hg: jdk7/hotspot-gc/hotspot: 2 new changesets

[antonios.printezis at sun.com]

Changeset: 72f725c5a7be
Author:    tonyp
Date:      2010-04-05 12:19 -0400
URL:       http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/72f725c5a7be

6940310: G1: MT-unsafe calls to CM::region_stack_push() / CM::region_stack_pop()
Summary: Calling the methods region_stack_push() and region_stack_pop() concurrent is not MT-safe. The assumption is that we will only call region_stack_push() during a GC pause and region_stack_pop() during marking. Unfortunately, we also call region_stack_push() during marking which seems to be introducing subtle marking failures. This change introduces lock-based methods for pushing / popping to be called during marking.
Reviewed-by: iveresov, johnc

! src/share/vm/gc_implementation/g1/concurrentMark.cpp
! src/share/vm/gc_implementation/g1/concurrentMark.hpp
! src/share/vm/runtime/mutexLocker.cpp
! src/share/vm/runtime/mutexLocker.hpp

Changeset: 23b1b27ac76c
Author:    tonyp
Date:      2010-04-06 10:59 -0400
URL:       http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/23b1b27ac76c

6909756: G1: guarantee(G1CollectedHeap::heap()->mark_in_progress(),"Precondition.")
Summary: Make sure that two marking cycles do not overlap, i.e., a new one can only start after the concurrent marking thread finishes all its work. In the fix I piggy-back a couple of minor extra fixes: some general code reformatting for consistency (only around the code I modified), the removal of a field (G1CollectorPolicy::_should_initiate_conc_mark) which doesn't seem to be used at all (it's only set but never read), as well as moving the "is GC locker active" test earlier into the G1 pause / Full GC and using a more appropriate method for it.
Reviewed-by: johnc, jmasa, jcoomes, ysr

! src/share/vm/gc_implementation/g1/concurrentMark.cpp
! src/share/vm/gc_implementation/g1/concurrentMarkThread.hpp
! src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
! src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp
! src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp