RFR: 8369147: Various issues with new tests added by JDK-8316694

[Chad Rakoczy]

On Mon, 6 Oct 2025 20:13:46 GMT, Chad Rakoczy <duke at openjdk.org> wrote:

> [JDK-8369147](https://bugs.openjdk.org/browse/JDK-8369147)
> 
> Fixes tests added in [JDK-8316694](https://bugs.openjdk.org/browse/JDK-8316694)
> 
> `DeoptimizeRelocatedNMethod.java` and `RelocateNMethod.java` failed because they attempted to relocate nmethods to the `MethodProfiled` code heap which does not exist when `TieredCompilation` is false. Updated the tests to use `MethodNonProfiled` heap which exists regardless of `TieredCompilation`
> 
> `StressNMethodRelocation.java` runs for 60 seconds and also compiles 1024 methods with C2. This was causing the test to timeout if the compilation took too much time. Increasing the timeout to 5 minutes should give C2 enough time to compile the functions
> 
> `NMethodRelocationTest.java` runs using SerialGC which caused a multiple GC error when trying to run with another GC. Added a requires to force SerialGC

The following occurs when running DeoptimizeRelocatedNMethod on PPC64

#  Internal Error (jdk/src/hotspot/cpu/ppc/nativeInst_ppc.cpp:405)
#  assert(!decode(i1, i2)) failed: already patched

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x1701784]  NativePostCallNop::patch(int, int)+0xf4  (nativeInst_ppc.cpp:405)
V  [libjvm.so+0x1718414]  nmethod::finalize_relocations()+0x6f4  (nmethod.cpp:2059)
V  [libjvm.so+0x171891c]  nmethod::post_init()+0x5c  (nmethod.cpp:1252)
V  [libjvm.so+0x171a8dc]  nmethod::relocate(CodeBlobType)+0x1ec  (nmethod.cpp:1515)
V  [libjvm.so+0x200b598]  WB_RelocateNMethodFromMethod+0x388  (whitebox.cpp:1653)
j  jdk.test.whitebox.WhiteBox.relocateNMethodFromMethod0(Ljava/lang/reflect/Executable;I)V+0
j  jdk.test.whitebox.WhiteBox.relocateNMethodFromMethod(Ljava/lang/reflect/Executable;I)V+8
j  compiler.whitebox.DeoptimizeRelocatedNMethod.main([Ljava/lang/String;)V+50


@TheRealMDoerr @reinrich Do you have any ideas on a solution for this? I don't have any experience working with PPC so guidance would be greatly appreciated

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PR Comment: https://git.openjdk.org/jdk/pull/27659#issuecomment-3403992989