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JETTY-937 More JVM bug work arounds. Insert pause if all else fails 

git-svn-id: svn+ssh://dev.eclipse.org/svnroot/rt/org.eclipse.jetty/jetty/trunk@976 7e9141cc-0065-0410-87d8-b60c137991c4
This commit is contained in:
Greg Wilkins 2009-10-06 14:36:57 +00:00
parent 347982809d
commit d94bdb791f
2 changed files with 111 additions and 35 deletions
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1
VERSION.txt
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@ -7,6 +7,7 @@ jetty-7.0.1-SNAPSHOT
+ 289027 deobfuscate HttpClient SSL passwords
+ 289959 Improved ContextDeployer configuration
+ 289960 start.jar assumes command line args are configs
+ JETTY-937 More JVM bug work arounds. Insert pause if all else fails
+ JETTY-1114 unsynchronised WebAppClassloader.getResource(String)
+ Fixed XSS issue in CookieDump demo servlet.
+ 291340 Race condition in onException() notifications

145
jetty-io/src/main/java/org/eclipse/jetty/io/nio/SelectorManager.java
View File

@ -42,19 +42,18 @@ import org.eclipse.jetty.util.thread.Timeout;
*/
public abstract class SelectorManager extends AbstractLifeCycle
{
private static final int __JVMBUG_THRESHHOLD=Integer.getInteger("org.eclipse.jetty.io.nio.JVMBUG_THRESHHOLD",128);
private static final int __JVMBUG_THRESHHOLD2=__JVMBUG_THRESHHOLD*2;
private static final int __JVMBUG_THRESHHOLD1=(__JVMBUG_THRESHHOLD2+__JVMBUG_THRESHHOLD)/2;
private static final int __JVMBUG_THRESHHOLD=Integer.getInteger("org.mortbay.io.nio.JVMBUG_THRESHHOLD",512).intValue();
private static final int __MONITOR_PERIOD=Integer.getInteger("org.mortbay.io.nio.MONITOR_PERIOD",1000).intValue();
private static final int __MAX_SELECTS=Integer.getInteger("org.mortbay.io.nio.MAX_SELECTS",15000).intValue();
private static final int __BUSY_PAUSE=Integer.getInteger("org.mortbay.io.nio.BUSY_PAUSE",50).intValue();
private long _maxIdleTime;
private long _lowResourcesConnections;
private long _lowResourcesMaxIdleTime;
private transient SelectSet[] _selectSet;
private int _selectSets=1;
private volatile int _set;
private boolean _jvmBug0;
private boolean _jvmBug1;
/* ------------------------------------------------------------ */
/**
* @param maxIdleTime The maximum period in milli seconds that a connection may be idle before it is closed.
@ -295,9 +294,18 @@ public abstract class SelectorManager extends AbstractLifeCycle
private int _change;
private int _nextSet;
private Selector _selector;
private int _jvmBug;
private volatile Thread _selecting;
private long _lastJVMBug;
private int _jvmBug;
private int _selects;
private long _monitorStart;
private long _monitorNext;
private boolean _pausing;
private SelectionKey _busyKey;
private long _log;
private int _paused;
private int _jvmFix0;
private int _jvmFix1;
private int _jvmFix2;
/* ------------------------------------------------------------ */
SelectSet(int acceptorID) throws Exception
@ -313,6 +321,9 @@ public abstract class SelectorManager extends AbstractLifeCycle
// create a selector;
_selector = Selector.open();
_change=0;
_monitorStart=System.currentTimeMillis();
_monitorNext=_monitorStart+__MONITOR_PERIOD;
_log=_monitorStart+60000;
}
/* ------------------------------------------------------------ */
@ -360,7 +371,6 @@ public abstract class SelectorManager extends AbstractLifeCycle
_change=_change==0?1:0;
selector=_selector;
}
// Make any key changes required
final int size=changes.size();
@ -463,29 +473,85 @@ public abstract class SelectorManager extends AbstractLifeCycle
// Do the select.
if (wait > 0)
{
// If we are in pausing mode
if (_pausing)
{
try
{
Thread.sleep(__BUSY_PAUSE); // pause to reduce impact of busy loop
}
catch(InterruptedException e)
{
Log.ignore(e);
}
}
long before=now;
int selected=selector.select(wait);
now = System.currentTimeMillis();
_idleTimeout.setNow(now);
_timeout.setNow(now);
// Look for JVM bugs
_selects++;
// Look for JVM bugs over a monitor period.
// http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6403933
if (__JVMBUG_THRESHHOLD>0 && selected==0 && wait>__JVMBUG_THRESHHOLD && (now-before)<(wait/2) )
// http://bugs.sun.com/view_bug.do?bug_id=6693490
if (now>_monitorNext)
{
_selects=(int)(_selects*__MONITOR_PERIOD/(now-_monitorStart));
_pausing=_selects>__MAX_SELECTS;
if (_pausing)
_paused++;
_selects=0;
_jvmBug=0;
_monitorStart=now;
_monitorNext=now+__MONITOR_PERIOD;
}
if (now>_log)
{
if (_paused>0)
Log.info(this+" Busy selector - injecting delay "+_paused+" times");
if (_jvmFix2>0)
Log.info(this+" JVM BUG(s) - injecting delay"+_jvmFix2+" times");
if (_jvmFix1>0)
Log.info(this+" JVM BUG(s) - recreating selector "+_jvmFix1+" times, canceled keys "+_jvmFix0+" times");
else if(Log.isDebugEnabled() && _jvmFix0>0)
Log.info(this+" JVM BUG(s) - canceled keys "+_jvmFix0+" times");
_paused=0;
_jvmFix2=0;
_jvmFix1=0;
_jvmFix0=0;
_log=now+60000;
}
// If we see signature of possible JVM bug, increment count.
if (selected==0 && wait>10 && (now-before)<(wait/2))
{
// Increment bug count and try a work around
_jvmBug++;
if (_jvmBug>=(__JVMBUG_THRESHHOLD2))
if (_jvmBug>(__JVMBUG_THRESHHOLD))
{
try
{
if (_jvmBug==__JVMBUG_THRESHHOLD+1)
_jvmFix2++;
Thread.sleep(__BUSY_PAUSE); // pause to avoid busy loop
}
catch(InterruptedException e)
{
Log.ignore(e);
}
}
else if (_jvmBug==__JVMBUG_THRESHHOLD)
{
synchronized (this)
{
_lastJVMBug=now;
if (_jvmBug1)
Log.debug("seeing JVM BUG(s) - recreating selector");
else
{
_jvmBug1=true;
Log.info("seeing JVM BUG(s) - recreating selector");
}
// BLOODY SUN BUG !!! Try refreshing the entire selector.
final Selector new_selector = Selector.open();
for (SelectionKey k: selector.keys())
@ -503,37 +569,46 @@ public abstract class SelectorManager extends AbstractLifeCycle
}
_selector.close();
_selector=new_selector;
_jvmBug=0;
return;
}
}
else if (_jvmBug==__JVMBUG_THRESHHOLD || _jvmBug==__JVMBUG_THRESHHOLD1)
else if (_jvmBug%32==31) // heuristic attempt to cancel key 31,63,95,... loops
{
// Cancel keys with 0 interested ops
if (_jvmBug0)
Log.debug("seeing JVM BUG(s) - cancelling interestOps==0");
else
{
_jvmBug0=true;
Log.info("seeing JVM BUG(s) - cancelling interestOps==0");
}
int cancelled=0;
for (SelectionKey k: selector.keys())
{
if (k.isValid()&&k.interestOps()==0)
{
k.cancel();
cancelled++;
}
}
if (cancelled>0)
_jvmFix0++;
return;
}
}
else
_jvmBug=0;
else if (selected==1 && _selects>__MAX_SELECTS)
{
// Look for busy key
SelectionKey busy = (SelectionKey)selector.selectedKeys().iterator().next();
if (busy==_busyKey)
{
SelectChannelEndPoint endpoint = (SelectChannelEndPoint)busy.attachment();
Log.warn("Busy Key "+busy+" "+endpoint);
busy.cancel();
if (endpoint!=null)
endpoint.close();
}
_busyKey=busy;
}
}
else
{
selector.selectNow();
_jvmBug=0;
_selects++;
}
// have we been destroyed while sleeping
@ -704,7 +779,7 @@ public abstract class SelectorManager extends AbstractLifeCycle
{
return _selector;
}
/* ------------------------------------------------------------ */
void stop() throws Exception
{
@ -763,7 +838,7 @@ public abstract class SelectorManager extends AbstractLifeCycle
synchronized (System.err)
{
Selector selector=_selector;
Log.info("SelectSet "+_setID+" "+selector.keys().size()+" lastJVMBug="+new Date(_lastJVMBug));
Log.info("SelectSet "+_setID+" "+selector.keys().size());
for (SelectionKey key: selector.keys())
{
if (key.isValid())