Tue, 26 Jan 2010 16:52:29 -0800
6920090: G1: Disable ReduceInitialCardMarks at least until 6920109 is fixed
Summary: G1 now answers "no" to the query can_elide_initializing_store_barrier() in the product build. A debug flag allows alternate behaviour in debug builds.
Reviewed-by: iveresov, tonyp
1 /*
2 * Copyright 2001-2009 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 // There are various techniques that require threads to be able to log
26 // addresses. For example, a generational write barrier might log
27 // the addresses of modified old-generation objects. This type supports
28 // this operation.
30 // The definition of placement operator new(size_t, void*) in the <new>.
31 #include <new>
33 class PtrQueueSet;
34 class PtrQueue VALUE_OBJ_CLASS_SPEC {
36 protected:
37 // The ptr queue set to which this queue belongs.
38 PtrQueueSet* _qset;
40 // Whether updates should be logged.
41 bool _active;
43 // The buffer.
44 void** _buf;
45 // The index at which an object was last enqueued. Starts at "_sz"
46 // (indicating an empty buffer) and goes towards zero.
47 size_t _index;
49 // The size of the buffer.
50 size_t _sz;
52 // If true, the queue is permanent, and doesn't need to deallocate
53 // its buffer in the destructor (since that obtains a lock which may not
54 // be legally locked by then.
55 bool _perm;
57 // If there is a lock associated with this buffer, this is that lock.
58 Mutex* _lock;
60 PtrQueueSet* qset() { return _qset; }
62 public:
63 // Initialize this queue to contain a null buffer, and be part of the
64 // given PtrQueueSet.
65 PtrQueue(PtrQueueSet*, bool perm = false);
66 // Release any contained resources.
67 void flush();
68 // Calls flush() when destroyed.
69 ~PtrQueue() { flush(); }
71 // Associate a lock with a ptr queue.
72 void set_lock(Mutex* lock) { _lock = lock; }
74 void reset() { if (_buf != NULL) _index = _sz; }
76 // Enqueues the given "obj".
77 void enqueue(void* ptr) {
78 if (!_active) return;
79 else enqueue_known_active(ptr);
80 }
82 void handle_zero_index();
83 void locking_enqueue_completed_buffer(void** buf);
85 void enqueue_known_active(void* ptr);
87 size_t size() {
88 assert(_sz >= _index, "Invariant.");
89 return _buf == NULL ? 0 : _sz - _index;
90 }
92 // Set the "active" property of the queue to "b". An enqueue to an
93 // inactive thread is a no-op. Setting a queue to inactive resets its
94 // log to the empty state.
95 void set_active(bool b) {
96 _active = b;
97 if (!b && _buf != NULL) {
98 _index = _sz;
99 } else if (b && _buf != NULL) {
100 assert(_index == _sz, "invariant: queues are empty when activated.");
101 }
102 }
104 static int byte_index_to_index(int ind) {
105 assert((ind % oopSize) == 0, "Invariant.");
106 return ind / oopSize;
107 }
109 static int index_to_byte_index(int byte_ind) {
110 return byte_ind * oopSize;
111 }
113 // To support compiler.
114 static ByteSize byte_offset_of_index() {
115 return byte_offset_of(PtrQueue, _index);
116 }
117 static ByteSize byte_width_of_index() { return in_ByteSize(sizeof(size_t)); }
119 static ByteSize byte_offset_of_buf() {
120 return byte_offset_of(PtrQueue, _buf);
121 }
122 static ByteSize byte_width_of_buf() { return in_ByteSize(sizeof(void*)); }
124 static ByteSize byte_offset_of_active() {
125 return byte_offset_of(PtrQueue, _active);
126 }
127 static ByteSize byte_width_of_active() { return in_ByteSize(sizeof(bool)); }
129 };
131 class BufferNode {
132 size_t _index;
133 BufferNode* _next;
134 public:
135 BufferNode() : _index(0), _next(NULL) { }
136 BufferNode* next() const { return _next; }
137 void set_next(BufferNode* n) { _next = n; }
138 size_t index() const { return _index; }
139 void set_index(size_t i) { _index = i; }
141 // Align the size of the structure to the size of the pointer
142 static size_t aligned_size() {
143 static const size_t alignment = round_to(sizeof(BufferNode), sizeof(void*));
144 return alignment;
145 }
147 // BufferNode is allocated before the buffer.
148 // The chunk of memory that holds both of them is a block.
150 // Produce a new BufferNode given a buffer.
151 static BufferNode* new_from_buffer(void** buf) {
152 return new (make_block_from_buffer(buf)) BufferNode;
153 }
155 // The following are the required conversion routines:
156 static BufferNode* make_node_from_buffer(void** buf) {
157 return (BufferNode*)make_block_from_buffer(buf);
158 }
159 static void** make_buffer_from_node(BufferNode *node) {
160 return make_buffer_from_block(node);
161 }
162 static void* make_block_from_node(BufferNode *node) {
163 return (void*)node;
164 }
165 static void** make_buffer_from_block(void* p) {
166 return (void**)((char*)p + aligned_size());
167 }
168 static void* make_block_from_buffer(void** p) {
169 return (void*)((char*)p - aligned_size());
170 }
171 };
173 // A PtrQueueSet represents resources common to a set of pointer queues.
174 // In particular, the individual queues allocate buffers from this shared
175 // set, and return completed buffers to the set.
176 // All these variables are are protected by the TLOQ_CBL_mon. XXX ???
177 class PtrQueueSet VALUE_OBJ_CLASS_SPEC {
178 protected:
179 Monitor* _cbl_mon; // Protects the fields below.
180 BufferNode* _completed_buffers_head;
181 BufferNode* _completed_buffers_tail;
182 int _n_completed_buffers;
183 int _process_completed_threshold;
184 volatile bool _process_completed;
186 // This (and the interpretation of the first element as a "next"
187 // pointer) are protected by the TLOQ_FL_lock.
188 Mutex* _fl_lock;
189 BufferNode* _buf_free_list;
190 size_t _buf_free_list_sz;
191 // Queue set can share a freelist. The _fl_owner variable
192 // specifies the owner. It is set to "this" by default.
193 PtrQueueSet* _fl_owner;
195 // The size of all buffers in the set.
196 size_t _sz;
198 bool _all_active;
200 // If true, notify_all on _cbl_mon when the threshold is reached.
201 bool _notify_when_complete;
203 // Maximum number of elements allowed on completed queue: after that,
204 // enqueuer does the work itself. Zero indicates no maximum.
205 int _max_completed_queue;
206 int _completed_queue_padding;
208 int completed_buffers_list_length();
209 void assert_completed_buffer_list_len_correct_locked();
210 void assert_completed_buffer_list_len_correct();
212 protected:
213 // A mutator thread does the the work of processing a buffer.
214 // Returns "true" iff the work is complete (and the buffer may be
215 // deallocated).
216 virtual bool mut_process_buffer(void** buf) {
217 ShouldNotReachHere();
218 return false;
219 }
221 public:
222 // Create an empty ptr queue set.
223 PtrQueueSet(bool notify_when_complete = false);
225 // Because of init-order concerns, we can't pass these as constructor
226 // arguments.
227 void initialize(Monitor* cbl_mon, Mutex* fl_lock,
228 int process_completed_threshold,
229 int max_completed_queue,
230 PtrQueueSet *fl_owner = NULL) {
231 _max_completed_queue = max_completed_queue;
232 _process_completed_threshold = process_completed_threshold;
233 _completed_queue_padding = 0;
234 assert(cbl_mon != NULL && fl_lock != NULL, "Init order issue?");
235 _cbl_mon = cbl_mon;
236 _fl_lock = fl_lock;
237 _fl_owner = (fl_owner != NULL) ? fl_owner : this;
238 }
240 // Return an empty oop array of size _sz (required to be non-zero).
241 void** allocate_buffer();
243 // Return an empty buffer to the free list. The "buf" argument is
244 // required to be a pointer to the head of an array of length "_sz".
245 void deallocate_buffer(void** buf);
247 // Declares that "buf" is a complete buffer.
248 void enqueue_complete_buffer(void** buf, size_t index = 0);
250 // To be invoked by the mutator.
251 bool process_or_enqueue_complete_buffer(void** buf);
253 bool completed_buffers_exist_dirty() {
254 return _n_completed_buffers > 0;
255 }
257 bool process_completed_buffers() { return _process_completed; }
258 void set_process_completed(bool x) { _process_completed = x; }
260 bool active() { return _all_active; }
262 // Set the buffer size. Should be called before any "enqueue" operation
263 // can be called. And should only be called once.
264 void set_buffer_size(size_t sz);
266 // Get the buffer size.
267 size_t buffer_size() { return _sz; }
269 // Get/Set the number of completed buffers that triggers log processing.
270 void set_process_completed_threshold(int sz) { _process_completed_threshold = sz; }
271 int process_completed_threshold() const { return _process_completed_threshold; }
273 // Must only be called at a safe point. Indicates that the buffer free
274 // list size may be reduced, if that is deemed desirable.
275 void reduce_free_list();
277 int completed_buffers_num() { return _n_completed_buffers; }
279 void merge_bufferlists(PtrQueueSet* src);
281 void set_max_completed_queue(int m) { _max_completed_queue = m; }
282 int max_completed_queue() { return _max_completed_queue; }
284 void set_completed_queue_padding(int padding) { _completed_queue_padding = padding; }
285 int completed_queue_padding() { return _completed_queue_padding; }
287 // Notify the consumer if the number of buffers crossed the threshold
288 void notify_if_necessary();
289 };