hugetlb/cgroup: assign the page hugetlb cgroup when we move the page to active list.

A page's hugetlb cgroup assignment and movement to the active list should
occur with hugetlb_lock held.  Otherwise when we remove the hugetlb cgroup
we will iterate the active list and find pages with NULL hugetlb cgroup
values.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 680e4819e077..9834a01c79dc 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -213,6 +213,7 @@ 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 +221,7 @@ 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;
 }
 
@@ -389,6 +388,7 @@ int __init hugetlb_cgroup_file_init(int idx)
 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;
@@ -401,6 +401,7 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
 
         /* 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;