RFR(s): 8198369: Clean up GCId and GCIdMark

[Per Liden]

Thanks Erik!

/Per

On 02/19/2018 02:57 PM, Erik Österlund wrote:
> Hi Per,
> 
> Looks good.
> 
> Thanks,
> /Erik
> 
> On 2018-02-19 14:38, Per Liden wrote:
>> After discussing "8198267: Allow GCId::current_raw() calls from 
>> non-NamedThreads", we noticed the need to do some additional cleanups 
>> of GCId and GCIdMark. So here's a patch for that.
>>
>> In short, GCIdMarkAndRestore is not really needed, we can let the 
>> normal GCIdMark have the restore semantics and get rid of 
>> GCIdMarkAndRestore. GCId and GCIdMark can also be cleaned up a bit, 
>> for example. the GCIdMark::_gc_id member is unnecessary, some 
>> functions return "const uint" instead of "uint", etc.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8198369
>> Webrev: http://cr.openjdk.java.net/~pliden/8198369/webrev.0/
>>
>> /Per
>>
>