RFR (M): CR 8003985: Support @Contended Annotation - JEP 142

[Aleksey Shipilev]

Hi,

This is the daizy-fresh thread for reviewing the actual changes to
support the JEP-142 in HotSpot. Please address API issues about
@Contended to concurrency-interest list, Doug had started the thread here:

http://cs.oswego.edu/pipermail/concurrency-interest/2012-November/010208.html

We are not discussing the design, API and all the general stuff here,
only the reference implementation. I would like to have someone extra
knowledgeable in HotSpot codebase to see whether I do anything stupid there.

The webrev for the change is here:
  http://shipilev.net/pub/jdk/hotspot/contended/webrev-4/

Notable differences against latest version:
  - a little denser packing in some corner cases
  - support @Contended for static fields
  - moved @Contended to sun.misc (go and nag at c-i@ about this)
  - bugfixes

Testing:
  - hotspot/test/runtime/8003985/Test8003985 on Linux x86_64
  - jprt, specjvm98 quick run
  - jprt full cycle is underway, looking good

Thanks,
Aleksey.