Merge "add documentation about reclaim knob on proc.txt"

Documentation/filesystems/proc.txt

@@ -139,6 +139,7 @@ Table 1-1: Process specific entries in /proc
  maps		Memory maps to executables and library files	(2.4)
  mem		Memory held by this process
  root		Link to the root directory of this process
+ reclaim	Reclaim pages in this process
  stat		Process status
  statm		Process memory status information
  status		Process status in human readable form
@@ -543,6 +544,25 @@ current value:
 
 Any other value written to /proc/PID/clear_refs will have no effect.
 
+The file /proc/PID/reclaim is used to reclaim pages in this process.
+To reclaim file-backed pages,
+    > echo file > /proc/PID/reclaim
+
+To reclaim anonymous pages,
+    > echo anon > /proc/PID/reclaim
+
+To reclaim all pages,
+    > echo all > /proc/PID/reclaim
+
+Also, you can specify address range of process so part of address space
+will be reclaimed. The format is following as
+    > echo addr size-byte > /proc/PID/reclaim
+
+NOTE: addr should be page-aligned.
+
+Below is example which try to reclaim 2M from 0x100000.
+    > echo 0x100000 2M > /proc/PID/reclaim
+
 The /proc/pid/pagemap gives the PFN, which can be used to find the pageflags
 using /proc/kpageflags and number of times a page is mapped using
 /proc/kpagecount. For detailed explanation, see