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<div class="moz-cite-prefix">On 05/06/2013 05:03 PM, Alan Bateman
wrote:<br>
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<blockquote cite="mid:5187C649.60903@oracle.com" type="cite"><!--[if !IE]><DIV style="border-left: 2px solid #009900; border-right: 2px solid #009900; padding: 0px 15px; margin: 2px 0px;"><![endif]-->On
06/05/2013 09:02, Thomas Schatzl wrote:
<br>
<blockquote type="cite"><!--[if !IE]><DIV style="border-left: 2px solid #009900; border-right: 2px solid #009900; padding: 0px 15px; margin: 2px 0px;"><![endif]-->:
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Alan also mentioned something about instrumentation that can add
memory
<br>
allocations basically anywhere.
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As the reference handler code is plain java code, it will be
affected as
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other java code.
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<!--[if !IE]></DIV><![endif]--></blockquote>
I mentioned instrumentation on the off-chance that there was more
to this puzzle.
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<br>
I think Peter is right and the allocation of the
InterruptedException seems to be the only place where OOME is
possible in this code. Do you know if these tests call
Thread.interrupt on random threads (maybe as a stress test)? It is
possible to get a reference to the Reference Handler thread via
Thread.getAllStackTraces and a few other APIs so maybe this what
is going on. If the tests aren't calling interrupt on random
threads then it suggests to me that there is something else going
on, maybe there is a lurking VM bug.
<br>
<br>
In any case, it seems safe to catch/ignore OOME here. One of the
mails mentioned ThreadDeath and I don't know if want to expand the
scope of the patch. That seems a case where it should be like the
Cleaner and terminate the VM.
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<br>
I mentioned ThreadDeath as another possibility, similar to
InterruptedException, that could cause OOME. OOME that would result
from unsuccessful allocation of ThreadDeath error object in victim
thread should not be ignored though. But it seems that JVM designers
have already taken care of that, because contrary to
InterruptedException the ThreadDeath error object is allocated in
thread executing Thread.stop() method and this instance is later
raised as exception in victim thread. So OOME in Object.wait() can
only be caused by unsuccessful allocation of InterruptedException
and nothing else. That was my final conclusion. ThreadDeath thrown
in ReferenceHandler thread should not be caught and ignored.<br>
<br>
Regards, Peter<br>
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<blockquote cite="mid:5187C649.60903@oracle.com" type="cite"><!--[if !IE]><DIV style="border-left: 2px solid #009900; border-right: 2px solid #009900; padding: 0px 15px; margin: 2px 0px;"><![endif]-->
<br>
-Alan.
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