src/share/vm/gc_implementation/g1/g1Allocator.cpp

rev 7324 : 8065358: Refactor G1s usage of save_marks and reduce related races
Summary: Stop using save_marks in G1 related code and make setting the replacement field less racy.
Reviewed-by:

*** 57,67 ****
    if (retained_region != NULL &&
        !retained_region->in_collection_set() &&
        !(retained_region->top() == retained_region->end()) &&
        !retained_region->is_empty() &&
        !retained_region->is_humongous()) {
!     retained_region->record_top_and_timestamp();
      // The retained region was added to the old region set when it was
      // retired. We have to remove it now, since we don't allow regions
      // we allocate to in the region sets. We'll re-add it later, when
      // it's retired again.
      _g1h->_old_set.remove(retained_region);
--- 57,67 ----
    if (retained_region != NULL &&
        !retained_region->in_collection_set() &&
        !(retained_region->top() == retained_region->end()) &&
        !retained_region->is_empty() &&
        !retained_region->is_humongous()) {
!     retained_region->record_timestamp();
      // The retained region was added to the old region set when it was
      // retired. We have to remove it now, since we don't allow regions
      // we allocate to in the region sets. We'll re-add it later, when
      // it's retired again.
      _g1h->_old_set.remove(retained_region);
*** 92,101 ****
--- 92,104 ----
    // _retained_old_gc_alloc_region. If we don't
    // _retained_old_gc_alloc_region will become NULL. This is what we
    // want either way so no reason to check explicitly for either
    // condition.
    _retained_old_gc_alloc_region = old_gc_alloc_region(context)->release();
+   if (_retained_old_gc_alloc_region != NULL) {
+     _retained_old_gc_alloc_region->record_retained_region();
+   }
  
    if (ResizePLAB) {
      _g1h->_survivor_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
      _g1h->_old_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
    }