RFR: 8150518: G1 GC crashes at G1CollectedHeap::do_collection_pause_at_safepoint(double)

[Fairoz Matte]

Background:

After the backport of https://bugs.openjdk.java.net/browse/JDK-8017462, The flag -XX:+UseG1GC combined with -XX:ParallelGCThreads=0 makes the _workers to null in 8u. 

As there is no condition to handle such scenario in share/vm/memory/sharedHeap.cpp, which causes the crash.

The similar condition is already implemented for following scenarios

1.       -XX:+UseParallelGC -XX:ParallelGCThreads=0

2.       -XX:+UseParNewGC -XX:ParallelGCThreads=0

3.       -XX:+UseConcMarkSweepGC -XX:ParallelGCThreads=0

 

Fix:

Condition check is added in src/share/vm/runtime/arguments.cpp file to verify "-XX:+UseG1GC -XX:ParallelGCThreads=0"

Thanks for the base patch from Jon.

Due to this patch it makes some of the test cases absolute. They have been removed.

 

Bug: https://bugs.openjdk.java.net/browse/JDK-8150518

Webrev:  http://cr.openjdk.java.net/~rpatil/8150518/webrev.00/

 

Tests: JPRT: HYPERLINK "http://scaaa637.us.oracle.com/archive/2016/03/2016-03-09-082041.fmatte.jdk8u-dev/JobStatus.txt"http://scaaa637.us.oracle.com//archive/2016/03/2016-03-09-082041.fmatte.jdk8u-dev//JobStatus.txt

            JTREG - No issues found