RFR: 8234382: Test tools/javac/processing/model/testgetallmembers/Main.java using too small heap

Per Liden per.liden at oracle.com
Tue Nov 19 08:33:17 UTC 2019

Thanks Erik!


On 11/19/19 9:13 AM, Erik Österlund wrote:
> Hi Per,
> Looks good.
> Thanks,
> /Erik
> On 2019-11-19 08:32, Per Liden wrote:
>> Hi,
>> Please review this one-liner test fix.
>> The test tools/javac/processing/model/testgetallmembers/Main.java is 
>> assuming that a 256M heap is enough to hold its live-set, but this is 
>> only true under some conditions. There are a number of JVM flags that, 
>> when used, can break this assumption. For example, choice of GC, 
>> compressed oop, object alignment, and other options affecting the heap 
>> layout or allocation strategy. Under ideal conditions, the test is 
>> already fairly close to using the whole heap, so it doesn't take that 
>> much to push it over the edge. For example, the following combinations 
>> all fail:
>> -XX:+UseSerialGC -XX:-UseCompressedOops
>> -XX:+UseParallelGC -XX:-UseCompressedOops
>> -XX:+UseZGC (always has -XX:-UseCompressedOops)
>> -XX:+UseG1GC -XX:-UseCompressedOops -XX:ObjectAlignmentInBytes=16
>> I suggest we bump the max heap size to something like 512M, to give 
>> the test more headroom and make it less sensitive to exact choice of 
>> JVM flags.
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8234382
>> Webrev: http://cr.openjdk.java.net/~pliden/8234382/webrev.0
>> /Per

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