hugetlb/cgroup: migrate hugetlb cgroup info from oldpage to new page during migration
With HugeTLB pages, hugetlb cgroup is uncharged in compound page
destructor. Since we are holding a hugepage reference, we can be sure
that old page won't get uncharged till the last put_page().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index d1ca119..680e481 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -386,6 +386,26 @@
return 0;
}
+void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
+{
+ struct hugetlb_cgroup *h_cg;
+
+ if (hugetlb_cgroup_disabled())
+ return;
+
+ VM_BUG_ON(!PageHuge(oldhpage));
+ 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);
+ spin_unlock(&hugetlb_lock);
+ cgroup_release_and_wakeup_rmdir(&h_cg->css);
+ return;
+}
+
struct cgroup_subsys hugetlb_subsys = {
.name = "hugetlb",
.create = hugetlb_cgroup_create,