Thu, 26 Jun 2014 11:36:58 +0200
8047818: G1 HeapRegions can no longer be ContiguousSpaces
Summary: Change parent of G1OffsetTableContigSpace to CompactibleSpace, reimplement missing functionality
Reviewed-by: stefank, jmasa, tschatzl
1 /*
2 * Copyright (c) 2000, 2014, 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 */
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/cardTableModRefBS.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
43 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
44 // enumerate ref fields that have been modified (since the last
45 // enumeration.)
47 size_t CardTableModRefBS::cards_required(size_t covered_words)
48 {
49 // Add one for a guard card, used to detect errors.
50 const size_t words = align_size_up(covered_words, card_size_in_words);
51 return words / card_size_in_words + 1;
52 }
54 size_t CardTableModRefBS::compute_byte_map_size()
55 {
56 assert(_guard_index == cards_required(_whole_heap.word_size()) - 1,
57 "unitialized, check declaration order");
58 assert(_page_size != 0, "unitialized, check declaration order");
59 const size_t granularity = os::vm_allocation_granularity();
60 return align_size_up(_guard_index + 1, MAX2(_page_size, granularity));
61 }
63 CardTableModRefBS::CardTableModRefBS(MemRegion whole_heap,
64 int max_covered_regions):
65 ModRefBarrierSet(max_covered_regions),
66 _whole_heap(whole_heap),
67 _guard_index(cards_required(whole_heap.word_size()) - 1),
68 _last_valid_index(_guard_index - 1),
69 _page_size(os::vm_page_size()),
70 _byte_map_size(compute_byte_map_size())
71 {
72 _kind = BarrierSet::CardTableModRef;
74 HeapWord* low_bound = _whole_heap.start();
75 HeapWord* high_bound = _whole_heap.end();
76 assert((uintptr_t(low_bound) & (card_size - 1)) == 0, "heap must start at card boundary");
77 assert((uintptr_t(high_bound) & (card_size - 1)) == 0, "heap must end at card boundary");
79 assert(card_size <= 512, "card_size must be less than 512"); // why?
81 _covered = new MemRegion[max_covered_regions];
82 _committed = new MemRegion[max_covered_regions];
83 if (_covered == NULL || _committed == NULL) {
84 vm_exit_during_initialization("couldn't alloc card table covered region set.");
85 }
87 _cur_covered_regions = 0;
88 const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 :
89 MAX2(_page_size, (size_t) os::vm_allocation_granularity());
90 ReservedSpace heap_rs(_byte_map_size, rs_align, false);
92 MemTracker::record_virtual_memory_type((address)heap_rs.base(), mtGC);
94 os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1,
95 _page_size, heap_rs.base(), heap_rs.size());
96 if (!heap_rs.is_reserved()) {
97 vm_exit_during_initialization("Could not reserve enough space for the "
98 "card marking array");
99 }
101 // The assember store_check code will do an unsigned shift of the oop,
102 // then add it to byte_map_base, i.e.
103 //
104 // _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift)
105 _byte_map = (jbyte*) heap_rs.base();
106 byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
107 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
108 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
110 jbyte* guard_card = &_byte_map[_guard_index];
111 uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size);
112 _guard_region = MemRegion((HeapWord*)guard_page, _page_size);
113 os::commit_memory_or_exit((char*)guard_page, _page_size, _page_size,
114 !ExecMem, "card table last card");
115 *guard_card = last_card;
117 _lowest_non_clean =
118 NEW_C_HEAP_ARRAY(CardArr, max_covered_regions, mtGC);
119 _lowest_non_clean_chunk_size =
120 NEW_C_HEAP_ARRAY(size_t, max_covered_regions, mtGC);
121 _lowest_non_clean_base_chunk_index =
122 NEW_C_HEAP_ARRAY(uintptr_t, max_covered_regions, mtGC);
123 _last_LNC_resizing_collection =
124 NEW_C_HEAP_ARRAY(int, max_covered_regions, mtGC);
125 if (_lowest_non_clean == NULL
126 || _lowest_non_clean_chunk_size == NULL
127 || _lowest_non_clean_base_chunk_index == NULL
128 || _last_LNC_resizing_collection == NULL)
129 vm_exit_during_initialization("couldn't allocate an LNC array.");
130 for (int i = 0; i < max_covered_regions; i++) {
131 _lowest_non_clean[i] = NULL;
132 _lowest_non_clean_chunk_size[i] = 0;
133 _last_LNC_resizing_collection[i] = -1;
134 }
136 if (TraceCardTableModRefBS) {
137 gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: ");
138 gclog_or_tty->print_cr(" "
139 " &_byte_map[0]: " INTPTR_FORMAT
140 " &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
141 p2i(&_byte_map[0]),
142 p2i(&_byte_map[_last_valid_index]));
143 gclog_or_tty->print_cr(" "
144 " byte_map_base: " INTPTR_FORMAT,
145 p2i(byte_map_base));
146 }
147 }
149 CardTableModRefBS::~CardTableModRefBS() {
150 if (_covered) {
151 delete[] _covered;
152 _covered = NULL;
153 }
154 if (_committed) {
155 delete[] _committed;
156 _committed = NULL;
157 }
158 if (_lowest_non_clean) {
159 FREE_C_HEAP_ARRAY(CardArr, _lowest_non_clean, mtGC);
160 _lowest_non_clean = NULL;
161 }
162 if (_lowest_non_clean_chunk_size) {
163 FREE_C_HEAP_ARRAY(size_t, _lowest_non_clean_chunk_size, mtGC);
164 _lowest_non_clean_chunk_size = NULL;
165 }
166 if (_lowest_non_clean_base_chunk_index) {
167 FREE_C_HEAP_ARRAY(uintptr_t, _lowest_non_clean_base_chunk_index, mtGC);
168 _lowest_non_clean_base_chunk_index = NULL;
169 }
170 if (_last_LNC_resizing_collection) {
171 FREE_C_HEAP_ARRAY(int, _last_LNC_resizing_collection, mtGC);
172 _last_LNC_resizing_collection = NULL;
173 }
174 }
176 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) {
177 int i;
178 for (i = 0; i < _cur_covered_regions; i++) {
179 if (_covered[i].start() == base) return i;
180 if (_covered[i].start() > base) break;
181 }
182 // If we didn't find it, create a new one.
183 assert(_cur_covered_regions < _max_covered_regions,
184 "too many covered regions");
185 // Move the ones above up, to maintain sorted order.
186 for (int j = _cur_covered_regions; j > i; j--) {
187 _covered[j] = _covered[j-1];
188 _committed[j] = _committed[j-1];
189 }
190 int res = i;
191 _cur_covered_regions++;
192 _covered[res].set_start(base);
193 _covered[res].set_word_size(0);
194 jbyte* ct_start = byte_for(base);
195 uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size);
196 _committed[res].set_start((HeapWord*)ct_start_aligned);
197 _committed[res].set_word_size(0);
198 return res;
199 }
201 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) {
202 for (int i = 0; i < _cur_covered_regions; i++) {
203 if (_covered[i].contains(addr)) {
204 return i;
205 }
206 }
207 assert(0, "address outside of heap?");
208 return -1;
209 }
211 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const {
212 HeapWord* max_end = NULL;
213 for (int j = 0; j < ind; j++) {
214 HeapWord* this_end = _committed[j].end();
215 if (this_end > max_end) max_end = this_end;
216 }
217 return max_end;
218 }
220 MemRegion CardTableModRefBS::committed_unique_to_self(int self,
221 MemRegion mr) const {
222 MemRegion result = mr;
223 for (int r = 0; r < _cur_covered_regions; r += 1) {
224 if (r != self) {
225 result = result.minus(_committed[r]);
226 }
227 }
228 // Never include the guard page.
229 result = result.minus(_guard_region);
230 return result;
231 }
233 void CardTableModRefBS::resize_covered_region(MemRegion new_region) {
234 // We don't change the start of a region, only the end.
235 assert(_whole_heap.contains(new_region),
236 "attempt to cover area not in reserved area");
237 debug_only(verify_guard();)
238 // collided is true if the expansion would push into another committed region
239 debug_only(bool collided = false;)
240 int const ind = find_covering_region_by_base(new_region.start());
241 MemRegion const old_region = _covered[ind];
242 assert(old_region.start() == new_region.start(), "just checking");
243 if (new_region.word_size() != old_region.word_size()) {
244 // Commit new or uncommit old pages, if necessary.
245 MemRegion cur_committed = _committed[ind];
246 // Extend the end of this _commited region
247 // to cover the end of any lower _committed regions.
248 // This forms overlapping regions, but never interior regions.
249 HeapWord* const max_prev_end = largest_prev_committed_end(ind);
250 if (max_prev_end > cur_committed.end()) {
251 cur_committed.set_end(max_prev_end);
252 }
253 // Align the end up to a page size (starts are already aligned).
254 jbyte* const new_end = byte_after(new_region.last());
255 HeapWord* new_end_aligned =
256 (HeapWord*) align_size_up((uintptr_t)new_end, _page_size);
257 assert(new_end_aligned >= (HeapWord*) new_end,
258 "align up, but less");
259 // Check the other regions (excludes "ind") to ensure that
260 // the new_end_aligned does not intrude onto the committed
261 // space of another region.
262 int ri = 0;
263 for (ri = 0; ri < _cur_covered_regions; ri++) {
264 if (ri != ind) {
265 if (_committed[ri].contains(new_end_aligned)) {
266 // The prior check included in the assert
267 // (new_end_aligned >= _committed[ri].start())
268 // is redundant with the "contains" test.
269 // Any region containing the new end
270 // should start at or beyond the region found (ind)
271 // for the new end (committed regions are not expected to
272 // be proper subsets of other committed regions).
273 assert(_committed[ri].start() >= _committed[ind].start(),
274 "New end of committed region is inconsistent");
275 new_end_aligned = _committed[ri].start();
276 // new_end_aligned can be equal to the start of its
277 // committed region (i.e., of "ind") if a second
278 // region following "ind" also start at the same location
279 // as "ind".
280 assert(new_end_aligned >= _committed[ind].start(),
281 "New end of committed region is before start");
282 debug_only(collided = true;)
283 // Should only collide with 1 region
284 break;
285 }
286 }
287 }
288 #ifdef ASSERT
289 for (++ri; ri < _cur_covered_regions; ri++) {
290 assert(!_committed[ri].contains(new_end_aligned),
291 "New end of committed region is in a second committed region");
292 }
293 #endif
294 // The guard page is always committed and should not be committed over.
295 // "guarded" is used for assertion checking below and recalls the fact
296 // that the would-be end of the new committed region would have
297 // penetrated the guard page.
298 HeapWord* new_end_for_commit = new_end_aligned;
300 DEBUG_ONLY(bool guarded = false;)
301 if (new_end_for_commit > _guard_region.start()) {
302 new_end_for_commit = _guard_region.start();
303 DEBUG_ONLY(guarded = true;)
304 }
306 if (new_end_for_commit > cur_committed.end()) {
307 // Must commit new pages.
308 MemRegion const new_committed =
309 MemRegion(cur_committed.end(), new_end_for_commit);
311 assert(!new_committed.is_empty(), "Region should not be empty here");
312 os::commit_memory_or_exit((char*)new_committed.start(),
313 new_committed.byte_size(), _page_size,
314 !ExecMem, "card table expansion");
315 // Use new_end_aligned (as opposed to new_end_for_commit) because
316 // the cur_committed region may include the guard region.
317 } else if (new_end_aligned < cur_committed.end()) {
318 // Must uncommit pages.
319 MemRegion const uncommit_region =
320 committed_unique_to_self(ind, MemRegion(new_end_aligned,
321 cur_committed.end()));
322 if (!uncommit_region.is_empty()) {
323 // It is not safe to uncommit cards if the boundary between
324 // the generations is moving. A shrink can uncommit cards
325 // owned by generation A but being used by generation B.
326 if (!UseAdaptiveGCBoundary) {
327 if (!os::uncommit_memory((char*)uncommit_region.start(),
328 uncommit_region.byte_size())) {
329 assert(false, "Card table contraction failed");
330 // The call failed so don't change the end of the
331 // committed region. This is better than taking the
332 // VM down.
333 new_end_aligned = _committed[ind].end();
334 }
335 } else {
336 new_end_aligned = _committed[ind].end();
337 }
338 }
339 }
340 // In any case, we can reset the end of the current committed entry.
341 _committed[ind].set_end(new_end_aligned);
343 #ifdef ASSERT
344 // Check that the last card in the new region is committed according
345 // to the tables.
346 bool covered = false;
347 for (int cr = 0; cr < _cur_covered_regions; cr++) {
348 if (_committed[cr].contains(new_end - 1)) {
349 covered = true;
350 break;
351 }
352 }
353 assert(covered, "Card for end of new region not committed");
354 #endif
356 // The default of 0 is not necessarily clean cards.
357 jbyte* entry;
358 if (old_region.last() < _whole_heap.start()) {
359 entry = byte_for(_whole_heap.start());
360 } else {
361 entry = byte_after(old_region.last());
362 }
363 assert(index_for(new_region.last()) < _guard_index,
364 "The guard card will be overwritten");
365 // This line commented out cleans the newly expanded region and
366 // not the aligned up expanded region.
367 // jbyte* const end = byte_after(new_region.last());
368 jbyte* const end = (jbyte*) new_end_for_commit;
369 assert((end >= byte_after(new_region.last())) || collided || guarded,
370 "Expect to be beyond new region unless impacting another region");
371 // do nothing if we resized downward.
372 #ifdef ASSERT
373 for (int ri = 0; ri < _cur_covered_regions; ri++) {
374 if (ri != ind) {
375 // The end of the new committed region should not
376 // be in any existing region unless it matches
377 // the start of the next region.
378 assert(!_committed[ri].contains(end) ||
379 (_committed[ri].start() == (HeapWord*) end),
380 "Overlapping committed regions");
381 }
382 }
383 #endif
384 if (entry < end) {
385 memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte)));
386 }
387 }
388 // In any case, the covered size changes.
389 _covered[ind].set_word_size(new_region.word_size());
390 if (TraceCardTableModRefBS) {
391 gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: ");
392 gclog_or_tty->print_cr(" "
393 " _covered[%d].start(): " INTPTR_FORMAT
394 " _covered[%d].last(): " INTPTR_FORMAT,
395 ind, p2i(_covered[ind].start()),
396 ind, p2i(_covered[ind].last()));
397 gclog_or_tty->print_cr(" "
398 " _committed[%d].start(): " INTPTR_FORMAT
399 " _committed[%d].last(): " INTPTR_FORMAT,
400 ind, p2i(_committed[ind].start()),
401 ind, p2i(_committed[ind].last()));
402 gclog_or_tty->print_cr(" "
403 " byte_for(start): " INTPTR_FORMAT
404 " byte_for(last): " INTPTR_FORMAT,
405 p2i(byte_for(_covered[ind].start())),
406 p2i(byte_for(_covered[ind].last())));
407 gclog_or_tty->print_cr(" "
408 " addr_for(start): " INTPTR_FORMAT
409 " addr_for(last): " INTPTR_FORMAT,
410 p2i(addr_for((jbyte*) _committed[ind].start())),
411 p2i(addr_for((jbyte*) _committed[ind].last())));
412 }
413 // Touch the last card of the covered region to show that it
414 // is committed (or SEGV).
415 debug_only((void) (*byte_for(_covered[ind].last()));)
416 debug_only(verify_guard();)
417 }
419 // Note that these versions are precise! The scanning code has to handle the
420 // fact that the write barrier may be either precise or imprecise.
422 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal, bool release) {
423 inline_write_ref_field(field, newVal, release);
424 }
427 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp,
428 MemRegion mr,
429 OopsInGenClosure* cl,
430 CardTableRS* ct) {
431 if (!mr.is_empty()) {
432 // Caller (process_strong_roots()) claims that all GC threads
433 // execute this call. With UseDynamicNumberOfGCThreads now all
434 // active GC threads execute this call. The number of active GC
435 // threads needs to be passed to par_non_clean_card_iterate_work()
436 // to get proper partitioning and termination.
437 //
438 // This is an example of where n_par_threads() is used instead
439 // of workers()->active_workers(). n_par_threads can be set to 0 to
440 // turn off parallelism. For example when this code is called as
441 // part of verification and SharedHeap::process_strong_roots() is being
442 // used, then n_par_threads() may have been set to 0. active_workers
443 // is not overloaded with the meaning that it is a switch to disable
444 // parallelism and so keeps the meaning of the number of
445 // active gc workers. If parallelism has not been shut off by
446 // setting n_par_threads to 0, then n_par_threads should be
447 // equal to active_workers. When a different mechanism for shutting
448 // off parallelism is used, then active_workers can be used in
449 // place of n_par_threads.
450 // This is an example of a path where n_par_threads is
451 // set to 0 to turn off parallism.
452 // [7] CardTableModRefBS::non_clean_card_iterate()
453 // [8] CardTableRS::younger_refs_in_space_iterate()
454 // [9] Generation::younger_refs_in_space_iterate()
455 // [10] OneContigSpaceCardGeneration::younger_refs_iterate()
456 // [11] CompactingPermGenGen::younger_refs_iterate()
457 // [12] CardTableRS::younger_refs_iterate()
458 // [13] SharedHeap::process_strong_roots()
459 // [14] G1CollectedHeap::verify()
460 // [15] Universe::verify()
461 // [16] G1CollectedHeap::do_collection_pause_at_safepoint()
462 //
463 int n_threads = SharedHeap::heap()->n_par_threads();
464 bool is_par = n_threads > 0;
465 if (is_par) {
466 #if INCLUDE_ALL_GCS
467 assert(SharedHeap::heap()->n_par_threads() ==
468 SharedHeap::heap()->workers()->active_workers(), "Mismatch");
469 non_clean_card_iterate_parallel_work(sp, mr, cl, ct, n_threads);
470 #else // INCLUDE_ALL_GCS
471 fatal("Parallel gc not supported here.");
472 #endif // INCLUDE_ALL_GCS
473 } else {
474 // We do not call the non_clean_card_iterate_serial() version below because
475 // we want to clear the cards (which non_clean_card_iterate_serial() does not
476 // do for us): clear_cl here does the work of finding contiguous dirty ranges
477 // of cards to process and clear.
479 DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(),
480 cl->gen_boundary());
481 ClearNoncleanCardWrapper clear_cl(dcto_cl, ct);
483 clear_cl.do_MemRegion(mr);
484 }
485 }
486 }
488 // The iterator itself is not MT-aware, but
489 // MT-aware callers and closures can use this to
490 // accomplish dirty card iteration in parallel. The
491 // iterator itself does not clear the dirty cards, or
492 // change their values in any manner.
493 void CardTableModRefBS::non_clean_card_iterate_serial(MemRegion mr,
494 MemRegionClosure* cl) {
495 bool is_par = (SharedHeap::heap()->n_par_threads() > 0);
496 assert(!is_par ||
497 (SharedHeap::heap()->n_par_threads() ==
498 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
499 for (int i = 0; i < _cur_covered_regions; i++) {
500 MemRegion mri = mr.intersection(_covered[i]);
501 if (mri.word_size() > 0) {
502 jbyte* cur_entry = byte_for(mri.last());
503 jbyte* limit = byte_for(mri.start());
504 while (cur_entry >= limit) {
505 jbyte* next_entry = cur_entry - 1;
506 if (*cur_entry != clean_card) {
507 size_t non_clean_cards = 1;
508 // Should the next card be included in this range of dirty cards.
509 while (next_entry >= limit && *next_entry != clean_card) {
510 non_clean_cards++;
511 cur_entry = next_entry;
512 next_entry--;
513 }
514 // The memory region may not be on a card boundary. So that
515 // objects beyond the end of the region are not processed, make
516 // cur_cards precise with regard to the end of the memory region.
517 MemRegion cur_cards(addr_for(cur_entry),
518 non_clean_cards * card_size_in_words);
519 MemRegion dirty_region = cur_cards.intersection(mri);
520 cl->do_MemRegion(dirty_region);
521 }
522 cur_entry = next_entry;
523 }
524 }
525 }
526 }
528 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) {
529 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
530 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
531 jbyte* cur = byte_for(mr.start());
532 jbyte* last = byte_after(mr.last());
533 while (cur < last) {
534 *cur = dirty_card;
535 cur++;
536 }
537 }
539 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) {
540 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
541 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" );
542 for (int i = 0; i < _cur_covered_regions; i++) {
543 MemRegion mri = mr.intersection(_covered[i]);
544 if (!mri.is_empty()) dirty_MemRegion(mri);
545 }
546 }
548 void CardTableModRefBS::clear_MemRegion(MemRegion mr) {
549 // Be conservative: only clean cards entirely contained within the
550 // region.
551 jbyte* cur;
552 if (mr.start() == _whole_heap.start()) {
553 cur = byte_for(mr.start());
554 } else {
555 assert(mr.start() > _whole_heap.start(), "mr is not covered.");
556 cur = byte_after(mr.start() - 1);
557 }
558 jbyte* last = byte_after(mr.last());
559 memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte)));
560 }
562 void CardTableModRefBS::clear(MemRegion mr) {
563 for (int i = 0; i < _cur_covered_regions; i++) {
564 MemRegion mri = mr.intersection(_covered[i]);
565 if (!mri.is_empty()) clear_MemRegion(mri);
566 }
567 }
569 void CardTableModRefBS::dirty(MemRegion mr) {
570 jbyte* first = byte_for(mr.start());
571 jbyte* last = byte_after(mr.last());
572 memset(first, dirty_card, last-first);
573 }
575 // Unlike several other card table methods, dirty_card_iterate()
576 // iterates over dirty cards ranges in increasing address order.
577 void CardTableModRefBS::dirty_card_iterate(MemRegion mr,
578 MemRegionClosure* cl) {
579 for (int i = 0; i < _cur_covered_regions; i++) {
580 MemRegion mri = mr.intersection(_covered[i]);
581 if (!mri.is_empty()) {
582 jbyte *cur_entry, *next_entry, *limit;
583 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
584 cur_entry <= limit;
585 cur_entry = next_entry) {
586 next_entry = cur_entry + 1;
587 if (*cur_entry == dirty_card) {
588 size_t dirty_cards;
589 // Accumulate maximal dirty card range, starting at cur_entry
590 for (dirty_cards = 1;
591 next_entry <= limit && *next_entry == dirty_card;
592 dirty_cards++, next_entry++);
593 MemRegion cur_cards(addr_for(cur_entry),
594 dirty_cards*card_size_in_words);
595 cl->do_MemRegion(cur_cards);
596 }
597 }
598 }
599 }
600 }
602 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr,
603 bool reset,
604 int reset_val) {
605 for (int i = 0; i < _cur_covered_regions; i++) {
606 MemRegion mri = mr.intersection(_covered[i]);
607 if (!mri.is_empty()) {
608 jbyte* cur_entry, *next_entry, *limit;
609 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
610 cur_entry <= limit;
611 cur_entry = next_entry) {
612 next_entry = cur_entry + 1;
613 if (*cur_entry == dirty_card) {
614 size_t dirty_cards;
615 // Accumulate maximal dirty card range, starting at cur_entry
616 for (dirty_cards = 1;
617 next_entry <= limit && *next_entry == dirty_card;
618 dirty_cards++, next_entry++);
619 MemRegion cur_cards(addr_for(cur_entry),
620 dirty_cards*card_size_in_words);
621 if (reset) {
622 for (size_t i = 0; i < dirty_cards; i++) {
623 cur_entry[i] = reset_val;
624 }
625 }
626 return cur_cards;
627 }
628 }
629 }
630 }
631 return MemRegion(mr.end(), mr.end());
632 }
634 uintx CardTableModRefBS::ct_max_alignment_constraint() {
635 return card_size * os::vm_page_size();
636 }
638 void CardTableModRefBS::verify_guard() {
639 // For product build verification
640 guarantee(_byte_map[_guard_index] == last_card,
641 "card table guard has been modified");
642 }
644 void CardTableModRefBS::verify() {
645 verify_guard();
646 }
648 #ifndef PRODUCT
649 void CardTableModRefBS::verify_region(MemRegion mr,
650 jbyte val, bool val_equals) {
651 jbyte* start = byte_for(mr.start());
652 jbyte* end = byte_for(mr.last());
653 bool failures = false;
654 for (jbyte* curr = start; curr <= end; ++curr) {
655 jbyte curr_val = *curr;
656 bool failed = (val_equals) ? (curr_val != val) : (curr_val == val);
657 if (failed) {
658 if (!failures) {
659 tty->cr();
660 tty->print_cr("== CT verification failed: [" INTPTR_FORMAT "," INTPTR_FORMAT "]", p2i(start), p2i(end));
661 tty->print_cr("== %sexpecting value: %d",
662 (val_equals) ? "" : "not ", val);
663 failures = true;
664 }
665 tty->print_cr("== card "PTR_FORMAT" ["PTR_FORMAT","PTR_FORMAT"], "
666 "val: %d", p2i(curr), p2i(addr_for(curr)),
667 p2i((HeapWord*) (((size_t) addr_for(curr)) + card_size)),
668 (int) curr_val);
669 }
670 }
671 guarantee(!failures, "there should not have been any failures");
672 }
674 void CardTableModRefBS::verify_not_dirty_region(MemRegion mr) {
675 verify_region(mr, dirty_card, false /* val_equals */);
676 }
678 void CardTableModRefBS::verify_dirty_region(MemRegion mr) {
679 verify_region(mr, dirty_card, true /* val_equals */);
680 }
681 #endif
683 void CardTableModRefBS::print_on(outputStream* st) const {
684 st->print_cr("Card table byte_map: [" INTPTR_FORMAT "," INTPTR_FORMAT "] byte_map_base: " INTPTR_FORMAT,
685 p2i(_byte_map), p2i(_byte_map + _byte_map_size), p2i(byte_map_base));
686 }
688 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) {
689 return
690 CardTableModRefBS::card_will_be_scanned(cv) ||
691 _rs->is_prev_nonclean_card_val(cv);
692 };
694 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) {
695 return
696 cv != clean_card &&
697 (CardTableModRefBS::card_may_have_been_dirty(cv) ||
698 CardTableRS::youngergen_may_have_been_dirty(cv));
699 };