jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/satbQueue.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/g1/satbQueue.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/g1/satbQueue.hpp

Thu, 22 Sep 2011 10:57:37 -0700

author: johnc
date: Thu, 22 Sep 2011 10:57:37 -0700
changeset 3175: 4dfb2df418f2
parent 2469: 7e37af9d69ef
child 3416: 2ace1c4ee8da
permissions: -rw-r--r--

6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp

 /*
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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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  * published by the Free Software Foundation.
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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
 #include "gc_implementation/g1/ptrQueue.hpp"
 class ObjectClosure;
 class JavaThread;
 // A ptrQueue whose elements are "oops", pointers to object heads.
 class ObjPtrQueue: public PtrQueue {
 public:
   ObjPtrQueue(PtrQueueSet* qset, bool perm = false) :
     // SATB queues are only active during marking cycles. We create
     // them with their active field set to false. If a thread is
     // created during a cycle and its SATB queue needs to be activated
     // before the thread starts running, we'll need to set its active
     // field to true. This is done in JavaThread::initialize_queues().
     PtrQueue(qset, perm, false /* active */) { }
   // Overrides PtrQueue::should_enqueue_buffer(). See the method's
   // definition for more information.
   virtual bool should_enqueue_buffer();
   // Apply the closure to all elements, and reset the index to make the
   // buffer empty.
   void apply_closure(ObjectClosure* cl);
   // Apply the closure to all elements of "buf", down to "index" (inclusive.)
   static void apply_closure_to_buffer(ObjectClosure* cl,
                                       void** buf, size_t index, size_t sz);
   void verify_oops_in_buffer() NOT_DEBUG_RETURN;
 };
 class SATBMarkQueueSet: public PtrQueueSet {
   ObjectClosure* _closure;
   ObjectClosure** _par_closures;  // One per ParGCThread.
   ObjPtrQueue _shared_satb_queue;
   // Utility function to support sequential and parallel versions.  If
   // "par" is true, then "worker" is the par thread id; if "false", worker
   // is ignored.
   bool apply_closure_to_completed_buffer_work(bool par, int worker);
 #ifdef ASSERT
   void dump_active_values(JavaThread* first, bool expected_active);
 #endif // ASSERT
 public:
   SATBMarkQueueSet();
   void initialize(Monitor* cbl_mon, Mutex* fl_lock,
                   int process_completed_threshold,
                   Mutex* lock);
   static void handle_zero_index_for_thread(JavaThread* t);
   // Apply "set_active(b)" to all Java threads' SATB queues. It should be
   // called only with the world stopped. The method will assert that the
   // SATB queues of all threads it visits, as well as the SATB queue
   // set itself, has an active value same as expected_active.
   void set_active_all_threads(bool b, bool expected_active);
   // Register "blk" as "the closure" for all queues.  Only one such closure
   // is allowed.  The "apply_closure_to_completed_buffer" method will apply
   // this closure to a completed buffer, and "iterate_closure_all_threads"
   // applies it to partially-filled buffers (the latter should only be done
   // with the world stopped).
   void set_closure(ObjectClosure* closure);
   // Set the parallel closures: pointer is an array of pointers to
   // closures, one for each parallel GC thread.
   void set_par_closure(int i, ObjectClosure* closure);
   // If there is a registered closure for buffers, apply it to all entries
   // in all currently-active buffers.  This should only be applied at a
   // safepoint.  (Currently must not be called in parallel; this should
   // change in the future.)
   void iterate_closure_all_threads();
   // Parallel version of the above.
   void par_iterate_closure_all_threads(int worker);
   // If there exists some completed buffer, pop it, then apply the
   // registered closure to all its elements, and return true.  If no
   // completed buffers exist, return false.
   bool apply_closure_to_completed_buffer() {
     return apply_closure_to_completed_buffer_work(false, 0);
   }
   // Parallel version of the above.
   bool par_apply_closure_to_completed_buffer(int worker) {
     return apply_closure_to_completed_buffer_work(true, worker);
   }
   ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
   // If a marking is being abandoned, reset any unprocessed log buffers.
   void abandon_partial_marking();
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP

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src/share/vm/gc_implementation/g1/satbQueue.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/g1/satbQueue.hpp