[PATCH v2] Document the new Anonymous field in smaps.

Nikanth Karthikesan
2010-09-17T06:01:14Z

Document the new Anonymous field in smaps.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>

---

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index a6aca87..b430576 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -370,17 +370,24 @@ Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 892 kB
+Anonymous: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB

-The first of these lines shows the same information as is displayed for the
-mapping in /proc/PID/maps. The remaining lines show the size of the mapping,
+The first of these lines shows the same information as is displayed for the
+mapping in /proc/PID/maps. The remaining lines show the size of the mapping,
the amount of the mapping that is currently resident in RAM, the "proportional
set size” (divide each shared page by the number of processes sharing it), the
number of clean and dirty shared pages in the mapping, and the number of clean
-and dirty private pages in the mapping. The "Referenced" indicates the amount
-of memory currently marked as referenced or accessed.
+and dirty private pages in the mapping. Even pages which are part of
+MAP_SHARED mappings, but has only a single pte mapped i.e., used exclusively
+by a process is accounted as private and not as shared. The "Referenced"
+indicates the amount of memory currently marked as referenced or accessed. The
+"Anonymous" shows the number of pages that is not associated with a file. Even
+mappings associated with a file can have anonymous pages. When the mapping is
+MAP_PRIVATE and its pages are modified, the pages are COWed and marked as
+anonymous.

This file is only present if the CONFIG_MMU kernel configuration option is
enabled.