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

Tue, 13 Apr 2010 13:52:10 -0700

author
jmasa
date
Tue, 13 Apr 2010 13:52:10 -0700
changeset 1822
0bfd3fb24150
parent 1752
d4197f8d516a
child 1907
c18cbe5936b8
permissions
-rw-r--r--

6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
Summary: Ensure a full GC that clears SoftReferences before throwing an out-of-memory
Reviewed-by: ysr, jcoomes

     1 /*
     2  * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 class ObjectClosure;
    26 class JavaThread;
    28 // A ptrQueue whose elements are "oops", pointers to object heads.
    29 class ObjPtrQueue: public PtrQueue {
    30 public:
    31   ObjPtrQueue(PtrQueueSet* qset_, bool perm = false) :
    32     PtrQueue(qset_, perm, qset_->is_active()) { }
    33   // Apply the closure to all elements, and reset the index to make the
    34   // buffer empty.
    35   void apply_closure(ObjectClosure* cl);
    37   // Apply the closure to all elements of "buf", down to "index" (inclusive.)
    38   static void apply_closure_to_buffer(ObjectClosure* cl,
    39                                       void** buf, size_t index, size_t sz);
    41   void verify_oops_in_buffer() NOT_DEBUG_RETURN;
    42 };
    46 class SATBMarkQueueSet: public PtrQueueSet {
    47   ObjectClosure* _closure;
    48   ObjectClosure** _par_closures;  // One per ParGCThread.
    50   ObjPtrQueue _shared_satb_queue;
    52   // Utility function to support sequential and parallel versions.  If
    53   // "par" is true, then "worker" is the par thread id; if "false", worker
    54   // is ignored.
    55   bool apply_closure_to_completed_buffer_work(bool par, int worker);
    57 #ifdef ASSERT
    58   void dump_active_values(JavaThread* first, bool expected_active);
    59 #endif // ASSERT
    61 public:
    62   SATBMarkQueueSet();
    64   void initialize(Monitor* cbl_mon, Mutex* fl_lock,
    65                   int process_completed_threshold,
    66                   Mutex* lock);
    68   static void handle_zero_index_for_thread(JavaThread* t);
    70   // Apply "set_active(b)" to all Java threads' SATB queues. It should be
    71   // called only with the world stopped. The method will assert that the
    72   // SATB queues of all threads it visits, as well as the SATB queue
    73   // set itself, has an active value same as expected_active.
    74   void set_active_all_threads(bool b, bool expected_active);
    76   // Register "blk" as "the closure" for all queues.  Only one such closure
    77   // is allowed.  The "apply_closure_to_completed_buffer" method will apply
    78   // this closure to a completed buffer, and "iterate_closure_all_threads"
    79   // applies it to partially-filled buffers (the latter should only be done
    80   // with the world stopped).
    81   void set_closure(ObjectClosure* closure);
    82   // Set the parallel closures: pointer is an array of pointers to
    83   // closures, one for each parallel GC thread.
    84   void set_par_closure(int i, ObjectClosure* closure);
    86   // If there is a registered closure for buffers, apply it to all entries
    87   // in all currently-active buffers.  This should only be applied at a
    88   // safepoint.  (Currently must not be called in parallel; this should
    89   // change in the future.)
    90   void iterate_closure_all_threads();
    91   // Parallel version of the above.
    92   void par_iterate_closure_all_threads(int worker);
    94   // If there exists some completed buffer, pop it, then apply the
    95   // registered closure to all its elements, and return true.  If no
    96   // completed buffers exist, return false.
    97   bool apply_closure_to_completed_buffer() {
    98     return apply_closure_to_completed_buffer_work(false, 0);
    99   }
   100   // Parallel version of the above.
   101   bool par_apply_closure_to_completed_buffer(int worker) {
   102     return apply_closure_to_completed_buffer_work(true, worker);
   103   }
   105   ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
   107   // If a marking is being abandoned, reset any unprocessed log buffers.
   108   void abandon_partial_marking();
   110 };

mercurial