drm/ttm: Optimize ttm_eu_backoff_reservation

Avoid the ttm_bo_unreserve() spinlocks by calling
ttm_eu_backoff_reservation_locked under the lru spinlock.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jerome Glisse <j.glisse@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index 201a71d..7dcc647 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -101,15 +101,16 @@ static int ttm_eu_wait_unreserved_locked(struct list_head *list,
 void ttm_eu_backoff_reservation(struct list_head *list)
 {
        struct ttm_validate_buffer *entry;
+       struct ttm_bo_global *glob;
 
-       list_for_each_entry(entry, list, head) {
-               struct ttm_buffer_object *bo = entry->bo;
-               if (!entry->reserved)
-                       continue;
+       if (list_empty(list))
+               return;
 
-               entry->reserved = false;
-               ttm_bo_unreserve(bo);
-       }
+       entry = list_first_entry(list, struct ttm_validate_buffer, head);
+       glob = entry->bo->glob;
+       spin_lock(&glob->lru_lock);
+       ttm_eu_backoff_reservation_locked(list);
+       spin_unlock(&glob->lru_lock);
 }
 EXPORT_SYMBOL(ttm_eu_backoff_reservation);