MMTk 0.13.0

Allocators

• Fixed a bug that in GC stress testing, the allocator slowpath may double count the allocated bytes.
• Fixed a bug that in GC stress testing, the Immix allocator may miss the updates to the allocated bytes in some cases.

Scheduler

• Added work stealing mechanisms to the scheduler: a GC worker may steal work packets from other workers.
• Fixed a bug that work buckets may be incorrectly opened when there is still work left in workers' local bucket.

API

• Added an associate type Finalizable to ReferenceGlue, with which, a binding can define their own finalizer type.
• Added a set of malloc APIs that allows a binding to do malloc using MMTk.
• Added vm_trace_object() to ActivePlan. When tracing an object that is not in any of MMTk spaces, MMTk will call this method
  and allow bindings to handle the object.

Misc

• trait TransitiveClosure is split into two different traits: EdgeVisitor and ObjectQueue, and TransitiveClosure is now removed.
• Fixed a bug that the work packet statistics were not collected correctly if different work packets used the same display name.
• Fixed a bug that the work packet statistics and the phase statistics use different time units. Now they both use milliseconds.
• Fixed a bug that acquire_lock was used to lock a larger scope than what was necessary, which caused bad performance when we have many
  allocation threads (e.g. more than 24 threads).