Document on-demand paging configuration settings

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2858 42af7a65-404d-4744-a932-0658087f49c3

Documentation/NuttxPortingGuide.html

@@ -2375,6 +2375,46 @@ extern void up_ledoff(int led);
   </li>
 </ul>
 
+<p>
+ OS setup related to on-demand paging:
+</p>
+<ul>
+  <li>
+    <code>CONFIG_PAGING</code>: If set =y in your configation file, this setting will
+          enable the on-demand paging feature as described in
+          <a href="http://www.nuttx.org/NuttXDemandPaging.html">http://www.nuttx.org/NuttXDemandPaging.html</a>.
+  </li>
+</ul>
+
+<p>
+  If CONFIG_PAGING is selected, then the following also apply:
+</p>
+<ul>
+  <li>
+    <code>CONFIG_PAGING_DEFPRIO</code>:
+    The default, minimum priority of the page fill worker thread.
+    The priority of the page fill work thread will be boosted boosted dynmically so that it matches the priority of the task on behalf of which it peforms the fill.
+    This defines the minimum priority that will be used.
+    Default: 50.
+  </li>
+  <li>
+    <code>CONFIG_PAGING_STACKSIZE </code>:
+    Defines the size of the allocated stack for the page fill worker thread.
+    Default: 1024.
+  </li>
+  <li>
+    <code>CONFIG_PAGING_BLOCKINGFILL</code>:
+    The architecture specific <code>up_fillpage()</code> function may be blocking or non-blocking.
+    If defined, this setting indicates that the <code>up_fillpage()</code> implementation will block until the transfer is completed.
+    Default:  Undefined (non-blocking).
+  </li>
+  <li>
+    <code>CONFIG_PAGING_TIMEOUT_TICKS</code>:
+    If defined, the implementation will monitor the (asynchronous) page fill logic.
+    If the fill takes longer than this number if microseconds, then a fatal error will be declared.
+    Default: No timeouts monitored.
+  </li>
+</ul>
 <p>
   The following can be used to disable categories of APIs supported
   by the OS.  If the compiler supports weak functions, then it