On Wed, Jul 15, 2015 at 08:25:23PM +0530, Goel, Akash wrote:
> >>+int
> >>+i915_gem_evict_for_vma(struct i915_vma *target)
> >>+{
> >>+ struct drm_mm_node *node, *next;
> >>+
> >>+ list_for_each_entry_safe(node, next,
> >>+ &target->vm->mm.head_node.node_list,
> >>+ node_list) {
> >>+ struct i915_vma *vma;
> >>+ int ret;
> >>+
> >>+ if (node->start + node->size <= target->node.start)
> >>+ continue;
> >>+ if (node->start >= target->node.start + target->node.size)
> >>+ break;
> >>+
> >>+ vma = container_of(node, typeof(*vma), node);
> >>+
> >>+ if (vma->pin_count) {
> >>+ /* We may need to evict a buffer in the same batch */
> >>+ if (!vma->exec_entry)
> >>+ return -EBUSY;
> >>+
> >>+ if (vma->exec_entry->flags & EXEC_OBJECT_PINNED)
> >>+ /* Overlapping fixed objects in the same batch
> >>*/
> >>+ return -EINVAL;
> >>+
> >>+ return -ENOSPC;
>
> Can we actually hit this condition, considering the soft pinned
> objects are now on the front side of 'eb->vmas' list ?
> If we do encounter such a case, it probably means that the
> overlapping object is already pinned from some other path.
Note that softpinned objects are only first on the second pass through
the reservation.
> Is there a scope of an additional check here ?
> i.e. if (vma->pin_count) is > 1, this indicates that the object is
> not only pinned due to execbuffer, hence cannot be evicted, so
> -EBUSY can be straight away returned to User.
Consider this instead:
int
i915_gem_evict_for_vma(struct i915_vma *target, unsigned flags)
{
struct list_head eviction_list;
struct interval_tree_node *it;
u64 end = target->node.start + target->node.size;
struct drm_mm_node *node;
struct i915_vma *vma, *next;
int ret;
it = interval_tree_iter_first(&target->vm->mm.interval_tree,
target->node.start, end -1);
if (it == NULL)
return 0;
INIT_LIST_HEAD(&eviction_list);
node = container_of(it, typeof(*node), it);
list_for_each_entry_from(node,
&target->vm->mm.head_node.node_list,
node_list) {
if (node->start >= end)
break;
vma = container_of(node, typeof(*vma), node);
if (flags & PIN_NONBLOCK &&
(vma->pin_count || vma->active.request)) {
ret = -ENOSPC;
break;
}
if (vma->exec_entry &&
vma->exec_entry->flags & EXEC_OBJECT_PINNED) {
/* Overlapping pinned objects in the same batch */
ret = -EINVAL;
break;
}
if (vma->pin_count) {
/* We may need to evict an buffer in the same batch */
ret = vma->exec_entry ? -ENOSPC : -EBUSY;
break;
}
list_add(&vma->exec_list, &eviction_list);
drm_gem_object_reference(&vma->obj->base);
}
ret = 0;
list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
struct drm_i915_gem_object *obj = vma->obj;
if (ret == 0)
ret = i915_vma_unbind(vma);
drm_gem_object_unreference(&obj->base);
}
return ret;
}
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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