src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.cpp

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

author
johnc
date
Thu, 22 Sep 2011 10:57:37 -0700
changeset 3175
4dfb2df418f2
parent 2314
f95d63e2154a
child 3294
bca17e38de00
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

     1 /*
     2  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #include "precompiled.hpp"
    26 #include "classfile/systemDictionary.hpp"
    27 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
    28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
    29 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp"
    30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
    31 #include "gc_implementation/parallelScavenge/psCompactionManager.hpp"
    32 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
    33 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
    34 #include "oops/objArrayKlass.inline.hpp"
    35 #include "oops/oop.hpp"
    36 #include "oops/oop.inline.hpp"
    37 #include "oops/oop.pcgc.inline.hpp"
    38 #include "utilities/stack.inline.hpp"
    40 PSOldGen*            ParCompactionManager::_old_gen = NULL;
    41 ParCompactionManager**  ParCompactionManager::_manager_array = NULL;
    42 OopTaskQueueSet*     ParCompactionManager::_stack_array = NULL;
    43 ParCompactionManager::ObjArrayTaskQueueSet*
    44   ParCompactionManager::_objarray_queues = NULL;
    45 ObjectStartArray*    ParCompactionManager::_start_array = NULL;
    46 ParMarkBitMap*       ParCompactionManager::_mark_bitmap = NULL;
    47 RegionTaskQueueSet*  ParCompactionManager::_region_array = NULL;
    49 ParCompactionManager::ParCompactionManager() :
    50     _action(CopyAndUpdate) {
    52   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
    53   assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
    55   _old_gen = heap->old_gen();
    56   _start_array = old_gen()->start_array();
    58   marking_stack()->initialize();
    59   _objarray_stack.initialize();
    60   region_stack()->initialize();
    61 }
    63 void ParCompactionManager::initialize(ParMarkBitMap* mbm) {
    64   assert(PSParallelCompact::gc_task_manager() != NULL,
    65     "Needed for initialization");
    67   _mark_bitmap = mbm;
    69   uint parallel_gc_threads = PSParallelCompact::gc_task_manager()->workers();
    71   assert(_manager_array == NULL, "Attempt to initialize twice");
    72   _manager_array = NEW_C_HEAP_ARRAY(ParCompactionManager*, parallel_gc_threads+1 );
    73   guarantee(_manager_array != NULL, "Could not allocate manager_array");
    75   _stack_array = new OopTaskQueueSet(parallel_gc_threads);
    76   guarantee(_stack_array != NULL, "Could not allocate stack_array");
    77   _objarray_queues = new ObjArrayTaskQueueSet(parallel_gc_threads);
    78   guarantee(_objarray_queues != NULL, "Could not allocate objarray_queues");
    79   _region_array = new RegionTaskQueueSet(parallel_gc_threads);
    80   guarantee(_region_array != NULL, "Could not allocate region_array");
    82   // Create and register the ParCompactionManager(s) for the worker threads.
    83   for(uint i=0; i<parallel_gc_threads; i++) {
    84     _manager_array[i] = new ParCompactionManager();
    85     guarantee(_manager_array[i] != NULL, "Could not create ParCompactionManager");
    86     stack_array()->register_queue(i, _manager_array[i]->marking_stack());
    87     _objarray_queues->register_queue(i, &_manager_array[i]->_objarray_stack);
    88     region_array()->register_queue(i, _manager_array[i]->region_stack());
    89   }
    91   // The VMThread gets its own ParCompactionManager, which is not available
    92   // for work stealing.
    93   _manager_array[parallel_gc_threads] = new ParCompactionManager();
    94   guarantee(_manager_array[parallel_gc_threads] != NULL,
    95     "Could not create ParCompactionManager");
    96   assert(PSParallelCompact::gc_task_manager()->workers() != 0,
    97     "Not initialized?");
    98 }
   100 bool ParCompactionManager::should_update() {
   101   assert(action() != NotValid, "Action is not set");
   102   return (action() == ParCompactionManager::Update) ||
   103          (action() == ParCompactionManager::CopyAndUpdate) ||
   104          (action() == ParCompactionManager::UpdateAndCopy);
   105 }
   107 bool ParCompactionManager::should_copy() {
   108   assert(action() != NotValid, "Action is not set");
   109   return (action() == ParCompactionManager::Copy) ||
   110          (action() == ParCompactionManager::CopyAndUpdate) ||
   111          (action() == ParCompactionManager::UpdateAndCopy);
   112 }
   114 bool ParCompactionManager::should_verify_only() {
   115   assert(action() != NotValid, "Action is not set");
   116   return action() == ParCompactionManager::VerifyUpdate;
   117 }
   119 bool ParCompactionManager::should_reset_only() {
   120   assert(action() != NotValid, "Action is not set");
   121   return action() == ParCompactionManager::ResetObjects;
   122 }
   124 ParCompactionManager*
   125 ParCompactionManager::gc_thread_compaction_manager(int index) {
   126   assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range");
   127   assert(_manager_array != NULL, "Sanity");
   128   return _manager_array[index];
   129 }
   131 void ParCompactionManager::reset() {
   132   for(uint i = 0; i < ParallelGCThreads + 1; i++) {
   133     assert(manager_array(i)->revisit_klass_stack()->is_empty(), "sanity");
   134     assert(manager_array(i)->revisit_mdo_stack()->is_empty(), "sanity");
   135   }
   136 }
   138 void ParCompactionManager::follow_marking_stacks() {
   139   do {
   140     // Drain the overflow stack first, to allow stealing from the marking stack.
   141     oop obj;
   142     while (marking_stack()->pop_overflow(obj)) {
   143       obj->follow_contents(this);
   144     }
   145     while (marking_stack()->pop_local(obj)) {
   146       obj->follow_contents(this);
   147     }
   149     // Process ObjArrays one at a time to avoid marking stack bloat.
   150     ObjArrayTask task;
   151     if (_objarray_stack.pop_overflow(task)) {
   152       objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
   153       k->oop_follow_contents(this, task.obj(), task.index());
   154     } else if (_objarray_stack.pop_local(task)) {
   155       objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
   156       k->oop_follow_contents(this, task.obj(), task.index());
   157     }
   158   } while (!marking_stacks_empty());
   160   assert(marking_stacks_empty(), "Sanity");
   161 }
   163 void ParCompactionManager::drain_region_stacks() {
   164   do {
   165     // Drain overflow stack first so other threads can steal.
   166     size_t region_index;
   167     while (region_stack()->pop_overflow(region_index)) {
   168       PSParallelCompact::fill_and_update_region(this, region_index);
   169     }
   171     while (region_stack()->pop_local(region_index)) {
   172       PSParallelCompact::fill_and_update_region(this, region_index);
   173     }
   174   } while (!region_stack()->is_empty());
   175 }

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