RFR: JDK-8268893: jcmd to trim the glibc heap [v2]

[Volker Simonis]

On Mon, 21 Jun 2021 12:26:20 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> _Mailing list message from [David Holmes](mailto:david.holmes at oracle.com) on [hotspot-runtime-dev](mailto:hotspot-runtime-dev at mail.openjdk.java.net):_
> 
> On 21/06/2021 7:58 pm, Thomas Stuefe wrote:
> 
> > On Mon, 21 Jun 2021 09:15:05 GMT, Volker Simonis <simonis at openjdk.org> wrote:
> > > I like this little new diagnostic command which I think can be quite useful in specific situations.
> > 
> > 
> > Thanks a lot Volker!
> > > However, in contrast to other reviewers, I'd rather keep this simple and Glibc specific instead of extending it to a more general but mostly empty command.
> > 
> > 
> > Yes, that was my thought too. Lets wait for @dholmes-ora to chime in, whether we can all agree on a glibc specific variant. I also preferred that one.
> 
> I don't totally oppose the specialised variant, but it certainly isn't
> my ideal solution. Not sure if we already have platform specific dcmds?

Yes, we have. E.g.:

#ifdef LINUX
class PerfMapDCmd : public DCmd {
public:
  PerfMapDCmd(outputStream* output, bool heap) : DCmd(output, heap) {}
  static const char* name() {
    return "Compiler.perfmap";
  }
  static const char* description() {
    return "Write map file for Linux perf tool.";
  }
...


> This will need a CSR request anyway.
> 
> Cheers,
> David

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

PR: https://git.openjdk.java.net/jdk/pull/4510