RFR: 8148507: [JVMCI] mitigate deadlocks related to JVMCI compiler under -Xbatch

[Doug Simon]

> On 08 Feb 2016, at 01:24, David Holmes <David.Holmes at oracle.com> wrote:
> 
> On 6/02/2016 2:34 AM, Christian Thalinger wrote:
>> Looks good to me.  David, any comments?
> 
> Just two observations:
> 
> 1. The methods_compiler counter could overflow. That won't affect the progress check but I don't know if it impacts any other code that uses it.

The only other code using this counter is the progress meter that is part of -XX:+BootstrapJVMCI. Overflow will never happen here (and wouldn’t matter if it did).
> 
> 2. wait_for_jvmci_completion can still fail to return for arbitrarily long periods of time if compilation progresses but at a very slow rate.

Yes, that’s unfortunately unavoidable. But as mentioned elsewhere, -Xbatch is a "best effort” VM option.

Thanks for the review.

-Doug

>>> On Feb 4, 2016, at 12:36 PM, Doug Simon <doug.simon at oracle.com> wrote:
>>> 
>>> I’ve updated the webrev in situ for reasons discussed here:
>>> 
>>> https://bugs.openjdk.java.net/browse/JDK-8148507?focusedCommentId=13896252&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13896252
>>> 
>>> 
>>>> On 03 Feb 2016, at 20:42, Christian Thalinger <christian.thalinger at oracle.com> wrote:
>>>> 
>>>> There was some discussion in the bug report but I seems like we are going to integrate this change.
>>>> 
>>>>> On Jan 31, 2016, at 5:48 AM, Christian Thalinger <christian.thalinger at oracle.com> wrote:
>>>>> 
>>>>> Looks good.
>>>>> 
>>>>>> On Jan 29, 2016, at 4:34 PM, Doug Simon <doug.simon at oracle.com> wrote:
>>>>>> 
>>>>>> Please review this small change to further mitigate deadlocks that can be caused by JVMCI when BackgroundCompilation is disabled.
>>>>>> 
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8148507
>>>>>> http://cr.openjdk.java.net/~dnsimon/8148507
>>>>>> 
>>>>>> -Doug
>>>>> 
>>>> 
>>> 
>>