From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
This patch add support for cgroup removal. If we don't have parent
cgroup, the charges are moved to root cgroup.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
mm/hugetlb_cgroup.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 79 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 48efd5a..9458fe3 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -99,10 +99,87 @@ static void hugetlb_cgroup_destroy(struct cgroup *cgroup)
kfree(h_cgroup);
}
+
+static int 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);
+
+ if (!get_page_unless_zero(page))
+ goto out;
+
+ 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 err_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);
+err_out:
+ put_page(page);
+out:
+ return 0;
+}
+
+/*
+ * 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)
{
- /* We will add the cgroup removal support in later patches */
- return -EBUSY;
+ struct hstate *h;
+ struct page *page;
+ int ret = 0, idx = 0;
+
+ do {
+ if (cgroup_task_count(cgroup) ||
+ !list_empty(&cgroup->children)) {
+ ret = -EBUSY;
+ goto out;
+ }
+ /*
+ * If the task doing the cgroup_rmdir got a signal
+ * we don't really need to loop till the hugetlb resource
+ * usage become zero.
+ */
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ goto out;
+ }
+ for_each_hstate(h) {
+ spin_lock(&hugetlb_lock);
+ list_for_each_entry(page, &h->hugepage_activelist, lru) {
+ ret = hugetlb_cgroup_move_parent(idx, cgroup, page);
+ if (ret) {
+ spin_unlock(&hugetlb_lock);
+ goto out;
+ }
+ }
+ spin_unlock(&hugetlb_lock);
+ idx++;
+ }
+ cond_resched();
+ } while (hugetlb_cgroup_have_usage(cgroup));
+out:
+ return ret;
}
int hugetlb_cgroup_charge_page(int idx, unsigned long nr_pages,
--
1.7.10
--
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