1 /*
2 * Copyright (c) 2001, 2011, 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 */
24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
27
28 #include "gc_implementation/g1/concurrentMark.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30
31 // Counts the given memory region in the given task/worker
32 // counting data structures.
33 inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr,
34 size_t* marked_bytes_array,
35 BitMap* task_card_bm) {
36 G1CollectedHeap* g1h = _g1h;
37 HeapWord* start = mr.start();
38 HeapWord* last = mr.last();
39 size_t region_size = mr.byte_size();
40 size_t index = hr->hrs_index();
41
42 assert(!hr->continuesHumongous(), "should not be HC region");
43 assert(hr == g1h->heap_region_containing(start), "sanity");
44 assert(hr == g1h->heap_region_containing(mr.last()), "sanity");
45 assert(marked_bytes_array != NULL, "pre-condition");
46 assert(task_card_bm != NULL, "pre-condition");
47
48 // Add to the task local marked bytes for this region.
49 marked_bytes_array[index] += region_size;
50
51 // Below, the term "card num" means the result of shifting an address
52 // by the card shift -- address 0 corresponds to card number 0. One
53 // must subtract the card num of the bottom of the heap to obtain a
54 // card table index.
55
56 intptr_t start_card_num = intptr_t(uintptr_t(start) >> CardTableModRefBS::card_shift);
57 intptr_t last_card_num = intptr_t(uintptr_t(last) >> CardTableModRefBS::card_shift);
58
59 BitMap::idx_t start_idx = start_card_num - heap_bottom_card_num();
60 BitMap::idx_t last_idx = last_card_num - heap_bottom_card_num();
61
62 // The card bitmap is task/worker specific => no need to use 'par' routines.
63 // Set bits in the inclusive bit range [start_idx, last_idx].
64 for (BitMap::idx_t i = start_idx; i <= last_idx; i += 1) {
65 task_card_bm->set_bit(i);
66 }
67 }
68
69 // Counts the given memory region in the ask/worker counting
70 // data structures for the given worker id.
71 inline void ConcurrentMark::count_region(MemRegion mr, int worker_i) {
72 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_i);
73 BitMap* task_card_bm = count_card_bitmap_for(worker_i);
74 HeapWord* addr = mr.start();
75 HeapRegion* hr = _g1h->heap_region_containing(addr);
76 count_region(mr, hr, marked_bytes_array, task_card_bm);
77 }
78
79 // Counts the given object in the given task/worker counting data structures.
80 inline void ConcurrentMark::count_object(oop obj,
81 HeapRegion* hr,
82 size_t* marked_bytes_array,
83 BitMap* task_card_bm) {
84 MemRegion mr((HeapWord*)obj, obj->size());
85 count_region(mr, hr, marked_bytes_array, task_card_bm);
86 }
87
88 // Counts the given object in the task/worker counting data
89 // structures for the given worker id.
90 inline void ConcurrentMark::count_object(oop obj, HeapRegion* hr, int worker_i) {
91 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_i);
92 BitMap* task_card_bm = count_card_bitmap_for(worker_i);
93 HeapWord* addr = (HeapWord*) obj;
94 count_object(obj, hr, marked_bytes_array, task_card_bm);
95 }
96
97 // Attempts to mark the given object and, if successful, counts
98 // the object in the given task/worker counting structures.
99 inline bool ConcurrentMark::par_mark_and_count(oop obj,
100 HeapRegion* hr,
101 size_t* marked_bytes_array,
102 BitMap* task_card_bm) {
103 HeapWord* addr = (HeapWord*)obj;
104 if (_nextMarkBitMap->parMark(addr)) {
105 // Update the task specific count data for the object.
106 count_object(obj, hr, marked_bytes_array, task_card_bm);
107 return true;
108 }
109 return false;
110 }
111
112 // Attempts to mark the given object and, if successful, counts
113 // the object in the task/worker counting structures for the
114 // given worker id.
115 inline bool ConcurrentMark::par_mark_and_count(oop obj,
116 HeapRegion* hr,
117 int worker_i) {
118 HeapWord* addr = (HeapWord*)obj;
119 if (_nextMarkBitMap->parMark(addr)) {
120 // Update the task specific count data for the object.
121 count_object(obj, hr, worker_i);
122 return true;
123 }
124 return false;
125 }
126
127 // As above - but we don't know the heap region containing the
128 // object and so have to supply it.
129 inline bool ConcurrentMark::par_mark_and_count(oop obj, int worker_i) {
130 HeapWord* addr = (HeapWord*)obj;
131 HeapRegion* hr = _g1h->heap_region_containing(addr);
132 return par_mark_and_count(obj, hr, worker_i);
133 }
134
135 // Unconditionally mark the given object, and unconditinally count
136 // the object in the counting structures for worker id 0.
137 // Should *not* be called from parallel code.
138 inline bool ConcurrentMark::mark_and_count(oop obj, HeapRegion* hr) {
139 HeapWord* addr = (HeapWord*)obj;
140 _nextMarkBitMap->mark(addr);
141 // Update the task specific count data for the object.
142 count_object(obj, hr, 0 /* worker_i */);
143 return true;
144 }
145
146 // As above - but we don't have the heap region containing the
147 // object, so we have to supply it.
148 inline bool ConcurrentMark::mark_and_count(oop obj) {
149 HeapWord* addr = (HeapWord*)obj;
150 HeapRegion* hr = _g1h->heap_region_containing(addr);
151 return mark_and_count(obj, hr);
152 }
153
154 inline void CMTask::push(oop obj) {
155 HeapWord* objAddr = (HeapWord*) obj;
156 assert(_g1h->is_in_g1_reserved(objAddr), "invariant");
157 assert(!_g1h->is_on_master_free_list(
158 _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant");
159 assert(!_g1h->is_obj_ill(obj), "invariant");
160 assert(_nextMarkBitMap->isMarked(objAddr), "invariant");
161
162 if (_cm->verbose_high()) {
163 gclog_or_tty->print_cr("[%d] pushing "PTR_FORMAT, _task_id, (void*) obj);
164 }
165
166 if (!_task_queue->push(obj)) {
167 // The local task queue looks full. We need to push some entries
168 // to the global stack.
169
170 if (_cm->verbose_medium()) {
171 gclog_or_tty->print_cr("[%d] task queue overflow, "
172 "moving entries to the global stack",
173 _task_id);
174 }
175 move_entries_to_global_stack();
176
177 // this should succeed since, even if we overflow the global
178 // stack, we should have definitely removed some entries from the
179 // local queue. So, there must be space on it.
180 bool success = _task_queue->push(obj);
181 assert(success, "invariant");
182 }
183
184 statsOnly( int tmp_size = _task_queue->size();
185 if (tmp_size > _local_max_size) {
186 _local_max_size = tmp_size;
187 }
188 ++_local_pushes );
189 }
190
191 // This determines whether the method below will check both the local
192 // and global fingers when determining whether to push on the stack a
193 // gray object (value 1) or whether it will only check the global one
194 // (value 0). The tradeoffs are that the former will be a bit more
195 // accurate and possibly push less on the stack, but it might also be
196 // a little bit slower.
197
198 #define _CHECK_BOTH_FINGERS_ 1
199
200 inline void CMTask::deal_with_reference(oop obj) {
201 if (_cm->verbose_high()) {
202 gclog_or_tty->print_cr("[%d] we're dealing with reference = "PTR_FORMAT,
203 _task_id, (void*) obj);
204 }
205
206 ++_refs_reached;
207
208 HeapWord* objAddr = (HeapWord*) obj;
209 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error");
210 if (_g1h->is_in_g1_reserved(objAddr)) {
211 assert(obj != NULL, "null check is implicit");
212 if (!_nextMarkBitMap->isMarked(objAddr)) {
213 // Only get the containing region if the object is not marked on the
214 // bitmap (otherwise, it's a waste of time since we won't do
215 // anything with it).
216 HeapRegion* hr = _g1h->heap_region_containing_raw(obj);
217 if (!hr->obj_allocated_since_next_marking(obj)) {
218 if (_cm->verbose_high()) {
219 gclog_or_tty->print_cr("[%d] "PTR_FORMAT" is not considered marked",
220 _task_id, (void*) obj);
221 }
222
223 // we need to mark it first
224 if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) {
225 // No OrderAccess:store_load() is needed. It is implicit in the
226 // CAS done in CMBitMap::parMark() call in the routine above.
227 HeapWord* global_finger = _cm->finger();
228
229 #if _CHECK_BOTH_FINGERS_
230 // we will check both the local and global fingers
231
232 if (_finger != NULL && objAddr < _finger) {
233 if (_cm->verbose_high()) {
234 gclog_or_tty->print_cr("[%d] below the local finger ("PTR_FORMAT"), "
235 "pushing it", _task_id, _finger);
236 }
237 push(obj);
238 } else if (_curr_region != NULL && objAddr < _region_limit) {
239 // do nothing
240 } else if (objAddr < global_finger) {
241 // Notice that the global finger might be moving forward
242 // concurrently. This is not a problem. In the worst case, we
243 // mark the object while it is above the global finger and, by
244 // the time we read the global finger, it has moved forward
245 // passed this object. In this case, the object will probably
246 // be visited when a task is scanning the region and will also
247 // be pushed on the stack. So, some duplicate work, but no
248 // correctness problems.
249
250 if (_cm->verbose_high()) {
251 gclog_or_tty->print_cr("[%d] below the global finger "
252 "("PTR_FORMAT"), pushing it",
253 _task_id, global_finger);
254 }
255 push(obj);
256 } else {
257 // do nothing
258 }
259 #else // _CHECK_BOTH_FINGERS_
260 // we will only check the global finger
261
262 if (objAddr < global_finger) {
263 // see long comment above
264
265 if (_cm->verbose_high()) {
266 gclog_or_tty->print_cr("[%d] below the global finger "
267 "("PTR_FORMAT"), pushing it",
268 _task_id, global_finger);
269 }
270 push(obj);
271 }
272 #endif // _CHECK_BOTH_FINGERS_
273 }
274 }
275 }
276 }
277 }
278
279 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP