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

[Albert]

Hi,

sorry, it was my change that introduced the bug. The change looks good 
to me as well.
However, I am not a reviewer, so I think a second review would be good. 
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.

Many thanks,
Albert



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
>>