Code Review request for bug fixes found by the Contended Locking project

Vitaly Davidovich vitalyd at
Thu Jan 17 15:16:56 PST 2013

Hi Dan,

Just curious - what's the reason for adding OrderAccess::fence() after the
pthread_mutex_unlock() calls? Is this working around some libc issues or
something? I'd expect those unlocks to provide the ordering and visibility


Sent from my phone
On Jan 17, 2013 1:46 PM, "Daniel D. Daugherty" <daniel.daugherty at>

> Greetings,
> I have been working on the Contended Locking project and there are some
> bug fixes that I'd like to push into HSX-25 independently of the Contended
> Locking project.
> I'm using three different bug IDs to track these very distinct bug
> fixes:
>     6444286 Possible naked oop related to biased locking revocation
>             safepoint in jni_exit()
>     8004902 correctness fixes motivated by contended locking work (6607129)
>     8004903 VMThread::execute() calls Thread::check_for_valid_**
> safepoint_state()
>             on concurrent VM ops
> Here is the URL for the webrev:
> These changes have been through two internal rounds of code review so I
> think they are ready for wider review. The changes for 8004902 are very
> tricky and there is long write-up attached to the 8004902 bug report that
> explains the intricate details of the "triangular race". The changes for
> 6444286 and 8004903 are more straight forward.
> These changes have been through JPRT build-and-test and have also been
> tested with the vm.parallel_class_loading and vm.quick subsuites via
> the Aurora ad-hoc testing mechanism.
> The current set of reviewers is:
>     acorn, dholmes, dice
> As always, other reviewers are welcome. Comments, questions and
> suggestions are also welcome.
> Dan
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