hg: jdk7/hotspot-gc/hotspot: 6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time

[y.s.ramakrishna at oracle.com]

Changeset: c99c53f07c14
Author:    ysr
Date:      2010-09-29 16:17 -0700
URL:       http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/c99c53f07c14

6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
Summary: Inserted missing yield(check)s in closures used during the work-stealing phase of parallel concurrent marking, a missing synchronous yield-request in the cms perm gen allocation path, and a terminator-terminator for the offer_termination invocation that monitors the yield status of the concurrent marking task. Elaborated some documentation comments and made some task queue termination loop flags configurable at start-up to aid debugging in the field.
Reviewed-by: jmasa, johnc, poonam

! src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
! src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp
! src/share/vm/runtime/globals.hpp
! src/share/vm/utilities/yieldingWorkgroup.hpp