_bo_unreserve);

drivers/gpu/drm/ttm/ttm_execbuf_util.c

+25 −11
Original line number Diff line number Diff line
@@ -200,22 +200,36 @@ EXPORT_SYMBOL(ttm_eu_reserve_buffers); 
void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)

{

	struct ttm_validate_buffer *entry;

	struct ttm_buffer_object *bo;

	struct ttm_bo_global *glob;

	struct ttm_bo_device *bdev;

	struct ttm_bo_driver *driver;



	list_for_each_entry(entry, list, head) {

		struct ttm_buffer_object *bo = entry->bo;

		struct ttm_bo_device *bdev = bo->bdev;

		struct ttm_bo_driver *driver = bdev->driver;

		void *old_sync_obj;

	if (list_empty(list))

		return;



	bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;

	bdev = bo->bdev;

	driver = bdev->driver;

	glob = bo->glob;



	spin_lock(&bdev->fence_lock);

		old_sync_obj = bo->sync_obj;

	spin_lock(&glob->lru_lock);



	list_for_each_entry(entry, list, head) {

		bo = entry->bo;

		entry->old_sync_obj = bo->sync_obj;

		bo->sync_obj = driver->sync_obj_ref(sync_obj);

		bo->sync_obj_arg = entry->new_sync_obj_arg;

		spin_unlock(&bdev->fence_lock);

		ttm_bo_unreserve(bo);

		ttm_bo_unreserve_locked(bo);

		entry->reserved = false;

		if (old_sync_obj)

			driver->sync_obj_unref(&old_sync_obj);

	}

	spin_unlock(&glob->lru_lock);

	spin_unlock(&bdev->fence_lock);



	list_for_each_entry(entry, list, head) {

		if (entry->old_sync_obj)

			driver->sync_obj_unref(&entry->old_sync_obj);

	}

}

EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);

include/drm/ttm/ttm_bo_driver.h

+10 −0
Original line number Diff line number Diff line
@@ -909,6 +909,16 @@ extern int ttm_bo_reserve_locked(struct ttm_buffer_object *bo, 
 */

extern void ttm_bo_unreserve(struct ttm_buffer_object *bo);



/**

 * ttm_bo_unreserve_locked

 *

 * @bo: A pointer to a struct ttm_buffer_object.

 *

 * Unreserve a previous reservation of @bo.

 * Needs to be called with struct ttm_bo_global::lru_lock held.

 */

extern void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo);



/**

 * ttm_bo_wait_unreserved

 *

include/drm/ttm/ttm_execbuf_util.h

+2 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
 * @reserved:       Indicates whether @bo has been reserved for validation.

 * @removed:        Indicates whether @bo has been removed from lru lists.

 * @put_count:      Number of outstanding references on bo::list_kref.

 * @old_sync_obj:   Pointer to a sync object about to be unreferenced

 */



struct ttm_validate_buffer {
@@ -53,6 +54,7 @@ struct ttm_validate_buffer { 
	bool reserved;

	bool removed;

	int put_count;

	void *old_sync_obj;

};



/**