mm: simplify lock_page_memcg()

[karo-tx-linux.git] / include / linux / memcontrol.h

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 8502fd4144eb17066ed5c68a55c005e04f8d28bd..d560c9a3cadf2d438afc08452932a68b1dfc83f2 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -89,6 +89,10 @@ enum mem_cgroup_events_target {
 };
 
 #ifdef CONFIG_MEMCG
+
+#define MEM_CGROUP_ID_SHIFT    16
+#define MEM_CGROUP_ID_MAX      USHRT_MAX
+
 struct mem_cgroup_stat_cpu {
        long count[MEMCG_NR_STAT];
        unsigned long events[MEMCG_NR_EVENTS];
@@ -265,6 +269,11 @@ struct mem_cgroup {
 
 extern struct mem_cgroup *root_mem_cgroup;
 
+static inline bool mem_cgroup_disabled(void)
+{
+       return !cgroup_subsys_enabled(memory_cgrp_subsys);
+}
+
 /**
  * mem_cgroup_events - count memory events against a cgroup
  * @memcg: the memory cgroup
@@ -291,7 +300,7 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
 void mem_cgroup_uncharge(struct page *page);
 void mem_cgroup_uncharge_list(struct list_head *page_list);
 
-void mem_cgroup_replace_page(struct page *oldpage, struct page *newpage);
+void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
 
 struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
@@ -312,6 +321,28 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
                                   struct mem_cgroup_reclaim_cookie *);
 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
 
+static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
+{
+       if (mem_cgroup_disabled())
+               return 0;
+
+       return memcg->css.id;
+}
+
+/**
+ * mem_cgroup_from_id - look up a memcg from an id
+ * @id: the id to look up
+ *
+ * Caller must hold rcu_read_lock() and use css_tryget() as necessary.
+ */
+static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
+{
+       struct cgroup_subsys_state *css;
+
+       css = css_from_id(id, &memory_cgrp_subsys);
+       return mem_cgroup_from_css(css);
+}
+
 /**
  * parent_mem_cgroup - find the accounting parent of a memcg
  * @memcg: memcg whose parent to find
@@ -353,11 +384,6 @@ static inline bool mm_match_cgroup(struct mm_struct *mm,
 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);
 ino_t page_cgroup_ino(struct page *page);
 
-static inline bool mem_cgroup_disabled(void)
-{
-       return !cgroup_subsys_enabled(memory_cgrp_subsys);
-}
-
 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
 {
        if (mem_cgroup_disabled())
@@ -429,42 +455,42 @@ bool mem_cgroup_oom_synchronize(bool wait);
 extern int do_swap_account;
 #endif
 
-struct mem_cgroup *lock_page_memcg(struct page *page);
-void unlock_page_memcg(struct mem_cgroup *memcg);
+void lock_page_memcg(struct page *page);
+void unlock_page_memcg(struct page *page);
 
 /**
  * mem_cgroup_update_page_stat - update page state statistics
- * @memcg: memcg to account against
+ * @page: the page
  * @idx: page state item to account
  * @val: number of pages (positive or negative)
  *
  * Callers must use lock_page_memcg() to prevent double accounting
  * when the page is concurrently being moved to another memcg:
  *
- *   memcg = lock_page_memcg(page);
+ *   lock_page_memcg(page);
  *   if (TestClearPageState(page))
- *     mem_cgroup_update_page_stat(memcg, state, -1);
- *   unlock_page_memcg(memcg);
+ *     mem_cgroup_update_page_stat(page, state, -1);
+ *   unlock_page_memcg(page);
  */
-static inline void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
+static inline void mem_cgroup_update_page_stat(struct page *page,
                                 enum mem_cgroup_stat_index idx, int val)
 {
        VM_BUG_ON(!rcu_read_lock_held());
 
-       if (memcg)
-               this_cpu_add(memcg->stat->count[idx], val);
+       if (page->mem_cgroup)
+               this_cpu_add(page->mem_cgroup->stat->count[idx], val);
 }
 
-static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
+static inline void mem_cgroup_inc_page_stat(struct page *page,
                                            enum mem_cgroup_stat_index idx)
 {
-       mem_cgroup_update_page_stat(memcg, idx, 1);
+       mem_cgroup_update_page_stat(page, idx, 1);
 }
 
-static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
+static inline void mem_cgroup_dec_page_stat(struct page *page,
                                            enum mem_cgroup_stat_index idx)
 {
-       mem_cgroup_update_page_stat(memcg, idx, -1);
+       mem_cgroup_update_page_stat(page, idx, -1);
 }
 
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
@@ -502,8 +528,17 @@ void mem_cgroup_split_huge_fixup(struct page *head);
 #endif
 
 #else /* CONFIG_MEMCG */
+
+#define MEM_CGROUP_ID_SHIFT    0
+#define MEM_CGROUP_ID_MAX      0
+
 struct mem_cgroup;
 
+static inline bool mem_cgroup_disabled(void)
+{
+       return true;
+}
+
 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
                                     enum mem_cgroup_events_index idx,
                                     unsigned int nr)
@@ -545,7 +580,7 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
 {
 }
 
-static inline void mem_cgroup_replace_page(struct page *old, struct page *new)
+static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 {
 }
 
@@ -586,9 +621,16 @@ static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 {
 }
 
-static inline bool mem_cgroup_disabled(void)
+static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 {
-       return true;
+       return 0;
+}
+
+static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
+{
+       WARN_ON_ONCE(id);
+       /* XXX: This should always return root_mem_cgroup */
+       return NULL;
 }
 
 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
@@ -619,12 +661,11 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 {
 }
 
-static inline struct mem_cgroup *lock_page_memcg(struct page *page)
+static inline void lock_page_memcg(struct page *page)
 {
-       return NULL;
 }
 
-static inline void unlock_page_memcg(struct mem_cgroup *memcg)
+static inline void unlock_page_memcg(struct page *page)
 {
 }
 
@@ -650,12 +691,12 @@ static inline bool mem_cgroup_oom_synchronize(bool wait)
        return false;
 }
 
-static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
+static inline void mem_cgroup_inc_page_stat(struct page *page,
                                            enum mem_cgroup_stat_index idx)
 {
 }
 
-static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
+static inline void mem_cgroup_dec_page_stat(struct page *page,
                                            enum mem_cgroup_stat_index idx)
 {
 }