1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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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).
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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 // Returns the index in the liveness accounting card bitmap
32 // for the given address
33 inline BitMap::idx_t ConcurrentMark::card_bitmap_index_for(HeapWord* addr) {
34 // Below, the term "card num" means the result of shifting an address
35 // by the card shift -- address 0 corresponds to card number 0. One
36 // must subtract the card num of the bottom of the heap to obtain a
37 // card table index.
38
39 intptr_t card_num = intptr_t(uintptr_t(addr) >> CardTableModRefBS::card_shift);
40 return card_num - heap_bottom_card_num();
41 }
42
43 // Counts the given memory region in the given task/worker
44 // counting data structures.
45 inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr,
46 size_t* marked_bytes_array,
47 BitMap* task_card_bm) {
48 G1CollectedHeap* g1h = _g1h;
49 HeapWord* start = mr.start();
50 HeapWord* last = mr.last();
51 size_t region_size_bytes = mr.byte_size();
52 uint index = hr->hrs_index();
53
54 assert(!hr->continuesHumongous(), "should not be HC region");
55 assert(hr == g1h->heap_region_containing(start), "sanity");
56 assert(hr == g1h->heap_region_containing(mr.last()), "sanity");
57 assert(marked_bytes_array != NULL, "pre-condition");
58 assert(task_card_bm != NULL, "pre-condition");
59
60 // Add to the task local marked bytes for this region.
61 marked_bytes_array[index] += region_size_bytes;
62
63 BitMap::idx_t start_idx = card_bitmap_index_for(start);
64 BitMap::idx_t last_idx = card_bitmap_index_for(last);
65
66 // The card bitmap is task/worker specific => no need to use 'par' routines.
67 // Set bits in the inclusive bit range [start_idx, last_idx].
68 //
69 // For small ranges use a simple loop; otherwise use set_range
70 // The range are the cards that are spanned by the object/region
71 // so 8 cards will allow objects/regions up to 4K to be handled
72 // using the loop.
73 if ((last_idx - start_idx) <= 8) {
74 for (BitMap::idx_t i = start_idx; i <= last_idx; i += 1) {
75 task_card_bm->set_bit(i);
76 }
77 } else {
78 assert(last_idx < task_card_bm->size(), "sanity");
79 // Note: BitMap::set_range() is exclusive.
80 task_card_bm->set_range(start_idx, last_idx+1);
81 }
82 }
83
84 // Counts the given memory region in the task/worker counting
85 // data structures for the given worker id.
86 inline void ConcurrentMark::count_region(MemRegion mr,
87 HeapRegion* hr,
88 uint worker_id) {
89 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id);
90 BitMap* task_card_bm = count_card_bitmap_for(worker_id);
91 count_region(mr, hr, marked_bytes_array, task_card_bm);
92 }
93
94 // Counts the given memory region, which may be a single object, in the
95 // task/worker counting data structures for the given worker id.
96 inline void ConcurrentMark::count_region(MemRegion mr, uint worker_id) {
97 HeapWord* addr = mr.start();
98 HeapRegion* hr = _g1h->heap_region_containing_raw(addr);
99 count_region(mr, hr, worker_id);
100 }
101
102 // Counts the given object in the given task/worker counting data structures.
103 inline void ConcurrentMark::count_object(oop obj,
104 HeapRegion* hr,
105 size_t* marked_bytes_array,
106 BitMap* task_card_bm) {
107 MemRegion mr((HeapWord*)obj, obj->size());
108 count_region(mr, hr, marked_bytes_array, task_card_bm);
109 }
110
111 // Counts the given object in the task/worker counting data
112 // structures for the given worker id.
113 inline void ConcurrentMark::count_object(oop obj,
114 HeapRegion* hr,
115 uint worker_id) {
116 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id);
117 BitMap* task_card_bm = count_card_bitmap_for(worker_id);
118 HeapWord* addr = (HeapWord*) obj;
119 count_object(obj, hr, marked_bytes_array, task_card_bm);
120 }
121
122 // Attempts to mark the given object and, if successful, counts
123 // the object in the given task/worker counting structures.
124 inline bool ConcurrentMark::par_mark_and_count(oop obj,
125 HeapRegion* hr,
126 size_t* marked_bytes_array,
127 BitMap* task_card_bm) {
128 HeapWord* addr = (HeapWord*)obj;
129 if (_nextMarkBitMap->parMark(addr)) {
130 // Update the task specific count data for the object.
131 count_object(obj, hr, marked_bytes_array, task_card_bm);
132 return true;
133 }
134 return false;
135 }
136
137 // Attempts to mark the given object and, if successful, counts
138 // the object in the task/worker counting structures for the
139 // given worker id.
140 inline bool ConcurrentMark::par_mark_and_count(oop obj,
141 size_t word_size,
142 HeapRegion* hr,
143 uint worker_id) {
144 HeapWord* addr = (HeapWord*)obj;
145 if (_nextMarkBitMap->parMark(addr)) {
146 MemRegion mr(addr, word_size);
147 count_region(mr, hr, worker_id);
148 return true;
149 }
150 return false;
151 }
152
153 // Attempts to mark the given object and, if successful, counts
154 // the object in the task/worker counting structures for the
155 // given worker id.
156 inline bool ConcurrentMark::par_mark_and_count(oop obj,
157 HeapRegion* hr,
158 uint worker_id) {
159 HeapWord* addr = (HeapWord*)obj;
160 if (_nextMarkBitMap->parMark(addr)) {
161 // Update the task specific count data for the object.
162 count_object(obj, hr, worker_id);
163 return true;
164 }
165 return false;
166 }
167
168 // As above - but we don't know the heap region containing the
169 // object and so have to supply it.
170 inline bool ConcurrentMark::par_mark_and_count(oop obj, uint worker_id) {
171 HeapWord* addr = (HeapWord*)obj;
172 HeapRegion* hr = _g1h->heap_region_containing_raw(addr);
173 return par_mark_and_count(obj, hr, worker_id);
174 }
175
176 // Similar to the above routine but we already know the size, in words, of
177 // the object that we wish to mark/count
178 inline bool ConcurrentMark::par_mark_and_count(oop obj,
179 size_t word_size,
180 uint worker_id) {
181 HeapWord* addr = (HeapWord*)obj;
182 if (_nextMarkBitMap->parMark(addr)) {
183 // Update the task specific count data for the object.
184 MemRegion mr(addr, word_size);
185 count_region(mr, worker_id);
186 return true;
187 }
188 return false;
189 }
190
191 // Unconditionally mark the given object, and unconditinally count
192 // the object in the counting structures for worker id 0.
193 // Should *not* be called from parallel code.
194 inline bool ConcurrentMark::mark_and_count(oop obj, HeapRegion* hr) {
195 HeapWord* addr = (HeapWord*)obj;
196 _nextMarkBitMap->mark(addr);
197 // Update the task specific count data for the object.
198 count_object(obj, hr, 0 /* worker_id */);
199 return true;
200 }
201
202 // As above - but we don't have the heap region containing the
203 // object, so we have to supply it.
204 inline bool ConcurrentMark::mark_and_count(oop obj) {
205 HeapWord* addr = (HeapWord*)obj;
206 HeapRegion* hr = _g1h->heap_region_containing_raw(addr);
207 return mark_and_count(obj, hr);
208 }
209
210 inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) {
211 HeapWord* start_addr = MAX2(startWord(), mr.start());
212 HeapWord* end_addr = MIN2(endWord(), mr.end());
213
214 if (end_addr > start_addr) {
215 // Right-open interval [start-offset, end-offset).
216 BitMap::idx_t start_offset = heapWordToOffset(start_addr);
217 BitMap::idx_t end_offset = heapWordToOffset(end_addr);
218
219 start_offset = _bm.get_next_one_offset(start_offset, end_offset);
220 while (start_offset < end_offset) {
221 HeapWord* obj_addr = offsetToHeapWord(start_offset);
222 oop obj = (oop) obj_addr;
223 if (!cl->do_bit(start_offset)) {
224 return false;
225 }
226 HeapWord* next_addr = MIN2(obj_addr + obj->size(), end_addr);
227 BitMap::idx_t next_offset = heapWordToOffset(next_addr);
228 start_offset = _bm.get_next_one_offset(next_offset, end_offset);
229 }
230 }
231 return true;
232 }
233
234 inline bool CMBitMapRO::iterate(BitMapClosure* cl) {
235 MemRegion mr(startWord(), sizeInWords());
236 return iterate(cl, mr);
237 }
238
239 inline void CMTask::push(oop obj) {
240 HeapWord* objAddr = (HeapWord*) obj;
241 assert(_g1h->is_in_g1_reserved(objAddr), "invariant");
242 assert(!_g1h->is_on_master_free_list(
243 _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant");
244 assert(!_g1h->is_obj_ill(obj), "invariant");
245 assert(_nextMarkBitMap->isMarked(objAddr), "invariant");
246
247 if (_cm->verbose_high()) {
248 gclog_or_tty->print_cr("[%d] pushing "PTR_FORMAT, _task_id, (void*) obj);
249 }
250
251 if (!_task_queue->push(obj)) {
252 // The local task queue looks full. We need to push some entries
253 // to the global stack.
254
255 if (_cm->verbose_medium()) {
256 gclog_or_tty->print_cr("[%d] task queue overflow, "
257 "moving entries to the global stack",
258 _task_id);
259 }
260 move_entries_to_global_stack();
261
262 // this should succeed since, even if we overflow the global
263 // stack, we should have definitely removed some entries from the
264 // local queue. So, there must be space on it.
265 bool success = _task_queue->push(obj);
266 assert(success, "invariant");
267 }
268
269 statsOnly( int tmp_size = _task_queue->size();
270 if (tmp_size > _local_max_size) {
271 _local_max_size = tmp_size;
272 }
273 ++_local_pushes );
274 }
275
276 // This determines whether the method below will check both the local
277 // and global fingers when determining whether to push on the stack a
278 // gray object (value 1) or whether it will only check the global one
279 // (value 0). The tradeoffs are that the former will be a bit more
280 // accurate and possibly push less on the stack, but it might also be
281 // a little bit slower.
282
283 #define _CHECK_BOTH_FINGERS_ 1
284
285 inline void CMTask::deal_with_reference(oop obj) {
286 if (_cm->verbose_high()) {
287 gclog_or_tty->print_cr("[%d] we're dealing with reference = "PTR_FORMAT,
288 _task_id, (void*) obj);
289 }
290
291 ++_refs_reached;
292
293 HeapWord* objAddr = (HeapWord*) obj;
294 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error");
295 if (_g1h->is_in_g1_reserved(objAddr)) {
296 assert(obj != NULL, "null check is implicit");
297 if (!_nextMarkBitMap->isMarked(objAddr)) {
298 // Only get the containing region if the object is not marked on the
299 // bitmap (otherwise, it's a waste of time since we won't do
300 // anything with it).
301 HeapRegion* hr = _g1h->heap_region_containing_raw(obj);
302 if (!hr->obj_allocated_since_next_marking(obj)) {
303 if (_cm->verbose_high()) {
304 gclog_or_tty->print_cr("[%d] "PTR_FORMAT" is not considered marked",
305 _task_id, (void*) obj);
306 }
307
308 // we need to mark it first
309 if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) {
310 // No OrderAccess:store_load() is needed. It is implicit in the
311 // CAS done in CMBitMap::parMark() call in the routine above.
312 HeapWord* global_finger = _cm->finger();
313
314 #if _CHECK_BOTH_FINGERS_
315 // we will check both the local and global fingers
316
317 if (_finger != NULL && objAddr < _finger) {
318 if (_cm->verbose_high()) {
319 gclog_or_tty->print_cr("[%d] below the local finger ("PTR_FORMAT"), "
320 "pushing it", _task_id, _finger);
321 }
322 push(obj);
323 } else if (_curr_region != NULL && objAddr < _region_limit) {
324 // do nothing
325 } else if (objAddr < global_finger) {
326 // Notice that the global finger might be moving forward
327 // concurrently. This is not a problem. In the worst case, we
328 // mark the object while it is above the global finger and, by
329 // the time we read the global finger, it has moved forward
330 // passed this object. In this case, the object will probably
331 // be visited when a task is scanning the region and will also
332 // be pushed on the stack. So, some duplicate work, but no
333 // correctness problems.
334
335 if (_cm->verbose_high()) {
336 gclog_or_tty->print_cr("[%d] below the global finger "
337 "("PTR_FORMAT"), pushing it",
338 _task_id, global_finger);
339 }
340 push(obj);
341 } else {
342 // do nothing
343 }
344 #else // _CHECK_BOTH_FINGERS_
345 // we will only check the global finger
346
347 if (objAddr < global_finger) {
348 // see long comment above
349
350 if (_cm->verbose_high()) {
351 gclog_or_tty->print_cr("[%d] below the global finger "
352 "("PTR_FORMAT"), pushing it",
353 _task_id, global_finger);
354 }
355 push(obj);
356 }
357 #endif // _CHECK_BOTH_FINGERS_
358 }
359 }
360 }
361 }
362 }
363
364 inline void ConcurrentMark::markPrev(oop p) {
365 assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity");
366 // Note we are overriding the read-only view of the prev map here, via
367 // the cast.
368 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p);
369 }
370
371 inline void ConcurrentMark::grayRoot(oop obj, size_t word_size,
372 uint worker_id, HeapRegion* hr) {
373 assert(obj != NULL, "pre-condition");
374 HeapWord* addr = (HeapWord*) obj;
375 if (hr == NULL) {
376 hr = _g1h->heap_region_containing_raw(addr);
377 } else {
378 assert(hr->is_in(addr), "pre-condition");
379 }
380 assert(hr != NULL, "sanity");
381 // Given that we're looking for a region that contains an object
382 // header it's impossible to get back a HC region.
383 assert(!hr->continuesHumongous(), "sanity");
384
385 // We cannot assert that word_size == obj->size() given that obj
386 // might not be in a consistent state (another thread might be in
387 // the process of copying it). So the best thing we can do is to
388 // assert that word_size is under an upper bound which is its
389 // containing region's capacity.
390 assert(word_size * HeapWordSize <= hr->capacity(),
391 err_msg("size: "SIZE_FORMAT" capacity: "SIZE_FORMAT" "HR_FORMAT,
392 word_size * HeapWordSize, hr->capacity(),
393 HR_FORMAT_PARAMS(hr)));
394
395 if (addr < hr->next_top_at_mark_start()) {
396 if (!_nextMarkBitMap->isMarked(addr)) {
397 par_mark_and_count(obj, word_size, hr, worker_id);
398 }
399 }
400 }
401
402 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP