Mon, 03 Aug 2009 12:59:30 -0700
6865703: G1: Parallelize hot card cache cleanup
Summary: Have the GC worker threads clear the hot card cache in parallel by having each worker thread claim a chunk of the card cache and process the cards in that chunk. The size of the chunks that each thread will claim is determined at VM initialization from the size of the card cache and the number of worker threads.
Reviewed-by: jmasa, tonyp
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 # include "incls/_precompiled.incl"
26 # include "incls/_satbQueue.cpp.incl"
28 void ObjPtrQueue::apply_closure(ObjectClosure* cl) {
29 if (_buf != NULL) {
30 apply_closure_to_buffer(cl, _buf, _index, _sz);
31 _index = _sz;
32 }
33 }
35 void ObjPtrQueue::apply_closure_to_buffer(ObjectClosure* cl,
36 void** buf, size_t index, size_t sz) {
37 if (cl == NULL) return;
38 for (size_t i = index; i < sz; i += oopSize) {
39 oop obj = (oop)buf[byte_index_to_index((int)i)];
40 // There can be NULL entries because of destructors.
41 if (obj != NULL) {
42 cl->do_object(obj);
43 }
44 }
45 }
47 #ifdef ASSERT
48 void ObjPtrQueue::verify_oops_in_buffer() {
49 if (_buf == NULL) return;
50 for (size_t i = _index; i < _sz; i += oopSize) {
51 oop obj = (oop)_buf[byte_index_to_index((int)i)];
52 assert(obj != NULL && obj->is_oop(true /* ignore mark word */),
53 "Not an oop");
54 }
55 }
56 #endif
58 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
59 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
60 #endif // _MSC_VER
63 SATBMarkQueueSet::SATBMarkQueueSet() :
64 PtrQueueSet(),
65 _closure(NULL), _par_closures(NULL),
66 _shared_satb_queue(this, true /*perm*/)
67 {}
69 void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
70 int max_completed_queue,
71 Mutex* lock) {
72 PtrQueueSet::initialize(cbl_mon, fl_lock, max_completed_queue);
73 _shared_satb_queue.set_lock(lock);
74 if (ParallelGCThreads > 0) {
75 _par_closures = NEW_C_HEAP_ARRAY(ObjectClosure*, ParallelGCThreads);
76 }
77 }
80 void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) {
81 DEBUG_ONLY(t->satb_mark_queue().verify_oops_in_buffer();)
82 t->satb_mark_queue().handle_zero_index();
83 }
85 void SATBMarkQueueSet::set_active_all_threads(bool b) {
86 _all_active = b;
87 for(JavaThread* t = Threads::first(); t; t = t->next()) {
88 t->satb_mark_queue().set_active(b);
89 }
90 }
92 void SATBMarkQueueSet::set_closure(ObjectClosure* closure) {
93 _closure = closure;
94 }
96 void SATBMarkQueueSet::set_par_closure(int i, ObjectClosure* par_closure) {
97 assert(ParallelGCThreads > 0 && _par_closures != NULL, "Precondition");
98 _par_closures[i] = par_closure;
99 }
101 void SATBMarkQueueSet::iterate_closure_all_threads() {
102 for(JavaThread* t = Threads::first(); t; t = t->next()) {
103 t->satb_mark_queue().apply_closure(_closure);
104 }
105 shared_satb_queue()->apply_closure(_closure);
106 }
108 void SATBMarkQueueSet::par_iterate_closure_all_threads(int worker) {
109 SharedHeap* sh = SharedHeap::heap();
110 int parity = sh->strong_roots_parity();
112 for(JavaThread* t = Threads::first(); t; t = t->next()) {
113 if (t->claim_oops_do(true, parity)) {
114 t->satb_mark_queue().apply_closure(_par_closures[worker]);
115 }
116 }
117 // We'll have worker 0 do this one.
118 if (worker == 0) {
119 shared_satb_queue()->apply_closure(_par_closures[0]);
120 }
121 }
123 bool SATBMarkQueueSet::apply_closure_to_completed_buffer_work(bool par,
124 int worker) {
125 CompletedBufferNode* nd = NULL;
126 {
127 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
128 if (_completed_buffers_head != NULL) {
129 nd = _completed_buffers_head;
130 _completed_buffers_head = nd->next;
131 if (_completed_buffers_head == NULL) _completed_buffers_tail = NULL;
132 _n_completed_buffers--;
133 if (_n_completed_buffers == 0) _process_completed = false;
134 }
135 }
136 ObjectClosure* cl = (par ? _par_closures[worker] : _closure);
137 if (nd != NULL) {
138 ObjPtrQueue::apply_closure_to_buffer(cl, nd->buf, 0, _sz);
139 deallocate_buffer(nd->buf);
140 delete nd;
141 return true;
142 } else {
143 return false;
144 }
145 }
147 void SATBMarkQueueSet::abandon_partial_marking() {
148 CompletedBufferNode* buffers_to_delete = NULL;
149 {
150 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
151 while (_completed_buffers_head != NULL) {
152 CompletedBufferNode* nd = _completed_buffers_head;
153 _completed_buffers_head = nd->next;
154 nd->next = buffers_to_delete;
155 buffers_to_delete = nd;
156 }
157 _completed_buffers_tail = NULL;
158 _n_completed_buffers = 0;
159 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
160 }
161 while (buffers_to_delete != NULL) {
162 CompletedBufferNode* nd = buffers_to_delete;
163 buffers_to_delete = nd->next;
164 deallocate_buffer(nd->buf);
165 delete nd;
166 }
167 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
168 // So we can safely manipulate these queues.
169 for (JavaThread* t = Threads::first(); t; t = t->next()) {
170 t->satb_mark_queue().reset();
171 }
172 shared_satb_queue()->reset();
173 }