[aarch64-port-dev ] RFR(s): 8171449" [aarch64] store_klass needs to use store release

Andrew Dinn adinn at redhat.com
Tue Dec 20 10:01:26 UTC 2016

On 19/12/16 21:22, White, Derek wrote:
> As the "FIXME" noted, aarch64 really does need to use a store release
> in the "store_klass" macro, at least when a concurrent GC is in
> effect.
> BUG: https://bugs.openjdk.java.net/browse/JDK-8171449
> Webrev:
> http://cr.openjdk.java.net/~drwhite/8171449/webrev.01/index.html
> BTW, PPC is likely to need a similar fix...

This looks like only half the story. The stlrw is only going to be of
any relevance if code which reads the klass and klass length does so
using a ldarw (n.b. these synchronizing instructions will only be needed
if there is no other guarantee of memory synchronization between any
store and its corresponding load).

Can you point to where in the GC code the corresponding loads occur?


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

More information about the hotspot-runtime-dev mailing list