RFR(XS): 8193521: glibc wastes memory with default configuration

Andrew Dinn adinn at redhat.com
Thu Dec 14 16:27:22 UTC 2017

Hi Martin,

On 14/12/17 16:00, Doerr, Martin wrote:
> I suggest to use mallopt(M_ARENA_MAX, 1). It is supported since glibc
> 2.15. I don't think that we still support older versions with
> jdk10/11.

 . . .

> I'm not aware of performance critical concurrent malloc usages in the
> JVM. Maybe somebody else is? Comments are welcome. I will also need a
> sponsor if this change is desired.

I appreciate the motivation for proposing this and I don't know of any
issues it might cause for the JVM itself. However, it might cause
problems for some of the libraries the JVM links or, indeed, for Java
apps that employ their own native libraries. The former risk could, in
theory, be assessed. The latter one is unquantifiable but needs to be
taken seriously. So, I think this change is probably not safe.


Andrew Dinn
Senior Principal Software Engineer
Red Hat UK Ltd
Registered in England and Wales under Company Registration No. 03798903
Directors: Michael Cunningham, Michael ("Mike") O'Neill, Eric Shander

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