Author: markt
Date: Mon May 16 14:49:04 2016
New Revision: 1744059
URL: http://svn.apache.org/viewvc?rev=1744059&view=rev
Log:
No functional change. Update comments with latest understanding of the problem.
Modified:
tomcat/tc8.5.x/trunk/ (props changed)
tomcat/tc8.5.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
Propchange: tomcat/tc8.5.x/trunk/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Mon May 16 14:49:04 2016
@@ -1 +1 @@
-/tomcat/trunk:1734785,1734799,1734845,1734928,1735041,1735044,1735480,1735577,1735597,1735599-1735600,1735615,1736145,1736162,1736209,1736280,1736297,1736299,1736489,1736646,1736703,1736836,1736849,1737104-1737105,1737112,1737117,1737119-1737120,1737155,1737157,1737192,1737280,1737339,1737632,1737664,1737715,1737748,1737785,1737834,1737860,1737959,1738005,1738007,1738014-1738015,1738018,1738022,1738039,1738043,1738059-1738060,1738147,1738149,1738174-1738175,1738261,1738589,1738623-1738625,1738643,1738816,1738850,1738855,1738946-1738948,1738953-1738954,1738979,1738982,1739079-1739081,1739087,1739113,1739153,1739172,1739176,1739191,1739474,1739726,1739762,1739775,1739814,1739817-1739818,1739975,1740131,1740324,1740465,1740495,1740508-1740509,1740520,1740535,1740707,1740803,1740810,1740969,1740980,1740991,1740997,1741015,1741033,1741036,1741058,1741060,1741080,1741147,1741159,1741164,1741173,1741181,1741190,1741197,1741202,1741208,1741213,1741221,1741225,1741232,1741409,1741501,1741677
,1741892,1741896,1741984,1742023,1742042,1742071,1742090,1742093,1742101,1742105,1742111,1742139,1742146,1742148,1742166,1742181,1742184,1742187,1742246,1742248-1742251,1742263-1742264,1742268,1742276,1742369,1742387,1742448,1742509-1742512,1742917,1742919,1742933,1742975-1742976,1742984,1742986,1743019,1743115,1743117,1743124-1743125,1743134,1743425,1743554,1743679,1743696-1743698,1743700-1743701
+/tomcat/trunk:1734785,1734799,1734845,1734928,1735041,1735044,1735480,1735577,1735597,1735599-1735600,1735615,1736145,1736162,1736209,1736280,1736297,1736299,1736489,1736646,1736703,1736836,1736849,1737104-1737105,1737112,1737117,1737119-1737120,1737155,1737157,1737192,1737280,1737339,1737632,1737664,1737715,1737748,1737785,1737834,1737860,1737959,1738005,1738007,1738014-1738015,1738018,1738022,1738039,1738043,1738059-1738060,1738147,1738149,1738174-1738175,1738261,1738589,1738623-1738625,1738643,1738816,1738850,1738855,1738946-1738948,1738953-1738954,1738979,1738982,1739079-1739081,1739087,1739113,1739153,1739172,1739176,1739191,1739474,1739726,1739762,1739775,1739814,1739817-1739818,1739975,1740131,1740324,1740465,1740495,1740508-1740509,1740520,1740535,1740707,1740803,1740810,1740969,1740980,1740991,1740997,1741015,1741033,1741036,1741058,1741060,1741080,1741147,1741159,1741164,1741173,1741181,1741190,1741197,1741202,1741208,1741213,1741221,1741225,1741232,1741409,1741501,1741677
,1741892,1741896,1741984,1742023,1742042,1742071,1742090,1742093,1742101,1742105,1742111,1742139,1742146,1742148,1742166,1742181,1742184,1742187,1742246,1742248-1742251,1742263-1742264,1742268,1742276,1742369,1742387,1742448,1742509-1742512,1742917,1742919,1742933,1742975-1742976,1742984,1742986,1743019,1743115,1743117,1743124-1743125,1743134,1743425,1743554,1743679,1743696-1743698,1743700-1743701,1744058
Modified:
tomcat/tc8.5.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
URL:
http://svn.apache.org/viewvc/tomcat/tc8.5.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java?rev=1744059&r1=1744058&r2=1744059&view=diff
==============================================================================
---
tomcat/tc8.5.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
(original)
+++
tomcat/tc8.5.x/trunk/java/org/apache/catalina/core/JreMemoryLeakPreventionListener.java
Mon May 16 14:49:04 2016
@@ -159,11 +159,11 @@ public class JreMemoryLeakPreventionList
}
/**
- * XML parsing can pin a web application class loader in memory. This is
- * particularly nasty as profilers (at least YourKit and Eclipse MAT) don't
- * identify any GC roots related to this.
- * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6916498";>
- * http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6916498</a>
+ * XML parsing can pin a web application class loader in memory. There are
+ * multiple root causes for this. Some of these are particularly nasty as
+ * profilers may not identify any GC roots related to the leak. For
example,
+ * with YourKit you need to ensure that HPROF format memory snapshots are
+ * used to be abel to trace some of the leaks.
*/
private boolean xmlParsingProtection = true;
public boolean isXmlParsingProtection() { return xmlParsingProtection; }
@@ -405,23 +405,29 @@ public class JreMemoryLeakPreventionList
* Various leaks related to the use of XML parsing.
*/
if (xmlParsingProtection) {
- /*
- * Haven't got to the root of what is going on with this
- * leak but if a web app is the first to make the following
- * two calls the web application class loader will be
pinned
- * in memory.
- */
+ // There are three known issues with XML parsing
+ // 1.
DocumentBuilderFactory.newInstance().newDocumentBuilder();
+ //
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6916498
+ // This issue is fixed in Java 7 onwards
DocumentBuilderFactory factory =
DocumentBuilderFactory.newInstance();
try {
DocumentBuilder documentBuilder =
factory.newDocumentBuilder();
- // Bug 58486 identified two additional memory leaks.
- // The first is in DOMSerializerImpl.abort
+
+ // The 2nd and 3rd links both relate to cached
Exception
+ // instances that retain a link to the TCCL via the
+ // backtrace field. Note that YourKit only shows this
+ // field when using the HPROF format memory snapshots.
+ // https://bz.apache.org/bugzilla/show_bug.cgi?id=58486
+ // These issues are currently present in all current
+ // versions of Java
+
+ // 2.
com.sun.org.apache.xml.internal.serialize.DOMSerializerImpl
Document document = documentBuilder.newDocument();
document.createElement("dummy");
DOMImplementationLS implementation =
(DOMImplementationLS)document.getImplementation();
implementation.createLSSerializer().writeToString(document);
- // The second leak is in DOMNormalizer
+ // 3.
com.sun.org.apache.xerces.internal.dom.DOMNormalizer
document.normalize();
} catch (ParserConfigurationException e) {
log.error(sm.getString("jreLeakListener.xmlParseFail"),
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