Code review request: three native memory tracking related bugs

[Zhengyu Gu]

Hi Vladmire,

Thanks for reviewing.

>> 7182543: NMT ON: Aggregate a few NMT related bugs
>> CRhttp://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7182543
>> Webrev: http://cr.openjdk.java.net/~zgu/7182543/webrev.00/
>
> I think the next should be guarantee() instead of check since all 
> MemRecorders should be deleted in preceding code:
>
>  if (MemRecorder::_instance_count == 0) {
>
Not necessary true, it depends on when "shutdown_pending" flag is 
visible to a particular thread, that thread can still generate pending 
recorders when they are overflown.

Thanks,

-Zhengyu


> Vladimir
>
>>
>> - Fixed generations_in_used calculation
>> - Wait MemRecorder instance count to drop to zero before completely 
>> shutdown NMT
>> - Added assertion for JavaThread in _thread_blocked state.
>>
>>
>> Thanks,
>>
>> -Zhengyu
>>