hugetlb/cgroup: add support for cgroup removal

	kfree(h_cgroup);

	kfree(h_cgroup);

}

}

/*

 * Should be called with hugetlb_lock held.

 * Since we are holding hugetlb_lock, pages cannot get moved from

 * active list or uncharged from the cgroup, So no need to get

 * page reference and test for page active here. This function

 * cannot fail.

 */

static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,

				       struct page *page)

{

	int csize;

	struct res_counter *counter;

	struct res_counter *fail_res;

	struct hugetlb_cgroup *page_hcg;

	struct hugetlb_cgroup *h_cg   = hugetlb_cgroup_from_cgroup(cgroup);

	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);

	page_hcg = hugetlb_cgroup_from_page(page);

	/*

	 * We can have pages in active list without any cgroup

	 * ie, hugepage with less than 3 pages. We can safely

	 * ignore those pages.

	 */

	if (!page_hcg || page_hcg != h_cg)

		goto out;

	csize = PAGE_SIZE << compound_order(page);

	if (!parent) {

		parent = root_h_cgroup;

		/* root has no limit */

		res_counter_charge_nofail(&parent->hugepage[idx],

					  csize, &fail_res);

	}

	counter = &h_cg->hugepage[idx];

	res_counter_uncharge_until(counter, counter->parent, csize);

	set_hugetlb_cgroup(page, parent);

out:

	return;

}

/*

 * Force the hugetlb cgroup to empty the hugetlb resources by moving them to

 * the parent cgroup.

 */

static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)

static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)

{

{

	/* We will add the cgroup removal support in later patches */

	struct hstate *h;

	   return -EBUSY;

	struct page *page;

	int ret = 0, idx = 0;

	do {

		if (cgroup_task_count(cgroup) ||

		    !list_empty(&cgroup->children)) {

			ret = -EBUSY;

			goto out;

		}

		for_each_hstate(h) {

			spin_lock(&hugetlb_lock);

			list_for_each_entry(page, &h->hugepage_activelist, lru)

				hugetlb_cgroup_move_parent(idx, cgroup, page);

			spin_unlock(&hugetlb_lock);

			idx++;

		}

		cond_resched();

	} while (hugetlb_cgroup_have_usage(cgroup));

out:

	return ret;

}

}

int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,

int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,