RFR: JDK-8282382: Report glibc malloc tunables in error reports [v2]

[David Holmes]

On Wed, 2 Mar 2022 09:56:36 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> On Linux/glibc platforms, the hs-err file should report the malloc tunables, or at least MALLOC_ARENA_MAX, since that one can have a significant effect on footprint or malloc contention for a VM.
>> 
>> This patch adds this printout as a one-liner into hs-err files and jcmd VM.info reports:
>> 
>> 
>> Process Memory:                                                                    
>> ...
>> glibc malloc tunables: MALLOC_PERTURB_=40, MALLOC_ARENA_MAX=1
>> 
>> 
>> If the tunables are default, we print `glibc malloc tunables: (default)`.
>> 
>> 
>> Thanks, Thomas
>
> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Zhengyus feedback, comment fixes, added SAP copyright

Seems okay. One minor query.

Thanks,
David

src/hotspot/os/linux/os_linux.cpp line 2120:

> 2118:   if (!printed) {
> 2119:     st->print("(default)");
> 2120:   }

else st->cr()? Rather than adding the cr() externally.

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/7620