RFR: JDK-8293114: JVM should trim the native heap [v10]

[Thomas Stuefe]

On Fri, 14 Jul 2023 05:02:34 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Bikeshed Trim log lines
>
> test/hotspot/gtest/runtime/test_trim_native.cpp line 44:
> 
>> 42:       NativeHeapTrimmer::SuspendMark sm2("Test2");
>> 43:       {
>> 44:         NativeHeapTrimmer::SuspendMark sm3("Test3");
> 
> What is this actually testing? Everything could be a no-op.

Whether it blows up or not with internal asserts that test suspend count overflow.

But you are right; this raises another issue. One is that this is never tested since we need a gtest variant running with native trimming enabled. Another is that we need a printout of the trim state, at least for VMError::report, and that could be used here too to check the expected suspend count.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14781#discussion_r1263344482