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

[Erik Österlund]

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
>