hugetlb: do not fail in hugetlb_cgroup_pre_destroy

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / hugetlb_cgroup.c

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 680e481..dc595c6 100644 (file)
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -159,14 +159,9 @@ static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
 {
        struct hstate *h;
        struct page *page;
-       int ret = 0, idx = 0;
+       int 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)
@@ -177,8 +172,8 @@ static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
                }
                cond_resched();
        } while (hugetlb_cgroup_have_usage(cgroup));
-out:
-       return ret;
+
+       return 0;
 }
 
 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
@@ -213,6 +208,7 @@ done:
        return ret;
 }
 
+/* Should be called with hugetlb_lock held */
 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
                                  struct hugetlb_cgroup *h_cg,
                                  struct page *page)
@@ -220,9 +216,7 @@ void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
        if (hugetlb_cgroup_disabled() || !h_cg)
                return;
 
-       spin_lock(&hugetlb_lock);
        set_hugetlb_cgroup(page, h_cg);
-       spin_unlock(&hugetlb_lock);
        return;
 }
 
@@ -386,9 +380,14 @@ int __init hugetlb_cgroup_file_init(int idx)
        return 0;
 }
 
+/*
+ * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
+ * when we migrate hugepages
+ */
 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
 {
        struct hugetlb_cgroup *h_cg;
+       struct hstate *h = page_hstate(oldhpage);
 
        if (hugetlb_cgroup_disabled())
                return;
@@ -397,12 +396,11 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
        spin_lock(&hugetlb_lock);
        h_cg = hugetlb_cgroup_from_page(oldhpage);
        set_hugetlb_cgroup(oldhpage, NULL);
-       cgroup_exclude_rmdir(&h_cg->css);
 
        /* move the h_cg details to new cgroup */
        set_hugetlb_cgroup(newhpage, h_cg);
+       list_move(&newhpage->lru, &h->hugepage_activelist);
        spin_unlock(&hugetlb_lock);
-       cgroup_release_and_wakeup_rmdir(&h_cg->css);
        return;
 }