mm: simplify lock_page_memcg()
Now that migration doesn't clear page->mem_cgroup of live pages anymore,
it's safe to make lock_page_memcg() and the memcg stat functions take
pages, and spare the callers from memcg objects.
[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c45ab3f..d560c9a 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -455,42 +455,42 @@
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,
@@ -661,12 +661,11 @@
{
}
-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)
{
}
@@ -692,12 +691,12 @@
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)
{
}