memcg: remove MEMCG_NR_FILE_MAPPED

While accounting memcg page stat, it's not worth to use
MEMCG_NR_FILE_MAPPED as an extra layer of indirection because of the
complexity and presumed performance overhead.  We can use
MEM_CGROUP_STAT_FILE_MAPPED directly.

Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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 89d576c..f952a07 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -30,9 +30,20 @@ struct page;
 struct mm_struct;
 struct kmem_cache;
 
-/* Stats that can be updated by kernel. */
-enum mem_cgroup_page_stat_item {
-       MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
+/*
+ * The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
+ * These two lists should keep in accord with each other.
+ */
+enum mem_cgroup_stat_index {
+       /*
+        * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
+        */
+       MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
+       MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
+       MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
+       MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
+       MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
+       MEM_CGROUP_STAT_NSTATS,
 };
 
 struct mem_cgroup_reclaim_cookie {
@@ -233,17 +244,17 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page,
 }
 
 void mem_cgroup_update_page_stat(struct page *page,
-                                enum mem_cgroup_page_stat_item idx,
+                                enum mem_cgroup_stat_index idx,
                                 int val);
 
 static inline void mem_cgroup_inc_page_stat(struct page *page,
-                                           enum mem_cgroup_page_stat_item idx)
+                                           enum mem_cgroup_stat_index idx)
 {
        mem_cgroup_update_page_stat(page, idx, 1);
 }
 
 static inline void mem_cgroup_dec_page_stat(struct page *page,
-                                           enum mem_cgroup_page_stat_item idx)
+                                           enum mem_cgroup_stat_index idx)
 {
        mem_cgroup_update_page_stat(page, idx, -1);
 }
@@ -449,12 +460,12 @@ static inline bool mem_cgroup_oom_synchronize(void)
 }
 
 static inline void mem_cgroup_inc_page_stat(struct page *page,
-                                           enum mem_cgroup_page_stat_item idx)
+                                           enum mem_cgroup_stat_index idx)
 {
 }
 
 static inline void mem_cgroup_dec_page_stat(struct page *page,
-                                           enum mem_cgroup_page_stat_item idx)
+                                           enum mem_cgroup_stat_index idx)
 {
 }
 

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2c71f24..f380346 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -84,21 +84,6 @@ static int really_do_swap_account __initdata = 0;
 #endif
 
 
-/*
- * Statistics for memory cgroup.
- */
-enum mem_cgroup_stat_index {
-       /*
-        * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
-        */
-       MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
-       MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
-       MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
-       MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
-       MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
-       MEM_CGROUP_STAT_NSTATS,
-};
-
 static const char * const mem_cgroup_stat_names[] = {
        "cache",
        "rss",
@@ -2231,7 +2216,7 @@ void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
 }
 
 void mem_cgroup_update_page_stat(struct page *page,
-                                enum mem_cgroup_page_stat_item idx, int val)
+                                enum mem_cgroup_stat_index idx, int val)
 {
        struct mem_cgroup *memcg;
        struct page_cgroup *pc = lookup_page_cgroup(page);
@@ -2244,14 +2229,6 @@ void mem_cgroup_update_page_stat(struct page *page,
        if (unlikely(!memcg || !PageCgroupUsed(pc)))
                return;
 
-       switch (idx) {
-       case MEMCG_NR_FILE_MAPPED:
-               idx = MEM_CGROUP_STAT_FILE_MAPPED;
-               break;
-       default:
-               BUG();
-       }
-
        this_cpu_add(memcg->stat->count[idx], val);
 }
 

diff --git a/mm/rmap.c b/mm/rmap.c
index 07748e6..a21c976 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1111,7 +1111,7 @@ void page_add_file_rmap(struct page *page)
        mem_cgroup_begin_update_page_stat(page, &locked, &flags);
        if (atomic_inc_and_test(&page->_mapcount)) {
                __inc_zone_page_state(page, NR_FILE_MAPPED);
-               mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
+               mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
        }
        mem_cgroup_end_update_page_stat(page, &locked, &flags);
 }
@@ -1155,7 +1155,7 @@ void page_remove_rmap(struct page *page)
                                              NR_ANON_TRANSPARENT_HUGEPAGES);
        } else {
                __dec_zone_page_state(page, NR_FILE_MAPPED);
-               mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
+               mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
                mem_cgroup_end_update_page_stat(page, &locked, &flags);
        }
        if (unlikely(PageMlocked(page)))