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Hello Erik,<br>
<br>
Yes, this fix solves the same problem for CMS collector.<br>
<br>
regards,<br>
Poonam<br>
<br>
<div class="moz-cite-prefix">On 6/11/2015 6:19 AM, Erik Österlund
wrote:<br>
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<blockquote cite="mid:106B0CC6-F1FA-4AD8-969D-9D9640C039CD@lnu.se"
type="cite">
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Hi Poonam,
<div class=""><br class="">
</div>
<div class="">Just out of curiosity, does this fix exactly the
same problem for G1? I found the other day that it currently
does not respect -Xnoclassgc and had to make workarounds for
that so the C2 compiler wouldn’t hang, as can be seen in this
webrev:</div>
<div class=""><a moz-do-not-send="true"
href="http://cr.openjdk.java.net/%7Eeosterlund/g1_dynamic_elision/noclassgc/webrev.00/"
class="">http://cr.openjdk.java.net/~eosterlund/g1_dynamic_elision/noclassgc/webrev.00/</a></div>
<div class=""><br class="">
</div>
<div class="">Thanks,</div>
<div class="">/Erik</div>
<div class=""><br class="">
<div>
<blockquote type="cite" class="">
<div class="">On 10 Jun 2015, at 23:20, Poonam Bajaj Parhar
<<a moz-do-not-send="true"
href="mailto:poonam.bajaj@oracle.com" class="">poonam.bajaj@oracle.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
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charset=UTF-8" class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> Please
review the code changes to fix:<br class="">
<a moz-do-not-send="true" id="key-val" rel="4786055"
href="https://bugs.openjdk.java.net/browse/JDK-8085965"
class="">JDK-8085965:</a> VM hangs in C2Compiler <br
class="">
<br class="">
Problem and fix: <br class="">
In JDK8, CMSClassUnloadingEnabled option which is used
to control the class-unloading in CMS, was enabled by
default. But if the user specifies -Xnoclassgc or
-XX:-ClassUnloading on the command line then classes get
unloaded but updating of subklasses/siblings links gets
skipped by the ClassUnloading check in the following
function:<br class="">
<br class="">
<span id="mainframespan" class=""><tt class=""><i
class="">void
Klass::clean_weak_klass_links(BoolObjectClosure*
is_alive, bool </i> <br class="">
<i class="">clean_alive_klasses) {</i> <br
class="">
<i class=""> if (!ClassUnloading) {</i> <br
class="">
<i class=""> return;</i> <br class="">
<i class=""> }<br class="">
<br class="">
</i></tt></span>which corrupts the class hierarchy
links causing hangs and crashes. <br class="">
<br class="">
This fix honors -XX:-ClassUnloading and -Xnoclassgc
options and disables class unloading with CMS.<br
class="">
<br class="">
Webrev: <a moz-do-not-send="true"
class="moz-txt-link-freetext"
href="http://cr.openjdk.java.net/%7Epoonam/8085965/webrev/">http://cr.openjdk.java.net/~poonam/8085965/webrev/</a><br
class="">
<br class="">
Thanks,<br class="">
Poonam<br class="">
<br class="">
</div>
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