added a small section on returning memory to the kernel by compacting the
* doc/xml.html doc/xmlmem.html: added a small section on returning
memory to the kernel by compacting the heap provided by Wolfram Sang
Daniel
svn path=/trunk/; revision=3682
diff --git a/ChangeLog b/ChangeLog
index b16f241..716dbfc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Feb 4 17:48:30 CET 2008 Daniel Veillard <daniel@veillard.com>
+
+ * doc/xml.html doc/xmlmem.html: added a small section on returning
+ memory to the kernel by compacting the heap provided by Wolfram Sang
+
Fri Jan 25 20:01:42 CET 2007 Rob Richards <rrichards@ctindustries.net>
* include/win32config.h win32/Makefile.msvc: fix build under VS 2008.
diff --git a/doc/xml.html b/doc/xml.html
index 355dbed..bd46fad 100644
--- a/doc/xml.html
+++ b/doc/xml.html
@@ -3359,6 +3359,7 @@
<li><a href="#cleanup">Cleaning up after parsing</a></li>
<li><a href="#Debugging">Debugging routines</a></li>
<li><a href="#General4">General memory requirements</a></li>
+ <li><a href="#Compacting">Returning memory to the kernel</a></li>
</ol>
<h3><a name="General3">General overview</a></h3>
@@ -3497,6 +3498,20 @@
</ul>
<p></p>
+<h3><a name="Compacting">Returning memory to the kernel</a></h3>
+
+<p>You may encounter that your process using libxml2 does not have a
+reduced memory usage although you freed the trees. This is because
+libxml2 allocates memory in a number of small chunks. When freeing one
+of those chunks, the OS may decide that giving this little memory back
+to the kernel will cause too much overhead and delay the operation. As
+all chunks are this small, they get actually freed but not returned to
+the kernel. On systems using glibc, there is a function call
+"malloc_trim" from malloc.h which does this missing operation (note that
+it is allowed to fail). Thus, after freeing your tree you may simply try
+"malloc_trim(0);" to really get the memory back. If your OS does not
+provide malloc_trim, try searching for a similar function.</p>
+<p></p>
<h2><a name="Encodings">Encodings support</a></h2>
diff --git a/doc/xmlmem.html b/doc/xmlmem.html
index 1ca4334..5437e73 100644
--- a/doc/xmlmem.html
+++ b/doc/xmlmem.html
@@ -12,6 +12,7 @@
<li><a href="#cleanup">Cleaning up after parsing</a></li>
<li><a href="#Debugging">Debugging routines</a></li>
<li><a href="#General4">General memory requirements</a></li>
+ <li><a href="#Compacting">Returning memory to the kernel</a></li>
</ol><h3><a name="General3" id="General3">General overview</a></h3><p>The module <code><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
provides the interfaces to the libxml2 memory system:</p><ul><li>libxml2 does not use the libc memory allocator directly but xmlFree(),
xmlMalloc() and xmlRealloc()</li>
@@ -99,4 +100,14 @@
validation, DOM, XPath or XPointer, don't use entities, need to work with
fixed memory requirements, and try to get the fastest parsing possible
then the SAX interface should be used, but it has known restrictions.</li>
-</ul><p></p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>
+</ul><p></p><h3><a name="Compacting" id="Compacting">Returning memory to the kernel</a></h3><p>You may encounter that your process using libxml2 does not have a
+reduced memory usage although you freed the trees. This is because
+libxml2 allocates memory in a number of small chunks. When freeing one
+of those chunks, the OS may decide that giving this little memory back
+to the kernel will cause too much overhead and delay the operation. As
+all chunks are this small, they get actually freed but not returned to
+the kernel. On systems using glibc, there is a function call
+"malloc_trim" from malloc.h which does this missing operation (note that
+it is allowed to fail). Thus, after freeing your tree you may simply try
+"malloc_trim(0);" to really get the memory back. If your OS does not
+provide malloc_trim, try searching for a similar function.</p><p></p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>