hg: jdk7/hotspot-gc/hotspot: 6994297: G1: do first-level slow-path allocations with a CAS

[tony.printezis at oracle.com]

Changeset: b158bed62ef5
Author:    tonyp
Date:      2011-01-12 16:34 -0500
URL:       http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/b158bed62ef5

6994297: G1: do first-level slow-path allocations with a CAS
Summary: First attempt to allocate out the current alloc region using a CAS instead of taking the Heap_lock (first level of G1's slow allocation path). Only if that fails and it's necessary to replace the current alloc region take the Heap_lock (that's the second level of G1's slow allocation path).
Reviewed-by: johnc, brutisso, ysr

! src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
! src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
! src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp
! src/share/vm/gc_implementation/g1/heapRegion.hpp