RFR (S): 8228857: Refactor PlatformMonitor into PlatformMutex and PlatformMonitor

[dean.long at oracle.com]

Looks good to me.

dl

On 8/5/19 6:49 PM, David Holmes wrote:
> Ping!
>
> On 2/08/2019 9:03 am, David Holmes wrote:
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8228857
>> webrev: http://cr.openjdk.java.net/~dholmes/8228857/webrev/
>>
>> As suggested by Per Liden when PlatformMonitor was introduced by 
>> JDK-8210832 we should refactor PlatformMonitor into a simpler 
>> PlatformMutex extended by PlatformMonitor. That would potentially 
>> allow other synchronization objects e.g. Zlocks, to be replaced by a 
>> suitable PlatformX class, and allows us to redefine JVM_RawMonitor 
>> support to use it (forthcoming change).
>>
>> The refactoring would be obvious and simple if not for the macOS 
>> PThread allocation bug workaround. I had to change the Posix variant 
>> so that we only use the Impl helper class on macOS, so that we can 
>> separate the allocation of the pthread_mutex_t and pthread_cond_t. 
>> For macOS both get allocated in the PlatformMutex.
>>
>> There are not actual usage changes in this RFE.
>>
>> Testing: mach5 tiers 1-3
>>
>> Thanks,
>> David
>> -----