Request for review 6988439: Parallel Class Loading test deadlock involving MethodData_lock and Pend, ing List Lock

[Coleen Phillimore]

Tom Rodriguez wrote:
> On Dec 9, 2010, at 8:35 AM, Coleen Phillimore wrote:
>
>   
>> Summary: Don't acquire methodData_lock while holding pending list lock
>>
>> We discussed the alternative of allocating the methodData object from permgen before acquiring the MethodData_lock, but were concerned about leaking methodData objects in the permgen if another thread beats us to the locked region.  When we go to native memory for these objects this bug fix will be moot and removed.  This patch is to prevent the various hangs we've seen from occurring until then.
>>     
>
> Do any of the caller assume that it if didn't trap that an MDO was created?
>   
No, they both check for null return and do nothing for that.  The 
callers have always expected that it could return null.  The next time 
the function is called, and if null it'll try to create an MDO again.

Coleen
> tom
>
>   
>> open webrev at http://cr.openjdk.java.net/~coleenp/6922246/
>> bug link at http://bugs.sun.com/view_bug.do?bug_id=6922246
>>
>> Thanks,
>> Coleen
>>     
>
>