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

Erik Österlund erik.osterlund at oracle.com
Tue Nov 19 08:13:38 UTC 2019

Hi Per,

Looks good.


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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