RFR 8213150: Add verification for locking by VMThread

[coleen.phillimore at oracle.com]

On 9/24/19 2:28 AM, Robbin Ehn wrote:
> Hi Coleen,
>
> First, a side note, I notice that we forgot to change, e.g.:
> Monitor::_safepoint_check_never to Mutex::_safepoint_check_never in 
> some places.

I'll fix these two:

http://cr.openjdk.java.net/~coleenp/2019/8213150.02/webrev/src/hotspot/share/utilities/events.hpp.udiff.html

http://cr.openjdk.java.net/~coleenp/2019/8213150.02/webrev/src/hotspot/share/utilities/concurrentHashTable.inline.hpp.udiff.html

And file an RFE for the ones in mutexLocker.cpp.

I'd left Monitor::_safepoint_check_never in places where the code had 
new Monitor(etc, Monitor::_safepoint_check_never); ie. the code was 
initializing a Monitor, but there are a lot of mechanical changes that 
we could do to change them all.

thanks!
Coleen

>
>>
>> I'm going to work on the issues with 'special' locks as part of : 
>> https://bugs.openjdk.java.net/browse/JDK-8184732 next, but the 
>> rewriting (below) removed these two uses of this ranking check.
>
> Ok
>
>>
>>>
>>> do_safepoint_check is checked four times (once via not_allowed), can 
>>> you please re-write this method, or better yet remove the bool input.
>>> The bool is hardcoded so can you just create two methods, with one 
>>> helper method for the common checks. (yes there will be more code, 
>>> but readable :) )
>>
>> This is a good suggestion.  I've rewritten it to be a lot clearer, 
>> and am retesting it now with tier1 (all Oracle platforms) and tier2,3 
>> linux-x64-debug.
>>
>> incremental webrev at 
>> http://cr.openjdk.java.net/~coleenp/2019/8213150.02.incr/webrev
>> full webrev at 
>> http://cr.openjdk.java.net/~coleenp/2019/8213150.02/webrev
>
> Thanks!
>
> /Robbin
>
>>
>> Thanks,
>> Coleen
>>
>>>
>>> Thanks, Robbin
>>>
>>> On 9/20/19 11:36 PM, coleen.phillimore at oracle.com wrote:
>>>> Summary: extend verification for all locking not just VMOperations, 
>>>> and fix CLDG lock to not be taken by VM thread.
>>>>
>>>> See bug comments for more details about this change.
>>>>
>>>> Tested with tier1 all Oracle platforms, tier2-8 linux-x64-debug.
>>>>
>>>> open webrev at 
>>>> http://cr.openjdk.java.net/~coleenp/2019/8213150.01/webrev
>>>> bug link https://bugs.openjdk.java.net/browse/JDK-8213150
>>>>
>>>> Thanks,
>>>> Coleen
>>