RFR (S) 8213723 / 8213893 - More Monitor/mutex initialization management
David Holmes
david.holmes at oracle.com
Thu Nov 15 22:37:30 UTC 2018
Thanks Coleen!
David
On 16/11/2018 1:44 am, coleen.phillimore at oracle.com wrote:
> This looks good.
> Coleen
>
> On 11/14/18 11:24 PM, David Holmes wrote:
>> webrev: http://cr.openjdk.java.net/~dholmes/8213723/webrev/
>>
>> bug: https://bugs.openjdk.java.net/browse/JDK-8213723
>>
>> I found a bunch of mutex/monitor instances that are dynamically
>> created and embedded in classes rather than being part of the global
>> mutex table. This isn't necessarily a problem as long as they aren't
>> created before the low-level mutex initialization code has executed. I
>> added some debug code to verify no mutex/monitor is created before
>> os::init_2() has executed (which is a constraint imposed by Solaris
>> sync code being dependent on argument parsing).
>>
>> I found one mutex that was created too soon, and that was the
>> NMTQuery_lock, so that is now moved to the global list in MutexLocker.
>> It's only used with the NMT DCmd and so doesn't need to be created
>> exceptionally early.
>>
>> Just a reminder we don't see any problems today because mutex/monitor
>> construction is trivial and independent of everything else. But the
>> mutex/monitor rewrite that is being worked on requires OS
>> initialization of mutex related attributes.
>>
>> Also trivially fixed:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8213893
>>
>> which deletes the unused StringTable_lock.
>>
>> Thanks,
>> David
>
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