RFR: JDK-8293114: JVM should trim the native heap [v8]

[Thomas Stuefe]

On Mon, 10 Jul 2023 18:50:15 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 32 additional commits since the last revision:
>> 
>>  - Make test spikes more pronounced
>>  - Dont query procfs if logging is off
>>  - rename logtag again
>>  - When probing for safepoint end, use the smaller of (interval, 250ms)
>>  - Remove TrimNativeHeap and expand TrimNativeHeapInterval
>>  - Improve comments for non-supportive platforms
>>  - Aleksey cosmetics
>>  - suspend count return 16 bits
>>  - Fix linker errors
>>  - Merge branch 'master' into JDK-8293114-JVM-should-trim-the-native-heap
>>  - ... and 22 more: https://git.openjdk.org/jdk/compare/0fd1ca68...15566761
>
> src/hotspot/share/runtime/trimNativeHeap.cpp line 47:
> 
>> 45: 
>> 46:   // Statistics
>> 47:   unsigned _num_trims_performed;
> 
> Sorry for the nit, but this is `uint16_t` too then, for consistency?

No, since `_num_trims_performed` is the number of trims performed during the lifetime of the JVM. It should probably bumped to 64-bit, now that we have millisecond intervals.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14781#discussion_r1262877532