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

[David Holmes]

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() ??

> 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.

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
>