[PATCH] NOMMU: Add docs about shared memory

Add documentation about using shared memory in NOMMU mode.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/nommu-mmap.txt

@@ -129,6 +129,15 @@ FURTHER NOTES ON NO-MMU MMAP
      with character device files, pipes, fifos and sockets.
 
 
+==========================
+INTERPROCESS SHARED MEMORY
+==========================
+
+Both SYSV IPC SHM shared memory and POSIX shared memory is supported in NOMMU
+mode.  The former through the usual mechanism, the latter through files created
+on ramfs or tmpfs mounts.
+
+
 =============
 NO-MMU MREMAP
 =============