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

[Zhengyu Gu]

On Fri, 25 Feb 2022 07:33:55 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

Just a minor suggestion. Otherwise, looks good.

src/hotspot/os/linux/os_linux.cpp line 2169:

> 2167: #endif // __GLIBC__
> 2168: 
> 2169: #ifdef __GLIBC__

You can merge these two `#ifdef __GLIBC__` blocks.

-------------

Marked as reviewed by zgu (Reviewer).

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