RFR 8035735: Metaspace::contains become extremely slow in some cases

Coleen Phillimore coleen.phillimore at oracle.com
Fri Feb 28 13:57:35 PST 2014

On 2/28/2014 4:48 PM, Jon Masamitsu wrote:
> Coleen,
> You're casting something to a Method*, right?  Is
> that assert ever going to fail?

It's not going to fail the assert, but it might crash trying to access 
the Metadata vtable if it's not metadata.   I debated this with myself - 
would we rather have a SEGV there or no assert at all and some problem 
later on?  We don't have a faster way to check whether somethings in the 
metaspace that is safe from CMS deleting mmap regions while we look at them.

> Jon
> On 2/28/2014 12:08 PM, Coleen Phillimore wrote:
>> Summary: Call is_metadata instead which does less work for the call 
>> in debugInfo.hpp which is called for all compiled code stack frames.
>> open webrev at http://cr.openjdk.java.net/~coleenp/8035735/
>> bug link https://bugs.openjdk.java.net/browse/JDK-8035735
>> Tested with failing test case, nsk.quick.testlist, jcks and jtreg tests.
>> Coleen

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