RE: [wtp-dev] OutOfMemory in PermGen

["Raev, Kaloyan" <kaloyan.raev@xxxxxxx>]

Hmm,

 

This is very strange. As far as I am aware of the Sun VM, the object heap memory (the one defined by Xmx) and the class definition memory (the one defined by XXMaxPermSize) do not share one and the same area of physical memory. I mean if say you have -Xmx512m and XXMaxPermSize=256m, then you actually say that the VM will consume a maximum of 512+256 MB of physical memory, not maximum of 512 MB, where 256 MB of them is for objects and 256 MB for class definitions.

 

And there are 2 kinds of OutOfMemoryErrors:

  1) when new object cannot be created - there is not enough memory in the object heap. This happens during a construction of new object. In most cases, in Sun VM (at least up to version 1.4) you don't have even a stack trace.

  2) when a class is attempted to be loaded - there is not enough memory in the PermGen. This happens when a Classloader tries to load new class. You have a stack trace in this case (like the one in my mail below) and you have exception message "OutOfMemoryError: PermGen".

 

So, in theory, it looks quite strange to me that if you decrease the PermSize of the VM, then you stop getting OutOfMemory in the PermSize. And, what people try to do in such situation is to _increase_ the PermSize, not _decrease_ it...

 

This really needs to be investigated.

 

Greetings,

Kaloyan

---

From: wtp-dev-bounces@xxxxxxxxxxx [mailto:wtp-dev-bounces@xxxxxxxxxxx] On Behalf Of Peter Moogk
Sent: Friday, August 31, 2007 5:28 PM
To: General discussion of project-wide or architectural issues.
Subject: Re: [wtp-dev] OutOfMemory in PermGen

Hi Raev, 
     I ran into the same problem while 
doing my smoke testing as well.  I talked to John Lanuti about this. 
 He indicated that he usually uses a setting of -Xmx512M 
-XXMaxPermSize=128m, so I used this setting as well, which stopped the OOM 
errors from occuring.   This setting actually reduces the Perm size in 
half, but doubles the other memory setting.   This seemed to work for me. 
 I'm a bit concerned as well that somewhere along the line a memory leak 
may have been introduced.  Are there any performance guys out there that 
could verify whether or not there is a memory leak.  Thanks. 


Peter Moogk
Rational Web Services 
Development
IBM Canada 
Ltd.
pmoogk@xxxxxxxxxx
D3-353/ENX/8200/MKM
(905) 413-3458

"Raev, Kaloyan" <kaloyan.raev@xxxxxxx>
Sent by: wtp-dev-bounces@xxxxxxxxxxx

08/31/2007 02:52 AM

Please respond to
"General discussion of project-wide or architectural issues."        <wtp-dev@xxxxxxxxxxx>

To	<wtp-dev@xxxxxxxxxxx>
cc
Subject	[wtp-dev] OutOfMemory in PermGen

Hello,

Yesterday, while I was executing the smoke tests on the wtp-sdk-M-2.0.1-20070830145135 build I got OutOfMemoryError: PermGen… 3 times. This means:

1. I execute smoke test steps.
2. OOM is thrown - restart Eclipse.
3. Continue smoke test steps.
4. OOM is thrown - restart Eclipse.
5. Continue smoke test steps.
6. OOM is thrown - restart Eclipse.
7. Finish smoke test scenario.

This is the first time I have ever got OutOfMemory in the PermGen on a pure WTP stack. Reading the eclipse.ini file I see that the MaxPermSize is set to 256M, which is a significant value. While this can be easily worked around by increasing the MaxPermSize value, I am quite anxious what has happened lately that so many classes are loaded. It is just opening few wizards and views that are enough to spent all of the PermGen.

Has anybody else got the same problem?

Which is the bugzilla component where I should report bugs like this one?

Here is an example of the OOM error from my .log file.

!ENTRY org.eclipse.ui 4 0 2007-08-30 21:53:19.434
!MESSAGE Unhandled event loop exception
!STACK 0
java.lang.OutOfMemoryError: PermGen space
       at java.lang.ClassLoader.defineClass1(Native Method)
       at java.lang.ClassLoader.defineClass(Unknown Source)
       at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.defineClass(DefaultClassLoader.java:161)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.defineClass(ClasspathManager.java:501)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findClassImpl(ClasspathManager.java:471)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClassImpl(ClasspathManager.java:430)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:413)
       at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:189)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findLocalClass(BundleLoader.java:340)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:408)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:369)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:357)
       at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:83)
       at java.lang.ClassLoader.loadClass(Unknown Source)
       at java.lang.ClassLoader.loadClassInternal(Unknown Source)
       at java.lang.ClassLoader.defineClass1(Native Method)
       at java.lang.ClassLoader.defineClass(Unknown Source)
       at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.defineClass(DefaultClassLoader.java:161)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.defineClass(ClasspathManager.java:501)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findClassImpl(ClasspathManager.java:471)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClassImpl(ClasspathManager.java:430)
       at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:413)
       at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:189)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findLocalClass(BundleLoader.java:340)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:408)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:369)
       at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:357)
       at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:83)
       at java.lang.ClassLoader.loadClass(Unknown Source)
       at java.lang.ClassLoader.loadClassInternal(Unknown Source)
       at org.eclipse.wst.server.ui.internal.view.servers.ServerActionHelper.fillNewContextMenu(ServerActionHelper.java:49)

        at org.eclipse.wst.server.ui.internal.view.servers.ServersView.fillContextMenu(ServersView.java:319)

Greetings,
Kaloyan Raev
Senior Developer
NW C JS TOOLS JEE (BG)
SAP Labs Bulgaria
T +359/2/9157-416
mailto:kaloyan.raev@xxxxxxx
www.sap.com _______________________________________________
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