RFR 8066171: Out of order with Metaspace allocation lock

David Holmes david.holmes at oracle.com
Fri Dec 5 03:53:03 UTC 2014

Hi Coleen,

Do you care that you can now block at safepoints when acquiring the lock?


On 4/12/2014 2:59 AM, Coleen Phillimore wrote:
> Summary: Lock resolved_references instead.
> When I took out the constant pool mutex, I thought I could use the
> metaspace to synchronize this code sequence, but the metaspace_lock is
> out of order with the DirtyCardQ_CBL_mon lock that can sometimes be
> taken with obj_at_put() in an object array.   Since there is always a
> resolved_reference objArrayOop attached to this class, we can lock this
> for this cpCache entry.  John and the JSR292 guys tell me that this code
> sequence needs to be locked against multiple setters.
> Tested with jdk/test/java/lang/invoke tests, nsk.quick.testlist.
> open webrev at http://cr.openjdk.java.net/~coleenp/8066171/
> bug link https://bugs.openjdk.java.net/browse/JDK-8066171
> Thanks,
> Coleen

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