[9] RFR (M): 8050486: compiler/rtm/ tests fail due to monitor deflation at safepoint synchronization

[Filipp Zhinkin]

Vladimir, thank you for review!

Regards,
Filipp.

----- Original Message -----
From: vladimir.kozlov at oracle.com
To: hotspot-compiler-dev at openjdk.java.net
Sent: Tuesday, December 30, 2014 1:12:06 AM GMT +03:00 Iraq
Subject: Re: [9] RFR (M): 8050486: compiler/rtm/ tests fail due to monitor deflation at safepoint synchronization

On 12/29/14 12:27 PM, Filipp Zhinkin wrote:
> Hi Vladimir,
>
> thank you for looking at it.
>
> The second thread (which is started in line 75) enters the monitor first.
> It is guaranteed by a barrier.
>
> When the barrier passed, the second thread calls wait() on the monitor
> and thus inflate and release it.
>
> The first thread then may enter the monitor in line 78.

Got it. Reviewed.

Thanks,
Vladimir

>
> Thanks,
> Filipp.
>
> ----- Original Message -----
> From: vladimir.kozlov at oracle.com
> To: hotspot-compiler-dev at openjdk.java.net
> Sent: Monday, December 29, 2014 10:37:16 PM GMT +03:00 Iraq
> Subject: Re: [9] RFR (M): 8050486: compiler/rtm/ tests fail due to monitor deflation at safepoint synchronization
>
> Filipp,
>
> I don't understand how you expect progress in lines 78-83 in
> AbortProvoker.java when second thread keeps lock of 'monitor'.
> synchronized (monitor) at the line 78 should wait until second thread
> release it so you will never reach line 83.
>
> I would suggest to lunch third thread to inflate monitor and use main
> thread to see the state.
>
> Thanks,
> Vladimir
>
> On 12/29/14 8:35 AM, Filipp Zhinkin wrote:
>> Hi all,
>>
>> please review a fix for JDK-8050486.
>>
>> Following issues cause compiler/rtm/ tests failures
>> when safepoint sync happened in the middle of test run:
>> - monitors that expected to be inflated are deflated;
>> - monitors that expected to be lightweight stack-locks are inflated.
>>
>> In order to solve the first issue inflation-forcing algorithm
>> was modified to wait forever on a monitor that should be inflated.
>>
>> The second issue is resolved by explicit monitor state checks that
>> force deflation in case when monitor is inflated, but it should not.
>>
>> This fix depends on 8068272:
>> http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2014-December/016744.html
>>
>> Bug id: https://bugs.openjdk.java.net/browse/JDK-8050486
>> Webrev: http://cr.openjdk.java.net/~fzhinkin/8050486/webrev.00/
>> Testing: on host w/ HSW CPU, JPRT, automated on hosts w/ HSW CPU.
>>
>> Thanks,
>> Filipp.
>>