1 /*
2 * Copyright (c) 2000, 2015, 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 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/cardTableModRefBS.inline.hpp"
28 #include "memory/cardTableRS.hpp"
29 #include "memory/sharedHeap.hpp"
30 #include "memory/space.hpp"
31 #include "memory/space.inline.hpp"
32 #include "memory/universe.hpp"
33 #include "runtime/java.hpp"
34 #include "runtime/mutexLocker.hpp"
35 #include "runtime/virtualspace.hpp"
36 #include "services/memTracker.hpp"
37 #include "utilities/macros.hpp"
38 #ifdef COMPILER1
39 #include "c1/c1_LIR.hpp"
40 #include "c1/c1_LIRGenerator.hpp"
41 #endif
42
43 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
44 // enumerate ref fields that have been modified (since the last
45 // enumeration.)
46
47 size_t CardTableModRefBS::compute_byte_map_size()
48 {
49 assert(_guard_index == cards_required(_whole_heap.word_size()) - 1,
50 "uninitialized, check declaration order");
51 assert(_page_size != 0, "uninitialized, check declaration order");
52 const size_t granularity = os::vm_allocation_granularity();
53 return align_size_up(_guard_index + 1, MAX2(_page_size, granularity));
54 }
55
56 CardTableModRefBS::CardTableModRefBS(MemRegion whole_heap, BarrierSet::Name kind) :
57 ModRefBarrierSet(kind),
58 _whole_heap(whole_heap),
59 _guard_index(0),
60 _guard_region(),
61 _last_valid_index(0),
62 _page_size(os::vm_page_size()),
63 _byte_map_size(0),
64 _covered(NULL),
65 _committed(NULL),
66 _cur_covered_regions(0),
67 _byte_map(NULL),
68 byte_map_base(NULL),
69 // LNC functionality
70 _lowest_non_clean(NULL),
71 _lowest_non_clean_chunk_size(NULL),
72 _lowest_non_clean_base_chunk_index(NULL),
73 _last_LNC_resizing_collection(NULL)
74 {
75 assert((uintptr_t(_whole_heap.start()) & (card_size - 1)) == 0, "heap must start at card boundary");
76 assert((uintptr_t(_whole_heap.end()) & (card_size - 1)) == 0, "heap must end at card boundary");
77
78 assert(card_size <= 512, "card_size must be less than 512"); // why?
79
80 _covered = new MemRegion[_max_covered_regions];
81 if (_covered == NULL) {
82 vm_exit_during_initialization("Could not allocate card table covered region set.");
83 }
84 }
85
86 void CardTableModRefBS::initialize() {
87 _guard_index = cards_required(_whole_heap.word_size()) - 1;
88 _last_valid_index = _guard_index - 1;
89
90 _byte_map_size = compute_byte_map_size();
91
92 HeapWord* low_bound = _whole_heap.start();
93 HeapWord* high_bound = _whole_heap.end();
94
95 _cur_covered_regions = 0;
96 _committed = new MemRegion[_max_covered_regions];
97 if (_committed == NULL) {
98 vm_exit_during_initialization("Could not allocate card table committed region set.");
99 }
100
101 const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 :
102 MAX2(_page_size, (size_t) os::vm_allocation_granularity());
103 ReservedSpace heap_rs(_byte_map_size, rs_align, false);
104
105 MemTracker::record_virtual_memory_type((address)heap_rs.base(), mtGC);
106
107 os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1,
108 _page_size, heap_rs.base(), heap_rs.size());
109 if (!heap_rs.is_reserved()) {
110 vm_exit_during_initialization("Could not reserve enough space for the "
111 "card marking array");
112 }
113
114 // The assembler store_check code will do an unsigned shift of the oop,
115 // then add it to byte_map_base, i.e.
116 //
117 // _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift)
118 _byte_map = (jbyte*) heap_rs.base();
119 byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
120 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
121 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
122
123 jbyte* guard_card = &_byte_map[_guard_index];
124 uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size);
125 _guard_region = MemRegion((HeapWord*)guard_page, _page_size);
126 os::commit_memory_or_exit((char*)guard_page, _page_size, _page_size,
127 !ExecMem, "card table last card");
128 *guard_card = last_card;
129
130 _lowest_non_clean =
131 NEW_C_HEAP_ARRAY(CardArr, _max_covered_regions, mtGC);
132 _lowest_non_clean_chunk_size =
133 NEW_C_HEAP_ARRAY(size_t, _max_covered_regions, mtGC);
134 _lowest_non_clean_base_chunk_index =
135 NEW_C_HEAP_ARRAY(uintptr_t, _max_covered_regions, mtGC);
136 _last_LNC_resizing_collection =
137 NEW_C_HEAP_ARRAY(int, _max_covered_regions, mtGC);
138 if (_lowest_non_clean == NULL
139 || _lowest_non_clean_chunk_size == NULL
140 || _lowest_non_clean_base_chunk_index == NULL
141 || _last_LNC_resizing_collection == NULL)
142 vm_exit_during_initialization("couldn't allocate an LNC array.");
143 for (int i = 0; i < _max_covered_regions; i++) {
144 _lowest_non_clean[i] = NULL;
145 _lowest_non_clean_chunk_size[i] = 0;
146 _last_LNC_resizing_collection[i] = -1;
147 }
148
149 if (TraceCardTableModRefBS) {
150 gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: ");
151 gclog_or_tty->print_cr(" "
152 " &_byte_map[0]: " INTPTR_FORMAT
153 " &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
154 p2i(&_byte_map[0]),
155 p2i(&_byte_map[_last_valid_index]));
156 gclog_or_tty->print_cr(" "
157 " byte_map_base: " INTPTR_FORMAT,
158 p2i(byte_map_base));
159 }
160 }
161
162 CardTableModRefBS::~CardTableModRefBS() {
163 if (_covered) {
164 delete[] _covered;
165 _covered = NULL;
166 }
167 if (_committed) {
168 delete[] _committed;
169 _committed = NULL;
170 }
171 if (_lowest_non_clean) {
172 FREE_C_HEAP_ARRAY(CardArr, _lowest_non_clean);
173 _lowest_non_clean = NULL;
174 }
175 if (_lowest_non_clean_chunk_size) {
176 FREE_C_HEAP_ARRAY(size_t, _lowest_non_clean_chunk_size);
177 _lowest_non_clean_chunk_size = NULL;
178 }
179 if (_lowest_non_clean_base_chunk_index) {
180 FREE_C_HEAP_ARRAY(uintptr_t, _lowest_non_clean_base_chunk_index);
181 _lowest_non_clean_base_chunk_index = NULL;
182 }
183 if (_last_LNC_resizing_collection) {
184 FREE_C_HEAP_ARRAY(int, _last_LNC_resizing_collection);
185 _last_LNC_resizing_collection = NULL;
186 }
187 }
188
189 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) {
190 int i;
191 for (i = 0; i < _cur_covered_regions; i++) {
192 if (_covered[i].start() == base) return i;
193 if (_covered[i].start() > base) break;
194 }
195 // If we didn't find it, create a new one.
196 assert(_cur_covered_regions < _max_covered_regions,
197 "too many covered regions");
198 // Move the ones above up, to maintain sorted order.
199 for (int j = _cur_covered_regions; j > i; j--) {
200 _covered[j] = _covered[j-1];
201 _committed[j] = _committed[j-1];
202 }
203 int res = i;
204 _cur_covered_regions++;
205 _covered[res].set_start(base);
206 _covered[res].set_word_size(0);
207 jbyte* ct_start = byte_for(base);
208 uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size);
209 _committed[res].set_start((HeapWord*)ct_start_aligned);
210 _committed[res].set_word_size(0);
211 return res;
212 }
213
214 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) {
215 for (int i = 0; i < _cur_covered_regions; i++) {
216 if (_covered[i].contains(addr)) {
217 return i;
218 }
219 }
220 assert(0, "address outside of heap?");
221 return -1;
222 }
223
224 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const {
225 HeapWord* max_end = NULL;
226 for (int j = 0; j < ind; j++) {
227 HeapWord* this_end = _committed[j].end();
228 if (this_end > max_end) max_end = this_end;
229 }
230 return max_end;
231 }
232
233 MemRegion CardTableModRefBS::committed_unique_to_self(int self,
234 MemRegion mr) const {
235 MemRegion result = mr;
236 for (int r = 0; r < _cur_covered_regions; r += 1) {
237 if (r != self) {
238 result = result.minus(_committed[r]);
239 }
240 }
241 // Never include the guard page.
242 result = result.minus(_guard_region);
243 return result;
244 }
245
246 void CardTableModRefBS::resize_covered_region(MemRegion new_region) {
247 // We don't change the start of a region, only the end.
248 assert(_whole_heap.contains(new_region),
249 "attempt to cover area not in reserved area");
250 debug_only(verify_guard();)
251 // collided is true if the expansion would push into another committed region
252 debug_only(bool collided = false;)
253 int const ind = find_covering_region_by_base(new_region.start());
254 MemRegion const old_region = _covered[ind];
255 assert(old_region.start() == new_region.start(), "just checking");
256 if (new_region.word_size() != old_region.word_size()) {
257 // Commit new or uncommit old pages, if necessary.
258 MemRegion cur_committed = _committed[ind];
259 // Extend the end of this _committed region
260 // to cover the end of any lower _committed regions.
261 // This forms overlapping regions, but never interior regions.
262 HeapWord* const max_prev_end = largest_prev_committed_end(ind);
263 if (max_prev_end > cur_committed.end()) {
264 cur_committed.set_end(max_prev_end);
265 }
266 // Align the end up to a page size (starts are already aligned).
267 jbyte* const new_end = byte_after(new_region.last());
268 HeapWord* new_end_aligned =
269 (HeapWord*) align_size_up((uintptr_t)new_end, _page_size);
270 assert(new_end_aligned >= (HeapWord*) new_end,
271 "align up, but less");
272 // Check the other regions (excludes "ind") to ensure that
273 // the new_end_aligned does not intrude onto the committed
274 // space of another region.
275 int ri = 0;
276 for (ri = ind + 1; ri < _cur_covered_regions; ri++) {
277 if (new_end_aligned > _committed[ri].start()) {
278 assert(new_end_aligned <= _committed[ri].end(),
279 "An earlier committed region can't cover a later committed region");
280 // Any region containing the new end
281 // should start at or beyond the region found (ind)
282 // for the new end (committed regions are not expected to
283 // be proper subsets of other committed regions).
284 assert(_committed[ri].start() >= _committed[ind].start(),
285 "New end of committed region is inconsistent");
286 new_end_aligned = _committed[ri].start();
287 // new_end_aligned can be equal to the start of its
288 // committed region (i.e., of "ind") if a second
289 // region following "ind" also start at the same location
290 // as "ind".
291 assert(new_end_aligned >= _committed[ind].start(),
292 "New end of committed region is before start");
293 debug_only(collided = true;)
294 // Should only collide with 1 region
295 break;
296 }
297 }
298 #ifdef ASSERT
299 for (++ri; ri < _cur_covered_regions; ri++) {
300 assert(!_committed[ri].contains(new_end_aligned),
301 "New end of committed region is in a second committed region");
302 }
303 #endif
304 // The guard page is always committed and should not be committed over.
305 // "guarded" is used for assertion checking below and recalls the fact
306 // that the would-be end of the new committed region would have
307 // penetrated the guard page.
308 HeapWord* new_end_for_commit = new_end_aligned;
309
310 DEBUG_ONLY(bool guarded = false;)
311 if (new_end_for_commit > _guard_region.start()) {
312 new_end_for_commit = _guard_region.start();
313 DEBUG_ONLY(guarded = true;)
314 }
315
316 if (new_end_for_commit > cur_committed.end()) {
317 // Must commit new pages.
318 MemRegion const new_committed =
319 MemRegion(cur_committed.end(), new_end_for_commit);
320
321 assert(!new_committed.is_empty(), "Region should not be empty here");
322 os::commit_memory_or_exit((char*)new_committed.start(),
323 new_committed.byte_size(), _page_size,
324 !ExecMem, "card table expansion");
325 // Use new_end_aligned (as opposed to new_end_for_commit) because
326 // the cur_committed region may include the guard region.
327 } else if (new_end_aligned < cur_committed.end()) {
328 // Must uncommit pages.
329 MemRegion const uncommit_region =
330 committed_unique_to_self(ind, MemRegion(new_end_aligned,
331 cur_committed.end()));
332 if (!uncommit_region.is_empty()) {
333 // It is not safe to uncommit cards if the boundary between
334 // the generations is moving. A shrink can uncommit cards
335 // owned by generation A but being used by generation B.
336 if (!UseAdaptiveGCBoundary) {
337 if (!os::uncommit_memory((char*)uncommit_region.start(),
338 uncommit_region.byte_size())) {
339 assert(false, "Card table contraction failed");
340 // The call failed so don't change the end of the
341 // committed region. This is better than taking the
342 // VM down.
343 new_end_aligned = _committed[ind].end();
344 }
345 } else {
346 new_end_aligned = _committed[ind].end();
347 }
348 }
349 }
350 // In any case, we can reset the end of the current committed entry.
351 _committed[ind].set_end(new_end_aligned);
352
353 #ifdef ASSERT
354 // Check that the last card in the new region is committed according
355 // to the tables.
356 bool covered = false;
357 for (int cr = 0; cr < _cur_covered_regions; cr++) {
358 if (_committed[cr].contains(new_end - 1)) {
359 covered = true;
360 break;
361 }
362 }
363 assert(covered, "Card for end of new region not committed");
364 #endif
365
366 // The default of 0 is not necessarily clean cards.
367 jbyte* entry;
368 if (old_region.last() < _whole_heap.start()) {
369 entry = byte_for(_whole_heap.start());
370 } else {
371 entry = byte_after(old_region.last());
372 }
373 assert(index_for(new_region.last()) < _guard_index,
374 "The guard card will be overwritten");
375 // This line commented out cleans the newly expanded region and
376 // not the aligned up expanded region.
377 // jbyte* const end = byte_after(new_region.last());
378 jbyte* const end = (jbyte*) new_end_for_commit;
379 assert((end >= byte_after(new_region.last())) || collided || guarded,
380 "Expect to be beyond new region unless impacting another region");
381 // do nothing if we resized downward.
382 #ifdef ASSERT
383 for (int ri = 0; ri < _cur_covered_regions; ri++) {
384 if (ri != ind) {
385 // The end of the new committed region should not
386 // be in any existing region unless it matches
387 // the start of the next region.
388 assert(!_committed[ri].contains(end) ||
389 (_committed[ri].start() == (HeapWord*) end),
390 "Overlapping committed regions");
391 }
392 }
393 #endif
394 if (entry < end) {
395 memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte)));
396 }
397 }
398 // In any case, the covered size changes.
399 _covered[ind].set_word_size(new_region.word_size());
400 if (TraceCardTableModRefBS) {
401 gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: ");
402 gclog_or_tty->print_cr(" "
403 " _covered[%d].start(): " INTPTR_FORMAT
404 " _covered[%d].last(): " INTPTR_FORMAT,
405 ind, p2i(_covered[ind].start()),
406 ind, p2i(_covered[ind].last()));
407 gclog_or_tty->print_cr(" "
408 " _committed[%d].start(): " INTPTR_FORMAT
409 " _committed[%d].last(): " INTPTR_FORMAT,
410 ind, p2i(_committed[ind].start()),
411 ind, p2i(_committed[ind].last()));
412 gclog_or_tty->print_cr(" "
413 " byte_for(start): " INTPTR_FORMAT
414 " byte_for(last): " INTPTR_FORMAT,
415 p2i(byte_for(_covered[ind].start())),
416 p2i(byte_for(_covered[ind].last())));
417 gclog_or_tty->print_cr(" "
418 " addr_for(start): " INTPTR_FORMAT
419 " addr_for(last): " INTPTR_FORMAT,
420 p2i(addr_for((jbyte*) _committed[ind].start())),
421 p2i(addr_for((jbyte*) _committed[ind].last())));
422 }
423 // Touch the last card of the covered region to show that it
424 // is committed (or SEGV).
425 debug_only((void) (*byte_for(_covered[ind].last()));)
426 debug_only(verify_guard();)
427 }
428
429 // Note that these versions are precise! The scanning code has to handle the
430 // fact that the write barrier may be either precise or imprecise.
431
432 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal, bool release) {
433 inline_write_ref_field(field, newVal, release);
434 }
435
436
437 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp,
438 MemRegion mr,
439 OopsInGenClosure* cl,
440 CardTableRS* ct) {
441 if (!mr.is_empty()) {
442 // Caller (process_roots()) claims that all GC threads
443 // execute this call. With UseDynamicNumberOfGCThreads now all
444 // active GC threads execute this call. The number of active GC
445 // threads needs to be passed to par_non_clean_card_iterate_work()
446 // to get proper partitioning and termination.
447 //
448 // This is an example of where n_par_threads() is used instead
449 // of workers()->active_workers(). n_par_threads can be set to 0 to
450 // turn off parallelism. For example when this code is called as
451 // part of verification and SharedHeap::process_roots() is being
452 // used, then n_par_threads() may have been set to 0. active_workers
453 // is not overloaded with the meaning that it is a switch to disable
454 // parallelism and so keeps the meaning of the number of
455 // active gc workers. If parallelism has not been shut off by
456 // setting n_par_threads to 0, then n_par_threads should be
457 // equal to active_workers. When a different mechanism for shutting
458 // off parallelism is used, then active_workers can be used in
459 // place of n_par_threads.
460 int n_threads = SharedHeap::heap()->n_par_threads();
461 bool is_par = n_threads > 0;
462 if (is_par) {
463 #if INCLUDE_ALL_GCS
464 assert(SharedHeap::heap()->n_par_threads() ==
465 SharedHeap::heap()->workers()->active_workers(), "Mismatch");
466 non_clean_card_iterate_parallel_work(sp, mr, cl, ct, n_threads);
467 #else // INCLUDE_ALL_GCS
468 fatal("Parallel gc not supported here.");
469 #endif // INCLUDE_ALL_GCS
470 } else {
471 // We do not call the non_clean_card_iterate_serial() version below because
472 // we want to clear the cards (which non_clean_card_iterate_serial() does not
473 // do for us): clear_cl here does the work of finding contiguous dirty ranges
474 // of cards to process and clear.
475
476 DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(),
477 cl->gen_boundary());
478 ClearNoncleanCardWrapper clear_cl(dcto_cl, ct);
479
480 clear_cl.do_MemRegion(mr);
481 }
482 }
483 }
484
485 // The iterator itself is not MT-aware, but
486 // MT-aware callers and closures can use this to
487 // accomplish dirty card iteration in parallel. The
488 // iterator itself does not clear the dirty cards, or
489 // change their values in any manner.
490 void CardTableModRefBS::non_clean_card_iterate_serial(MemRegion mr,
491 MemRegionClosure* cl) {
492 bool is_par = (SharedHeap::heap()->n_par_threads() > 0);
493 assert(!is_par ||
494 (SharedHeap::heap()->n_par_threads() ==
495 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
496 for (int i = 0; i < _cur_covered_regions; i++) {
497 MemRegion mri = mr.intersection(_covered[i]);
498 if (mri.word_size() > 0) {
499 jbyte* cur_entry = byte_for(mri.last());
500 jbyte* limit = byte_for(mri.start());
501 while (cur_entry >= limit) {
502 jbyte* next_entry = cur_entry - 1;
503 if (*cur_entry != clean_card) {
504 size_t non_clean_cards = 1;
505 // Should the next card be included in this range of dirty cards.
506 while (next_entry >= limit && *next_entry != clean_card) {
507 non_clean_cards++;
508 cur_entry = next_entry;
509 next_entry--;
510 }
511 // The memory region may not be on a card boundary. So that
512 // objects beyond the end of the region are not processed, make
513 // cur_cards precise with regard to the end of the memory region.
514 MemRegion cur_cards(addr_for(cur_entry),
515 non_clean_cards * card_size_in_words);
516 MemRegion dirty_region = cur_cards.intersection(mri);
517 cl->do_MemRegion(dirty_region);
518 }
519 cur_entry = next_entry;
520 }
521 }
522 }
523 }
524
525 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) {
526 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
527 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
528 jbyte* cur = byte_for(mr.start());
529 jbyte* last = byte_after(mr.last());
530 while (cur < last) {
531 *cur = dirty_card;
532 cur++;
533 }
534 }
535
536 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) {
537 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
538 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
539 for (int i = 0; i < _cur_covered_regions; i++) {
540 MemRegion mri = mr.intersection(_covered[i]);
541 if (!mri.is_empty()) dirty_MemRegion(mri);
542 }
543 }
544
545 void CardTableModRefBS::clear_MemRegion(MemRegion mr) {
546 // Be conservative: only clean cards entirely contained within the
547 // region.
548 jbyte* cur;
549 if (mr.start() == _whole_heap.start()) {
550 cur = byte_for(mr.start());
551 } else {
552 assert(mr.start() > _whole_heap.start(), "mr is not covered.");
553 cur = byte_after(mr.start() - 1);
554 }
555 jbyte* last = byte_after(mr.last());
556 memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte)));
557 }
558
559 void CardTableModRefBS::clear(MemRegion mr) {
560 for (int i = 0; i < _cur_covered_regions; i++) {
561 MemRegion mri = mr.intersection(_covered[i]);
562 if (!mri.is_empty()) clear_MemRegion(mri);
563 }
564 }
565
566 void CardTableModRefBS::dirty(MemRegion mr) {
567 jbyte* first = byte_for(mr.start());
568 jbyte* last = byte_after(mr.last());
569 memset(first, dirty_card, last-first);
570 }
571
572 // Unlike several other card table methods, dirty_card_iterate()
573 // iterates over dirty cards ranges in increasing address order.
574 void CardTableModRefBS::dirty_card_iterate(MemRegion mr,
575 MemRegionClosure* cl) {
576 for (int i = 0; i < _cur_covered_regions; i++) {
577 MemRegion mri = mr.intersection(_covered[i]);
578 if (!mri.is_empty()) {
579 jbyte *cur_entry, *next_entry, *limit;
580 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
581 cur_entry <= limit;
582 cur_entry = next_entry) {
583 next_entry = cur_entry + 1;
584 if (*cur_entry == dirty_card) {
585 size_t dirty_cards;
586 // Accumulate maximal dirty card range, starting at cur_entry
587 for (dirty_cards = 1;
588 next_entry <= limit && *next_entry == dirty_card;
589 dirty_cards++, next_entry++);
590 MemRegion cur_cards(addr_for(cur_entry),
591 dirty_cards*card_size_in_words);
592 cl->do_MemRegion(cur_cards);
593 }
594 }
595 }
596 }
597 }
598
599 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr,
600 bool reset,
601 int reset_val) {
602 for (int i = 0; i < _cur_covered_regions; i++) {
603 MemRegion mri = mr.intersection(_covered[i]);
604 if (!mri.is_empty()) {
605 jbyte* cur_entry, *next_entry, *limit;
606 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
607 cur_entry <= limit;
608 cur_entry = next_entry) {
609 next_entry = cur_entry + 1;
610 if (*cur_entry == dirty_card) {
611 size_t dirty_cards;
612 // Accumulate maximal dirty card range, starting at cur_entry
613 for (dirty_cards = 1;
614 next_entry <= limit && *next_entry == dirty_card;
615 dirty_cards++, next_entry++);
616 MemRegion cur_cards(addr_for(cur_entry),
617 dirty_cards*card_size_in_words);
618 if (reset) {
619 for (size_t i = 0; i < dirty_cards; i++) {
620 cur_entry[i] = reset_val;
621 }
622 }
623 return cur_cards;
624 }
625 }
626 }
627 }
628 return MemRegion(mr.end(), mr.end());
629 }
630
631 uintx CardTableModRefBS::ct_max_alignment_constraint() {
632 return card_size * os::vm_page_size();
633 }
634
635 void CardTableModRefBS::verify_guard() {
636 // For product build verification
637 guarantee(_byte_map[_guard_index] == last_card,
638 "card table guard has been modified");
639 }
640
641 void CardTableModRefBS::verify() {
642 verify_guard();
643 }
644
645 #ifndef PRODUCT
646 void CardTableModRefBS::verify_region(MemRegion mr,
647 jbyte val, bool val_equals) {
648 jbyte* start = byte_for(mr.start());
649 jbyte* end = byte_for(mr.last());
650 bool failures = false;
651 for (jbyte* curr = start; curr <= end; ++curr) {
652 jbyte curr_val = *curr;
653 bool failed = (val_equals) ? (curr_val != val) : (curr_val == val);
654 if (failed) {
655 if (!failures) {
656 tty->cr();
657 tty->print_cr("== CT verification failed: [" INTPTR_FORMAT "," INTPTR_FORMAT "]", p2i(start), p2i(end));
658 tty->print_cr("== %sexpecting value: %d",
659 (val_equals) ? "" : "not ", val);
660 failures = true;
661 }
662 tty->print_cr("== card "PTR_FORMAT" ["PTR_FORMAT","PTR_FORMAT"], "
663 "val: %d", p2i(curr), p2i(addr_for(curr)),
664 p2i((HeapWord*) (((size_t) addr_for(curr)) + card_size)),
665 (int) curr_val);
666 }
667 }
668 guarantee(!failures, "there should not have been any failures");
669 }
670
671 void CardTableModRefBS::verify_not_dirty_region(MemRegion mr) {
672 verify_region(mr, dirty_card, false /* val_equals */);
673 }
674
675 void CardTableModRefBS::verify_dirty_region(MemRegion mr) {
676 verify_region(mr, dirty_card, true /* val_equals */);
677 }
678 #endif
679
680 void CardTableModRefBS::print_on(outputStream* st) const {
681 st->print_cr("Card table byte_map: [" INTPTR_FORMAT "," INTPTR_FORMAT "] byte_map_base: " INTPTR_FORMAT,
682 p2i(_byte_map), p2i(_byte_map + _byte_map_size), p2i(byte_map_base));
683 }
684
685 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) {
686 return
687 CardTableModRefBS::card_will_be_scanned(cv) ||
688 _rs->is_prev_nonclean_card_val(cv);
689 };
690
691 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) {
692 return
693 cv != clean_card &&
694 (CardTableModRefBS::card_may_have_been_dirty(cv) ||
695 CardTableRS::youngergen_may_have_been_dirty(cv));
696 };