1 files changed, 103 insertions, 0 deletions
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
new file mode 100644
index 000000000000..0fd39f2231ec
--- /dev/null
+++ b/include/linux/page_cgroup.h
@@ -0,0 +1,103 @@
+#ifndef __LINUX_PAGE_CGROUP_H
+#define __LINUX_PAGE_CGROUP_H
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+#include <linux/bit_spinlock.h>
+/*
+ * Page Cgroup can be considered as an extended mem_map.
+ * A page_cgroup page is associated with every page descriptor. The
+ * page_cgroup helps us identify information about the cgroup
+ * All page cgroups are allocated at boot or memory hotplug event,
+ * then the page cgroup for pfn always exists.
+ */
+struct page_cgroup {
+	unsigned long flags;
+	struct mem_cgroup *mem_cgroup;
+	struct page *page;
+	struct list_head lru;		/* per cgroup LRU list */
+};
+
+void __init pgdat_page_cgroup_init(struct pglist_data *pgdat);
+void __init page_cgroup_init(void);
+struct page_cgroup *lookup_page_cgroup(struct page *page);
+
+enum {
+	/* flags for mem_cgroup */
+	PCG_LOCK,  /* page cgroup is locked */
+	PCG_CACHE, /* charged as cache */
+	PCG_USED, /* this object is in use. */
+	/* flags for LRU placement */
+	PCG_ACTIVE, /* page is active in this cgroup */
+	PCG_FILE, /* page is file system backed */
+	PCG_UNEVICTABLE, /* page is unevictableable */
+};
+
+#define TESTPCGFLAG(uname, lname)			\
+static inline int PageCgroup##uname(struct page_cgroup *pc)	\
+	{ return test_bit(PCG_##lname, &pc->flags); }
+
+#define SETPCGFLAG(uname, lname)			\
+static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
+	{ set_bit(PCG_##lname, &pc->flags);  }
+
+#define CLEARPCGFLAG(uname, lname)			\
+static inline void ClearPageCgroup##uname(struct page_cgroup *pc)	\
+	{ clear_bit(PCG_##lname, &pc->flags);  }
+
+/* Cache flag is set only once (at allocation) */
+TESTPCGFLAG(Cache, CACHE)
+
+TESTPCGFLAG(Used, USED)
+CLEARPCGFLAG(Used, USED)
+
+/* LRU management flags (from global-lru definition) */
+TESTPCGFLAG(File, FILE)
+SETPCGFLAG(File, FILE)
+CLEARPCGFLAG(File, FILE)
+
+TESTPCGFLAG(Active, ACTIVE)
+SETPCGFLAG(Active, ACTIVE)
+CLEARPCGFLAG(Active, ACTIVE)
+
+TESTPCGFLAG(Unevictable, UNEVICTABLE)
+SETPCGFLAG(Unevictable, UNEVICTABLE)
+CLEARPCGFLAG(Unevictable, UNEVICTABLE)
+
+static inline int page_cgroup_nid(struct page_cgroup *pc)
+{
+	return page_to_nid(pc->page);
+}
+
+static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
+{
+	return page_zonenum(pc->page);
+}
+
+static inline void lock_page_cgroup(struct page_cgroup *pc)
+{
+	bit_spin_lock(PCG_LOCK, &pc->flags);
+}
+
+static inline int trylock_page_cgroup(struct page_cgroup *pc)
+{
+	return bit_spin_trylock(PCG_LOCK, &pc->flags);
+}
+
+static inline void unlock_page_cgroup(struct page_cgroup *pc)
+{
+	bit_spin_unlock(PCG_LOCK, &pc->flags);
+}
+
+#else /* CONFIG_CGROUP_MEM_RES_CTLR */
+struct page_cgroup;
+
+static inline void pgdat_page_cgroup_init(struct pglist_data *pgdat)
+{
+}
+
+static inline struct page_cgroup *lookup_page_cgroup(struct page *page)
+{
+	return NULL;
+}
+#endif
+#endif