memcg: update menuconfig help text

page_cgroup is now allocated at boot and memmap doesn't includes pointer
for page_cgroup.  Fix the menu help text.

Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/init/Kconfig b/init/Kconfig
index 44e9208..86b00c5 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -401,16 +401,20 @@ config CGROUP_MEM_RES_CTLR
        depends on CGROUPS && RESOURCE_COUNTERS
        select MM_OWNER
        help
-         Provides a memory resource controller that manages both page cache and
-         RSS memory.
+         Provides a memory resource controller that manages both anonymous
+         memory and page cache. (See Documentation/controllers/memory.txt)
 
          Note that setting this option increases fixed memory overhead
-         associated with each page of memory in the system by 4/8 bytes
-         and also increases cache misses because struct page on many 64bit
-         systems will not fit into a single cache line anymore.
+         associated with each page of memory in the system. By this,
+         20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
+         usage tracking struct at boot. Total amount of this is printed out
+         at boot.
 
          Only enable when you're ok with these trade offs and really
-         sure you need the memory resource controller.
+         sure you need the memory resource controller. Even when you enable
+         this, you can set "cgroup_disable=memory" at your boot option to
+         disable memory resource controller and you can avoid overheads.
+         (and lose benefits of memory resource contoller)
 
          This config option also selects MM_OWNER config option, which
          could in turn add some fork/exit overhead.