1 files changed, 5 insertions, 2 deletions

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index c7de7dac43b5..4c95c0034a4b 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -410,8 +410,11 @@ memory.stat file includes following statistics
 cache           - # of bytes of page cache memory.
 rss             - # of bytes of anonymous and swap cache memory.
 mapped_file     - # of bytes of mapped file (includes tmpfs/shmem)
-pgpgin          - # of pages paged in (equivalent to # of charging events).
-pgpgout         - # of pages paged out (equivalent to # of uncharging events).
+pgpgin          - # of charging events to the memory cgroup. The charging
+                event happens each time a page is accounted as either mapped
+                anon page(RSS) or cache page(Page Cache) to the cgroup.
+pgpgout         - # of uncharging events to the memory cgroup. The uncharging
+                event happens each time a page is unaccounted from the cgroup.
 swap            - # of bytes of swap usage
 inactive_anon   - # of bytes of anonymous memory and swap cache memory on
                 LRU list.