RFR 8204552: NMT: Separate thread stack tracking from virtual memory tracking

[zgu at redhat.com]

Friendly ping!

Thanks,

-Zhengyu

On Mon, 2019-02-18 at 14:57 -0500, zgu at redhat.com wrote:
> On Mon, 2019-02-18 at 08:50 -0500, zgu at redhat.com wrote:
> > NMT tracks thread stacks as virtual memory since day one, as most
> > of
> > platofrms are using virtual memory to back thread stacks. However,
> > there are exceptions, e.g. AIX. The matter of fact, POSIX standard
> > does
> > not dictate what kind of memory or even alignment requirement for
> > thread stacks.
> > 
> > This patch separates thread stack tracking from virtual memory
> > tracking. It delegates to virtual memory tracker if thread stack is
> > backed by virtual memory.
> > 
> > For thread stacks that are backed by malloc'd memory, it can not
> > simply
> > utilize malloc tracker for detail tracking, since it can not
> > install
> > tracking header in place. Therefore, it has to track those memory
> > separately, then piggybacks to existing malloc tracking
> > infrastructure
> > during snapshot, for baselining and reporting.
> > 
> > Thanks for Goetz Lindenmaier and Thomas Stüfe's help to run the
> > patch
> > through SAP buidling and testing infrastructure, that is especially
> > helpful for verifying the fix for AIX.
> > 
> > 
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8204552
> > Webrev: http://cr.openjdk.java.net/~zgu/JDK-8204552/webrev.01/
> > 
> > Test:
> >   hotspot_nmt on Linux x64 (fastdebug and release)
> 
> Also passed JDK-submit tests.
> 
> Thanks,
> 
> -Zhengyu
> 
> > 
> > Thanks,
> > 
> > -Zhengyu
> > 
> > 
> >