hotspot/src/share/vm/gc_implementation/g1/concurrentMark.hpp

rev 7368 : 8075215: SATB buffer processing found reclaimed humongous object
Summary: Don't assume SATB buffer entries are valid objects
Reviewed-by: brutisso, ecaspole

*** 791,808 ****
    void note_end_of_gc() {
      _markStack.note_end_of_gc();
    }
  
    // Verify that there are no CSet oops on the stacks (taskqueues /
!   // global mark stack), enqueued SATB buffers, per-thread SATB
!   // buffers, and fingers (global / per-task). The boolean parameters
!   // decide which of the above data structures to verify. If marking
!   // is not in progress, it's a no-op.
!   void verify_no_cset_oops(bool verify_stacks,
!                            bool verify_enqueued_buffers,
!                            bool verify_thread_buffers,
!                            bool verify_fingers) PRODUCT_RETURN;
  
    bool isPrevMarked(oop p) const {
      assert(p != NULL && p->is_oop(), "expected an oop");
      HeapWord* addr = (HeapWord*)p;
      assert(addr >= _prevMarkBitMap->startWord() ||
--- 791,803 ----
    void note_end_of_gc() {
      _markStack.note_end_of_gc();
    }
  
    // Verify that there are no CSet oops on the stacks (taskqueues /
!   // global mark stack) and fingers (global / per-task).
!   // If marking is not in progress, it's a no-op.
!   void verify_no_cset_oops() PRODUCT_RETURN;
  
    bool isPrevMarked(oop p) const {
      assert(p != NULL && p->is_oop(), "expected an oop");
      HeapWord* addr = (HeapWord*)p;
      assert(addr >= _prevMarkBitMap->startWord() ||
*** 1106,1115 ****
--- 1101,1116 ----
    // it checks a bunch of conditions that might cause the marking step
    // to abort
    void regular_clock_call();
    bool concurrent() { return _concurrent; }
  
+   // Test whether obj might have already been passed over by the
+   // mark bitmap scan, and so needs to be pushed onto the mark stack.
+   bool is_below_finger(oop obj, HeapWord* global_finger) const;
+ 
+   template<bool scan> void process_grey_object(oop obj);
+ 
  public:
    // It resets the task; it should be called right at the beginning of
    // a marking phase.
    void reset(CMBitMap* _nextMarkBitMap);
    // it clears all the fields that correspond to a claimed region.
*** 1153,1168 ****
    bool has_timed_out()          { return _has_timed_out; }
    bool claimed()                { return _claimed; }
  
    void set_cm_oop_closure(G1CMOopClosure* cm_oop_closure);
  
!   // It grays the object by marking it and, if necessary, pushing it
!   // on the local queue
    inline void deal_with_reference(oop obj);
  
    // It scans an object and visits its children.
!   void scan_object(oop obj);
  
    // It pushes an object on the local queue.
    inline void push(oop obj);
  
    // These two move entries to/from the global stack.
--- 1154,1179 ----
    bool has_timed_out()          { return _has_timed_out; }
    bool claimed()                { return _claimed; }
  
    void set_cm_oop_closure(G1CMOopClosure* cm_oop_closure);
  
!   // Increment the number of references this task has visited.
!   void increment_refs_reached() { ++_refs_reached; }
! 
!   // Grey the object by marking it.  If not already marked, push it on
!   // the local queue if below the finger.
!   // Precondition: obj is in region.
!   // Precondition: obj is below region's NTAMS.
!   inline void make_reference_grey(oop obj, HeapRegion* region);
! 
!   // Grey the object (by calling make_grey_reference) if required,
!   // e.g. obj is below its containing region's NTAMS.
!   // Precondition: obj is a valid heap object.
    inline void deal_with_reference(oop obj);
  
    // It scans an object and visits its children.
!   void scan_object(oop obj) { process_grey_object<true>(obj); }
  
    // It pushes an object on the local queue.
    inline void push(oop obj);
  
    // These two move entries to/from the global stack.