diff options
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem.c | 45 |
1 files changed, 39 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index f21a0c36a40b..d9e337feef14 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1695,6 +1695,7 @@ static long __i915_gem_shrink(struct drm_i915_private *dev_priv, long target, bool purgeable_only) { + struct list_head still_bound_list; struct drm_i915_gem_object *obj, *next; long count = 0; @@ -1709,23 +1710,55 @@ __i915_gem_shrink(struct drm_i915_private *dev_priv, long target, } } - list_for_each_entry_safe(obj, next, &dev_priv->mm.bound_list, - global_list) { + /* + * As we may completely rewrite the bound list whilst unbinding + * (due to retiring requests) we have to strictly process only + * one element of the list at the time, and recheck the list + * on every iteration. + */ + INIT_LIST_HEAD(&still_bound_list); + while (count < target && !list_empty(&dev_priv->mm.bound_list)) { struct i915_vma *vma, *v; + obj = list_first_entry(&dev_priv->mm.bound_list, + typeof(*obj), global_list); + list_move_tail(&obj->global_list, &still_bound_list); + if (!i915_gem_object_is_purgeable(obj) && purgeable_only) continue; + /* + * Hold a reference whilst we unbind this object, as we may + * end up waiting for and retiring requests. This might + * release the final reference (held by the active list) + * and result in the object being freed from under us. + * in this object being freed. + * + * Note 1: Shrinking the bound list is special since only active + * (and hence bound objects) can contain such limbo objects, so + * we don't need special tricks for shrinking the unbound list. + * The only other place where we have to be careful with active + * objects suddenly disappearing due to retiring requests is the + * eviction code. + * + * Note 2: Even though the bound list doesn't hold a reference + * to the object we can safely grab one here: The final object + * unreferencing and the bound_list are both protected by the + * dev->struct_mutex and so we won't ever be able to observe an + * object on the bound_list with a reference count equals 0. + */ + drm_gem_object_reference(&obj->base); + list_for_each_entry_safe(vma, v, &obj->vma_list, vma_link) if (i915_vma_unbind(vma)) break; - if (!i915_gem_object_put_pages(obj)) { + if (i915_gem_object_put_pages(obj) == 0) count += obj->base.size >> PAGE_SHIFT; - if (count >= target) - return count; - } + + drm_gem_object_unreference(&obj->base); } + list_splice(&still_bound_list, &dev_priv->mm.bound_list); return count; } |