RFR: 8058176: [mlvm] tests should not allow code cache exhaustion [v2]

[Evgeny Nikitin]

On Tue, 16 Feb 2021 19:49:02 GMT, Igor Ignatyev <iignatyev at openjdk.org> wrote:

>> Thanks for the info about the segmented code cache. I did some research and found that the opposite is true - both nmethod pools ('profiled' and 'non-profiled') are growing along with the MH graph growth. This is supported by the specification for non-method code heap at:
>> 
>> https://docs.oracle.com/en/java/javase/15/vm/java-hotspot-virtual-machine-performance-enhancements.html#GUID-1D9B26AD-8E0A-4771-90DA-A81A2C1F5B55
>> 
>> Please check the the fixed version.
>
> o/c they grow, b/c we use them for compiled code *and* if there is no space in non-nmethod heap, we use them for adapters as well, so I guess that the growth that you see is already after non-nmethod heap got exhausted. I'd recommend you simply use the sum of all available code-heaps (this will increase the possibility of false-positive results due to segmentation, but I don't think it matters much here).

Well, seems like rebalancing doesn't works that good. Here's a sample failure with plenty of free space in the non-nmethods heap:

[8.230s][warning][codecache] CodeHeap 'non-profiled nmethods' is full. Compiler has been disabled.
[8.230s][warning][codecache] Try increasing the code heap size using -XX:NonProfiledCodeHeapSize=
Java HotSpot(TM) 64-Bit Server VM warning: CodeHeap 'non-profiled nmethods' is full. Compiler has been disabled.
Java HotSpot(TM) 64-Bit Server VM warning: Try increasing the code heap size using -XX:NonProfiledCodeHeapSize=
CodeHeap 'non-profiled nmethods': size=8192Kb used=8191Kb max_used=8191Kb free=0Kb   << Exhausted
CodeHeap 'profiled nmethods': size=8192Kb used=8191Kb max_used=8191Kb free=0Kb       << Exhausted
CodeHeap 'non-nmethods': size=102400Kb used=18343Kb max_used=18343Kb free=84056Kb    << 84Mb of free space

# ERROR: Caught exception in Thread[Thread-41,5,MainThreadGroup]
...
# ERROR: Caused by: java.lang.VirtualMachineError: Out of space in CodeCache for method handle intrinsic
The sum monitoring won't help here either. I've added non-nmethods heap to the monitoring, just to be sure.

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PR: https://git.openjdk.java.net/jdk/pull/2523