hugetlb/cgroup: add the cgroup pointer to page lru

Add the hugetlb cgroup pointer to 3rd page lru.next.  This limit the usage
to hugetlb cgroup to only hugepages with 3 or more normal pages.  I guess
that is an acceptable limitation.

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>
Reviewed-by: 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>

2 files changed, 41 insertions, 0 deletions

diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
index f19889e56b47..e5451a3b4ebc 100644
--- a/include/linux/hugetlb_cgroup.h
+++ b/include/linux/hugetlb_cgroup.h
@@ -18,8 +18,34 @@
 #include <linux/res_counter.h>
 
 struct hugetlb_cgroup;
+/*
+ * Minimum page order trackable by hugetlb cgroup.
+ * At least 3 pages are necessary for all the tracking information.
+ */
+#define HUGETLB_CGROUP_MIN_ORDER        2
 
 #ifdef CONFIG_CGROUP_HUGETLB
+
+static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
+{
+        VM_BUG_ON(!PageHuge(page));
+
+        if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
+                return NULL;
+        return (struct hugetlb_cgroup *)page[2].lru.next;
+}
+
+static inline
+int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
+{
+        VM_BUG_ON(!PageHuge(page));
+
+        if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER)
+                return -1;
+        page[2].lru.next = (void *)h_cg;
+        return 0;
+}
+
 static inline bool hugetlb_cgroup_disabled(void)
 {
         if (hugetlb_subsys.disabled)
@@ -28,6 +54,17 @@ static inline bool hugetlb_cgroup_disabled(void)
 }
 
 #else
+static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
+{
+        return NULL;
+}
+
+static inline
+int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
+{
+        return 0;
+}
+
 static inline bool hugetlb_cgroup_disabled(void)
 {
         return true;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d5971597736b..efe29b53daff 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -28,6 +28,7 @@
 
 #include <linux/io.h>
 #include <linux/hugetlb.h>
+#include <linux/hugetlb_cgroup.h>
 #include <linux/node.h>
 #include "internal.h"
 
@@ -591,6 +592,7 @@ static void update_and_free_page(struct hstate *h, struct page *page)
                                 1 << PG_active | 1 << PG_reserved |
                                 1 << PG_private | 1 << PG_writeback);
         }
+        VM_BUG_ON(hugetlb_cgroup_from_page(page));
         set_compound_page_dtor(page, NULL);
         set_page_refcounted(page);
         arch_release_hugepage(page);
@@ -643,6 +645,7 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
         INIT_LIST_HEAD(&page->lru);
         set_compound_page_dtor(page, free_huge_page);
         spin_lock(&hugetlb_lock);
+        set_hugetlb_cgroup(page, NULL);
         h->nr_huge_pages++;
         h->nr_huge_pages_node[nid]++;
         spin_unlock(&hugetlb_lock);
@@ -892,6 +895,7 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
                 INIT_LIST_HEAD(&page->lru);
                 r_nid = page_to_nid(page);
                 set_compound_page_dtor(page, free_huge_page);
+                set_hugetlb_cgroup(page, NULL);
                 /*
                  * We incremented the global counters already
                  */