[8u] RFR: 8201495: [Zero] Reduce limits of max heap size for boot JDK on s390

[Severin Gehwolf]

Hi,

Could I please get a review for a fix which went into JDK 11 already.
It reduces the maximum heap requirement for 32bit builds, which breaks
s390 (31 bit) builds:

+ /usr/lib/jvm/java-openjdk/bin/java -Xms64M -Xmx1100M -XX:ThreadStackSize=768 -XX:PermSize=32m -XX:MaxPermSize=160m -Xbootclasspath/p:/builddir/build/BUILD/java-1.8.0-openjdk-1.8.0.171-8.b10.el7.s390/openjdk/build/jdk8.build/langtools/dist/bootstrap/lib/javac.jar -classpath /builddir/build/BUILD/java-1.8.0-openjdk-1.8.0.171-8.b10.el7.s390/openjdk/build/jdk8.build/langtools/btclasses genstubs.GenStubs -s /builddir/build/BUILD/java-1.8.0-openjdk-1.8.0.171-8.b10.el7.s390/openjdk/build/jdk8.build/langtools/tmpstubs -sourcepath /builddir/build/BUILD/java-1.8.0-openjdk-1.8.0.171-8.b10.el7.s390/openjdk/jdk/src/share/classes java.util.function.Predicate
Error occurred during initialization of VM
Could not reserve enough space for object heap
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
gmake[1]: Leaving directory `/builddir/build/BUILD/java-1.8.0-openjdk-1.8.0.171-8.b10.el7.s390/openjdk/langtools/make'
gmake[1]: *** No rule to make target `all', needed by `default'.  Stop.
make: *** [langtools-only] Error 2

The patch for JDK 11 does not apply cleanly since the build system got
changed. The JDK 8 patch is here:

webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8201495/webrev.jdk8/
Bug:    https://bugs.openjdk.java.net/browse/JDK-8201495
JDK 11 review: http://mail.openjdk.java.net/pipermail/build-dev/2018-April/021754.html

Once this has been reviewed, I'll ask for approval on the jdk8u-dev
list before it gets pushed to JDK 8u.

Thanks,
Severin