Review-Request: Fix of JDK-8034775 neglects to account for non-JIT VMs

[Vladimir Kozlov]

Hi Albert,

Based on resent mail from Mark we need to publish webrev on our cr. 
server. Severin sent v2 version and I asked if it is final. Albert if it 
is final, please, prepare webrev and send official RFR in format we use.

Thanks,
Vladimir

On 4/29/14 11:47 AM, Albert wrote:
> Iris, thanks for the clarification.
>
> Severin, I will push your changes if they are reviewed.
>
> Thanks,
> Albert
>
>
> On 04/29/2014 06:59 PM, Iris Clark wrote:
>> Hi, Severin.
>>
>>> I work for Red Hat and I believe it has signed the OCA as a company.
>>> Not sure if this makes me a contributor.
>> You're a Contributor.
>>
>> Red Hat is on the Signatories List [1].
>>
>> Thanks,
>> iris
>>
>> [1]: http://www.oracle.com/technetwork/community/oca-486395.html
>>
>> -----Original Message-----
>> From: Severin Gehwolf [mailto:sgehwolf at redhat.com]
>> Sent: Tuesday, April 29, 2014 2:31 AM
>> To: hotspot-dev at openjdk.java.net
>> Subject: Re: Review-Request: Fix of JDK-8034775 neglects to account
>> for non-JIT VMs
>>
>> Hi Albert,
>>
>> On Tue, 2014-04-29 at 10:36 +0200, Albert wrote:
>>> Hi,
>>>
>>> sorry, it was my change that introduced the bug. The change looks good
>>> to me as well.
>> Thanks for looking at the patch!
>>
>>> However, I am not a reviewer, so I think a second review would be good.
>> OK.
>>
>>> Or is the change
>>> simple enough that 1 review is fine? I am not sure.
>>>
>>> Are you a contributor? ( http://openjdk.java.net/contribute/ ) If yes,
>>> I will push your changes as soon as I have an OK.
>> I work for Red Hat and I believe it has signed the OCA as a company.
>> Not sure if this makes me a contributor.
>>
>> Cheers,
>> Severin
>>
>>> On 04/28/2014 08:13 PM, Vladimir Kozlov wrote:
>>>> Hi Severin,
>>>>
>>>> Your fix looks reasonable.
>>>>
>>>> Sorry for breaking your build. I assigned the bug to Albert. He will
>>>> sponsor your changes.
>>>>
>>>> Thanks,
>>>> Vladimir
>>>>
>>>> On 4/28/14 4:42 AM, Severin Gehwolf wrote:
>>>>> Hi,
>>>>>
>>>>> Bug: JI-9011998 (I don't seem to be able to create JDK bugs)
>>>>> Webrev: http://jerboaa.fedorapeople.org/bugs/openjdk/JI-9011998/v1/
>>>>>
>>>>> The fix for JDK-8034775 introduced a start-up check requiring the
>>>>> number of compiler threads to be >= 1, which does not make sense
>>>>> for non-JIT VMs such as the zero JVM variant. This causes zero JVMs
>>>>> to fail initialization with:
>>>>>
>>>>> CICompilerCount of 0 is invalid; must be at least 1
>>>>> Error: Could not create the Java Virtual Machine.
>>>>> Error: A fatal exception has occurred. Program will exit.
>>>>>
>>>>> This is caused by a wrong start-up check in
>>>>> src/share/vm/runtime/arguments.cpp where a minimal value of 1 is
>>>>> required no matter the JVM variant.
>>>>>
>>>>> The proposed fix uses the defined CI_COMPILER_COUNT pre-processor
>>>>> constant over a static 1 to pass to verify_min_value(). Since
>>>>> CI_COMPILER_COUNT is going to be defined differently for JVM
>>>>> variants it will make the lower water mark check correct for all
>>>>> JVM variants.
>>>>>
>>>>> There was an error in defining CI_COMPILER_COUNT as well. On line
>>>>> 196 in src/share/vm/runtime/globals.hpp CI_COMPILER_COUNT is
>>>>> defined to be 0 (since COMPILER1, COMPILER2 and SHARK are not
>>>>> defined for a Zero build.
>>>>> Then on line 201 in src/share/vm/runtime/globals.hpp the "else"
>>>>> branch of ifdef COMPILER2 is entered and the earlier definition of
>>>>> CI_COMPILER_COUNT (with value 0) overridden to 1.
>>>>>
>>>>> I've amended test/compiler/startup/NumCompilerThreadsCheck.java so
>>>>> as to verify that the lower water mark for Zero JVMs is 0.
>>>>>
>>>>> Thoughts?
>>>>>
>>>>> Cheers,
>>>>> Severin
>>>>>
>>
>>
>