RFR: 8010151 nsk/regression/b6653214 fails "assert(snapshot != NULL) failed: Worker should not be started"

[Zhengyu Gu]

Hi David,

On Apr 8, 2013, at 8:44 PM, David Holmes wrote:

> Hi Zhengyu,
> 
> On 9/04/2013 6:44 AM, Zhengyu Gu wrote:
>> Second round.
>> 
>> It fixed a racing condition when NMT is being shutdown while worker thread just started. The race causes get_snapshot() to return NULL, that triggers the assertion.
> 
> I can't see where get_snapshot() is now called such that we know we have a snapshot when calling start_worker() ??
> 
Now, snapshot is passed to MemTrackWorker from MemTracker::start(), the method ensures that snapshot is properly created and initialized before calling start_worker().

>> It also fixed a few volatile pointers that were mistakenly declared as volatile objects.
> 
> There is some further cleanup here:
> 
> 209 // delete all pooled recorders
> 210 void MemTracker::delete_all_pooled_recorders() {
> 211   // free all pooled recorders
> 212   volatile MemRecorder* cur_head = _pooled_recorders;
> 
> cur_head declaration is no longer correct.
> 

Thanks for finding this, I will fix it.

Thanks,

-Zhengyu

> David
> -----
> 
>> 
>> Bug:       http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8010151
>> Webrev: http://cr.openjdk.java.net/~zgu/8010151/webrev.01/
>> 
>> Tests:
>>   - JPRT
>>   - vm.quick.testlist on Linux x86 and Windows x64
>>   - The approach described by Christian in bug report. I were able to reproduce on prior the fix, and it is no longer reproducible after.
>> 
>> 
>> 
>> Thanks,
>> 
>> -Zhengyu
>>