src/share/vm/gc/g1/g1CollectedHeap.hpp

rev 8687 : 8004687: G1: Parallelize object self-forwarding and scanning during an evacuation failure
Summary: Use the regular task queue during evacuation failure and allow per-thread preserved header queues to remove the global lock during evacuation failure.
Reviewed-by:
Contributed-by: Walter Florian Gugenberger <walter.gugenberger@gmail.com>

*** 856,903 ****
  
    // Failed evacuations cause some logical from-space objects to have
    // forwarding pointers to themselves.  Reset them.
    void remove_self_forwarding_pointers();
  
!   // Together, these store an object with a preserved mark, and its mark value.
!   Stack<oop, mtGC>     _objs_with_preserved_marks;
!   Stack<markOop, mtGC> _preserved_marks_of_objs;
! 
!   // Preserve the mark of "obj", if necessary, in preparation for its mark
!   // word being overwritten with a self-forwarding-pointer.
!   void preserve_mark_if_necessary(oop obj, markOop m);
  
!   // The stack of evac-failure objects left to be scanned.
!   GrowableArray<oop>*    _evac_failure_scan_stack;
!   // The closure to apply to evac-failure objects.
! 
!   OopsInHeapRegionClosure* _evac_failure_closure;
!   // Set the field above.
!   void
!   set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) {
!     _evac_failure_closure = evac_failure_closure;
    }
  
!   // Push "obj" on the scan stack.
!   void push_on_evac_failure_scan_stack(oop obj);
!   // Process scan stack entries until the stack is empty.
!   void drain_evac_failure_scan_stack();
!   // True iff an invocation of "drain_scan_stack" is in progress; to
!   // prevent unnecessary recursion.
!   bool _drain_in_progress;
! 
!   // Do any necessary initialization for evacuation-failure handling.
!   // "cl" is the closure that will be used to process evac-failure
!   // objects.
!   void init_for_evac_failure(OopsInHeapRegionClosure* cl);
!   // Do any necessary cleanup for evacuation-failure handling data
!   // structures.
!   void finalize_for_evac_failure();
! 
!   // An attempt to evacuate "obj" has failed; take necessary steps.
!   oop handle_evacuation_failure_par(G1ParScanThreadState* _par_scan_state, oop obj);
!   void handle_evacuation_failure_common(oop obj, markOop m);
  
  #ifndef PRODUCT
    // Support for forcing evacuation failures. Analogous to
    // PromotionFailureALot for the other collectors.
  
--- 856,886 ----
  
    // Failed evacuations cause some logical from-space objects to have
    // forwarding pointers to themselves.  Reset them.
    void remove_self_forwarding_pointers();
  
!   struct OopAndMarkOop {
!    private:
!     oop _o;
!     markOop _m;
!    public:
!     OopAndMarkOop(oop obj, markOop m) : _o(obj), _m(m) {
!     }
  
!     void set_mark() {
!       _o->set_mark(_m);
      }
+   };
    
!   typedef Stack<OopAndMarkOop,mtGC> OopAndMarkOopStack;
!   // Stores marks with the corresponding oop that we need to preserve during evacuation
!   // failure.
!   OopAndMarkOopStack*  _preserved_objs;
! 
!   // Preserve the mark of "obj", if necessary, in preparation for its mark
!   // word being overwritten with a self-forwarding-pointer.
!   void preserve_mark_during_evac_failure(uint queue, oop obj, markOop m);
  
  #ifndef PRODUCT
    // Support for forcing evacuation failures. Analogous to
    // PromotionFailureALot for the other collectors.