Round 3: RFR: 8013651 NMT: reserve/release sequence id's in incorrect order due to race

[Coleen Phillimore]

This looks good, Zhengyu.
Coleen

On 06/04/2013 10:26 AM, Zhengyu Gu wrote:
> Round 3:
>
> Based on Coleen and Stefan's comment, reverted most of NMT tracking 
> calls to original to reduce code changes.
>
> http://cr.openjdk.java.net/~zgu/8013651/webrev.03/ 
> <http://cr.openjdk.java.net/%7Ezgu/8013651/webrev.03/>
>
>
> Tests:
>   JPRT
>   vm.quick.testlist on Linux 32
>
> Thanks,
>
> -Zhengyu
>
>
> On 5/22/2013 10:28 AM, Zhengyu Gu wrote:
>> Based on the discussion with Karen, Coleen and Harold, following 
>> changes are made:
>>
>> 1) Renamed NMTTrackOp to NMTTracker, avoid the confusion with VM 
>> operations.
>> 2) Used NMTTracker's dtor to discard the tracking operation if no 
>> recording is done.
>>
>> Tests:
>>  - JPRT
>>  - vm.quick.testlist on Linux 32, Solaris sparcv9 and Windows 32.
>>
>> Thanks,
>>
>> -Zhengyu
>>
>>
>> On 5/14/2013 10:01 AM, Zhengyu Gu wrote:
>>> 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
>>
>