RFR: JDK-8260282: Add option to compress heap dumps created by -XX:+HeapDumpOnOutOfMemoryError [v2]

[Ralf Schmelter]

On Mon, 25 Jan 2021 19:15:56 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> Ralf Schmelter 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 six additional commits since the last revision:
>> 
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8260282
>>  - Fixed maximum supported compression level.
>>  - Fixed trailing whitespace.
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8260282
>>  - Change allowed levels. 0 now means disabled.#
>>  - Added option to compress the heap dump created by -XX:+HeapDumpOnOutOfMemoryError
>
> src/hotspot/share/runtime/globals.hpp line 561:
> 
>> 559:           "level of the dump file. 0 (the default) disables gzip "          \
>> 560:           "compression. Otherwise the level must be between 1 and 10.")     \
>> 561:           range(0, 10)                                                      \
> 
> Isn't the range 0-9? Although `HeapDumper::dump()` imposes no upper limit (it seems it should), the `HeapDumpDCMD` sets the upper limit to 9. See `HeapDumpDCmd::execute()`.

You're right. 9 is the maximum compression level supported by zlib. I will update the PR.

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PR: https://git.openjdk.java.net/jdk/pull/2222