Beispiel #1
0
static void cancel_userptr(struct work_struct *work)
{
	struct i915_mmu_object *mo = container_of(work, typeof(*mo), work);
	struct drm_i915_gem_object *obj = mo->obj;
	struct work_struct *active;

	/* Cancel any active worker and force us to re-evaluate gup */
	mutex_lock(&obj->mm.lock);
	active = fetch_and_zero(&obj->userptr.work);
	mutex_unlock(&obj->mm.lock);
	if (active)
		goto out;

	i915_gem_object_wait(obj, I915_WAIT_ALL, MAX_SCHEDULE_TIMEOUT, NULL);

	mutex_lock(&obj->base.dev->struct_mutex);

	/* We are inside a kthread context and can't be interrupted */
	if (i915_gem_object_unbind(obj) == 0)
		__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
	WARN_ONCE(i915_gem_object_has_pages(obj),
		  "Failed to release pages: bind_count=%d, pages_pin_count=%d, pin_global=%d\n",
		  obj->bind_count,
		  atomic_read(&obj->mm.pages_pin_count),
		  obj->pin_global);

	mutex_unlock(&obj->base.dev->struct_mutex);

out:
	i915_gem_object_put(obj);
}
/**
 * i915_gem_shrink - Shrink buffer object caches
 * @dev_priv: i915 device
 * @target: amount of memory to make available, in pages
 * @nr_scanned: optional output for number of pages scanned (incremental)
 * @flags: control flags for selecting cache types
 *
 * This function is the main interface to the shrinker. It will try to release
 * up to @target pages of main memory backing storage from buffer objects.
 * Selection of the specific caches can be done with @flags. This is e.g. useful
 * when purgeable objects should be removed from caches preferentially.
 *
 * Note that it's not guaranteed that released amount is actually available as
 * free system memory - the pages might still be in-used to due to other reasons
 * (like cpu mmaps) or the mm core has reused them before we could grab them.
 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
 *
 * Also note that any kind of pinning (both per-vma address space pins and
 * backing storage pins at the buffer object level) result in the shrinker code
 * having to skip the object.
 *
 * Returns:
 * The number of pages of backing storage actually released.
 */
unsigned long
i915_gem_shrink(struct drm_i915_private *dev_priv,
		unsigned long target,
		unsigned long *nr_scanned,
		unsigned flags)
{
	const struct {
		struct list_head *list;
		unsigned int bit;
	} phases[] = {
		{ &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
		{ &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
		{ NULL, 0 },
	}, *phase;
	unsigned long count = 0;
	unsigned long scanned = 0;
	bool unlock;

	if (!shrinker_lock(dev_priv, &unlock))
		return 0;

	/*
	 * When shrinking the active list, also consider active contexts.
	 * Active contexts are pinned until they are retired, and so can
	 * not be simply unbound to retire and unpin their pages. To shrink
	 * the contexts, we must wait until the gpu is idle.
	 *
	 * We don't care about errors here; if we cannot wait upon the GPU,
	 * we will free as much as we can and hope to get a second chance.
	 */
	if (flags & I915_SHRINK_ACTIVE)
		i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);

	trace_i915_gem_shrink(dev_priv, target, flags);
	i915_gem_retire_requests(dev_priv);

	/*
	 * Unbinding of objects will require HW access; Let us not wake the
	 * device just to recover a little memory. If absolutely necessary,
	 * we will force the wake during oom-notifier.
	 */
	if ((flags & I915_SHRINK_BOUND) &&
	    !intel_runtime_pm_get_if_in_use(dev_priv))
		flags &= ~I915_SHRINK_BOUND;

	/*
	 * As we may completely rewrite the (un)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.
	 *
	 * In particular, we must hold a reference whilst removing the
	 * object as we may end up waiting for and/or retiring the objects.
	 * This might release the final reference (held by the active list)
	 * and result in the object being freed from under us. This is
	 * similar to the precautions the eviction code must take whilst
	 * removing objects.
	 *
	 * Also note that although these lists do not 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.
	 */
	for (phase = phases; phase->list; phase++) {
		struct list_head still_in_list;
		struct drm_i915_gem_object *obj;

		if ((flags & phase->bit) == 0)
			continue;

		INIT_LIST_HEAD(&still_in_list);

		/*
		 * We serialize our access to unreferenced objects through
		 * the use of the struct_mutex. While the objects are not
		 * yet freed (due to RCU then a workqueue) we still want
		 * to be able to shrink their pages, so they remain on
		 * the unbound/bound list until actually freed.
		 */
		spin_lock(&dev_priv->mm.obj_lock);
		while (count < target &&
		       (obj = list_first_entry_or_null(phase->list,
						       typeof(*obj),
						       mm.link))) {
			list_move_tail(&obj->mm.link, &still_in_list);

			if (flags & I915_SHRINK_PURGEABLE &&
			    obj->mm.madv != I915_MADV_DONTNEED)
				continue;

			if (flags & I915_SHRINK_VMAPS &&
			    !is_vmalloc_addr(obj->mm.mapping))
				continue;

			if (!(flags & I915_SHRINK_ACTIVE) &&
			    (i915_gem_object_is_active(obj) ||
			     i915_gem_object_is_framebuffer(obj)))
				continue;

			if (!can_release_pages(obj))
				continue;

			spin_unlock(&dev_priv->mm.obj_lock);

			if (unsafe_drop_pages(obj)) {
				/* May arrive from get_pages on another bo */
				mutex_lock_nested(&obj->mm.lock,
						  I915_MM_SHRINKER);
				if (!i915_gem_object_has_pages(obj)) {
					__i915_gem_object_invalidate(obj);
					count += obj->base.size >> PAGE_SHIFT;
				}
				mutex_unlock(&obj->mm.lock);
			}
			scanned += obj->base.size >> PAGE_SHIFT;

			spin_lock(&dev_priv->mm.obj_lock);
		}
		list_splice_tail(&still_in_list, phase->list);
		spin_unlock(&dev_priv->mm.obj_lock);
	}
static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
{
	if (i915_gem_object_unbind(obj) == 0)
		__i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
	return !i915_gem_object_has_pages(obj);
}
static void __i915_do_clflush(struct drm_i915_gem_object *obj)
{
	GEM_BUG_ON(!i915_gem_object_has_pages(obj));
	drm_clflush_sg(obj->mm.pages);
	intel_fb_obj_flush(obj, ORIGIN_CPU);
}