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

[Severin Gehwolf]

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
> >>
>