RFR: 8013651 NMT: reserve/release sequence id's in incorrect order due to race

[Zhengyu Gu]

There can be race conditions between the memory operations and the book 
keeping records are written. For example, thread 1 releases a virtual 
memory block, before it can write the release record, thread 2 reserves 
the same virtual memory block and writes reservation first, as result, 
NMT indicates the block is "released".

The solution is that, for those operations that can cause the race 
conditions, NMT should pre-reserve sequence number for it, if the 
operation succeeds, NMT uses pre-reserved sequence number to write the 
record.

The tricky part is that, a sequence number is only good for the 
generation it is acquired, when there are reserved sequence number, NMT 
has to prevent itself from entering so called "sync-point" where the 
generation can be advanced.


Bug: http://bugs.sun.com/view_bug.do?bug_id=8013651
Webrev: http://cr.openjdk.java.net/~zgu/8013651/webrev/ 
<http://cr.openjdk.java.net/%7Ezgu/8013651/webrev/>


Tests:
    1) JPRT
    2) vm.quick.testlist on Linux 32, Linux x64 and Solaris Sparcv9
    3) Kitchensink on Linux 32, Linux x64, Solaris Sparcv9 and Windows x64
    4) NMT jtreg tests on Linux 32, Linux x64 and Solaris Sparcv9


Thanks,

-Zhengyu