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comparison src/share/vm/gc_implementation/parallelScavenge/cardTableExtension.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | ba764ed4b6f2 |
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1 /* | |
2 * Copyright 2001-2006 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 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_cardTableExtension.cpp.incl" | |
27 | |
28 // Checks an individual oop for missing precise marks. Mark | |
29 // may be either dirty or newgen. | |
30 class CheckForUnmarkedOops : public OopClosure { | |
31 PSYoungGen* _young_gen; | |
32 CardTableExtension* _card_table; | |
33 HeapWord* _unmarked_addr; | |
34 jbyte* _unmarked_card; | |
35 | |
36 public: | |
37 CheckForUnmarkedOops( PSYoungGen* young_gen, CardTableExtension* card_table ) : | |
38 _young_gen(young_gen), _card_table(card_table), _unmarked_addr(NULL) { } | |
39 | |
40 virtual void do_oop(oop* p) { | |
41 if (_young_gen->is_in_reserved(*p) && | |
42 !_card_table->addr_is_marked_imprecise(p)) { | |
43 // Don't overwrite the first missing card mark | |
44 if (_unmarked_addr == NULL) { | |
45 _unmarked_addr = (HeapWord*)p; | |
46 _unmarked_card = _card_table->byte_for(p); | |
47 } | |
48 } | |
49 } | |
50 | |
51 bool has_unmarked_oop() { | |
52 return _unmarked_addr != NULL; | |
53 } | |
54 }; | |
55 | |
56 // Checks all objects for the existance of some type of mark, | |
57 // precise or imprecise, dirty or newgen. | |
58 class CheckForUnmarkedObjects : public ObjectClosure { | |
59 PSYoungGen* _young_gen; | |
60 CardTableExtension* _card_table; | |
61 | |
62 public: | |
63 CheckForUnmarkedObjects() { | |
64 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
65 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
66 | |
67 _young_gen = heap->young_gen(); | |
68 _card_table = (CardTableExtension*)heap->barrier_set(); | |
69 // No point in asserting barrier set type here. Need to make CardTableExtension | |
70 // a unique barrier set type. | |
71 } | |
72 | |
73 // Card marks are not precise. The current system can leave us with | |
74 // a mismash of precise marks and begining of object marks. This means | |
75 // we test for missing precise marks first. If any are found, we don't | |
76 // fail unless the object head is also unmarked. | |
77 virtual void do_object(oop obj) { | |
78 CheckForUnmarkedOops object_check( _young_gen, _card_table ); | |
79 obj->oop_iterate(&object_check); | |
80 if (object_check.has_unmarked_oop()) { | |
81 assert(_card_table->addr_is_marked_imprecise(obj), "Found unmarked young_gen object"); | |
82 } | |
83 } | |
84 }; | |
85 | |
86 // Checks for precise marking of oops as newgen. | |
87 class CheckForPreciseMarks : public OopClosure { | |
88 PSYoungGen* _young_gen; | |
89 CardTableExtension* _card_table; | |
90 | |
91 public: | |
92 CheckForPreciseMarks( PSYoungGen* young_gen, CardTableExtension* card_table ) : | |
93 _young_gen(young_gen), _card_table(card_table) { } | |
94 | |
95 virtual void do_oop(oop* p) { | |
96 if (_young_gen->is_in_reserved(*p)) { | |
97 assert(_card_table->addr_is_marked_precise(p), "Found unmarked precise oop"); | |
98 _card_table->set_card_newgen(p); | |
99 } | |
100 } | |
101 }; | |
102 | |
103 // We get passed the space_top value to prevent us from traversing into | |
104 // the old_gen promotion labs, which cannot be safely parsed. | |
105 void CardTableExtension::scavenge_contents(ObjectStartArray* start_array, | |
106 MutableSpace* sp, | |
107 HeapWord* space_top, | |
108 PSPromotionManager* pm) | |
109 { | |
110 assert(start_array != NULL && sp != NULL && pm != NULL, "Sanity"); | |
111 assert(start_array->covered_region().contains(sp->used_region()), | |
112 "ObjectStartArray does not cover space"); | |
113 bool depth_first = pm->depth_first(); | |
114 | |
115 if (sp->not_empty()) { | |
116 oop* sp_top = (oop*)space_top; | |
117 oop* prev_top = NULL; | |
118 jbyte* current_card = byte_for(sp->bottom()); | |
119 jbyte* end_card = byte_for(sp_top - 1); // sp_top is exclusive | |
120 // scan card marking array | |
121 while (current_card <= end_card) { | |
122 jbyte value = *current_card; | |
123 // skip clean cards | |
124 if (card_is_clean(value)) { | |
125 current_card++; | |
126 } else { | |
127 // we found a non-clean card | |
128 jbyte* first_nonclean_card = current_card++; | |
129 oop* bottom = (oop*)addr_for(first_nonclean_card); | |
130 // find object starting on card | |
131 oop* bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom); | |
132 // bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom); | |
133 assert(bottom_obj <= bottom, "just checking"); | |
134 // make sure we don't scan oops we already looked at | |
135 if (bottom < prev_top) bottom = prev_top; | |
136 // figure out when to stop scanning | |
137 jbyte* first_clean_card; | |
138 oop* top; | |
139 bool restart_scanning; | |
140 do { | |
141 restart_scanning = false; | |
142 // find a clean card | |
143 while (current_card <= end_card) { | |
144 value = *current_card; | |
145 if (card_is_clean(value)) break; | |
146 current_card++; | |
147 } | |
148 // check if we reached the end, if so we are done | |
149 if (current_card >= end_card) { | |
150 first_clean_card = end_card + 1; | |
151 current_card++; | |
152 top = sp_top; | |
153 } else { | |
154 // we have a clean card, find object starting on that card | |
155 first_clean_card = current_card++; | |
156 top = (oop*)addr_for(first_clean_card); | |
157 oop* top_obj = (oop*)start_array->object_start((HeapWord*)top); | |
158 // top_obj = (oop*)start_array->object_start((HeapWord*)top); | |
159 assert(top_obj <= top, "just checking"); | |
160 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { | |
161 // an arrayOop is starting on the clean card - since we do exact store | |
162 // checks for objArrays we are done | |
163 } else { | |
164 // otherwise, it is possible that the object starting on the clean card | |
165 // spans the entire card, and that the store happened on a later card. | |
166 // figure out where the object ends | |
167 top = top_obj + oop(top_obj)->size(); | |
168 jbyte* top_card = CardTableModRefBS::byte_for(top - 1); // top is exclusive | |
169 if (top_card > first_clean_card) { | |
170 // object ends a different card | |
171 current_card = top_card + 1; | |
172 if (card_is_clean(*top_card)) { | |
173 // the ending card is clean, we are done | |
174 first_clean_card = top_card; | |
175 } else { | |
176 // the ending card is not clean, continue scanning at start of do-while | |
177 restart_scanning = true; | |
178 } | |
179 } else { | |
180 // object ends on the clean card, we are done. | |
181 assert(first_clean_card == top_card, "just checking"); | |
182 } | |
183 } | |
184 } | |
185 } while (restart_scanning); | |
186 // we know which cards to scan, now clear them | |
187 while (first_nonclean_card < first_clean_card) { | |
188 *first_nonclean_card++ = clean_card; | |
189 } | |
190 // scan oops in objects | |
191 // hoisted the if (depth_first) check out of the loop | |
192 if (depth_first){ | |
193 do { | |
194 oop(bottom_obj)->push_contents(pm); | |
195 bottom_obj += oop(bottom_obj)->size(); | |
196 assert(bottom_obj <= sp_top, "just checking"); | |
197 } while (bottom_obj < top); | |
198 pm->drain_stacks_cond_depth(); | |
199 } else { | |
200 do { | |
201 oop(bottom_obj)->copy_contents(pm); | |
202 bottom_obj += oop(bottom_obj)->size(); | |
203 assert(bottom_obj <= sp_top, "just checking"); | |
204 } while (bottom_obj < top); | |
205 } | |
206 // remember top oop* scanned | |
207 prev_top = top; | |
208 } | |
209 } | |
210 } | |
211 } | |
212 | |
213 void CardTableExtension::scavenge_contents_parallel(ObjectStartArray* start_array, | |
214 MutableSpace* sp, | |
215 HeapWord* space_top, | |
216 PSPromotionManager* pm, | |
217 uint stripe_number) { | |
218 int ssize = 128; // Naked constant! Work unit = 64k. | |
219 int dirty_card_count = 0; | |
220 bool depth_first = pm->depth_first(); | |
221 | |
222 oop* sp_top = (oop*)space_top; | |
223 jbyte* start_card = byte_for(sp->bottom()); | |
224 jbyte* end_card = byte_for(sp_top - 1) + 1; | |
225 oop* last_scanned = NULL; // Prevent scanning objects more than once | |
226 for (jbyte* slice = start_card; slice < end_card; slice += ssize*ParallelGCThreads) { | |
227 jbyte* worker_start_card = slice + stripe_number * ssize; | |
228 if (worker_start_card >= end_card) | |
229 return; // We're done. | |
230 | |
231 jbyte* worker_end_card = worker_start_card + ssize; | |
232 if (worker_end_card > end_card) | |
233 worker_end_card = end_card; | |
234 | |
235 // We do not want to scan objects more than once. In order to accomplish | |
236 // this, we assert that any object with an object head inside our 'slice' | |
237 // belongs to us. We may need to extend the range of scanned cards if the | |
238 // last object continues into the next 'slice'. | |
239 // | |
240 // Note! ending cards are exclusive! | |
241 HeapWord* slice_start = addr_for(worker_start_card); | |
242 HeapWord* slice_end = MIN2((HeapWord*) sp_top, addr_for(worker_end_card)); | |
243 | |
244 // If there are not objects starting within the chunk, skip it. | |
245 if (!start_array->object_starts_in_range(slice_start, slice_end)) { | |
246 continue; | |
247 } | |
248 // Update our begining addr | |
249 HeapWord* first_object = start_array->object_start(slice_start); | |
250 debug_only(oop* first_object_within_slice = (oop*) first_object;) | |
251 if (first_object < slice_start) { | |
252 last_scanned = (oop*)(first_object + oop(first_object)->size()); | |
253 debug_only(first_object_within_slice = last_scanned;) | |
254 worker_start_card = byte_for(last_scanned); | |
255 } | |
256 | |
257 // Update the ending addr | |
258 if (slice_end < (HeapWord*)sp_top) { | |
259 // The subtraction is important! An object may start precisely at slice_end. | |
260 HeapWord* last_object = start_array->object_start(slice_end - 1); | |
261 slice_end = last_object + oop(last_object)->size(); | |
262 // worker_end_card is exclusive, so bump it one past the end of last_object's | |
263 // covered span. | |
264 worker_end_card = byte_for(slice_end) + 1; | |
265 | |
266 if (worker_end_card > end_card) | |
267 worker_end_card = end_card; | |
268 } | |
269 | |
270 assert(slice_end <= (HeapWord*)sp_top, "Last object in slice crosses space boundary"); | |
271 assert(is_valid_card_address(worker_start_card), "Invalid worker start card"); | |
272 assert(is_valid_card_address(worker_end_card), "Invalid worker end card"); | |
273 // Note that worker_start_card >= worker_end_card is legal, and happens when | |
274 // an object spans an entire slice. | |
275 assert(worker_start_card <= end_card, "worker start card beyond end card"); | |
276 assert(worker_end_card <= end_card, "worker end card beyond end card"); | |
277 | |
278 jbyte* current_card = worker_start_card; | |
279 while (current_card < worker_end_card) { | |
280 // Find an unclean card. | |
281 while (current_card < worker_end_card && card_is_clean(*current_card)) { | |
282 current_card++; | |
283 } | |
284 jbyte* first_unclean_card = current_card; | |
285 | |
286 // Find the end of a run of contiguous unclean cards | |
287 while (current_card < worker_end_card && !card_is_clean(*current_card)) { | |
288 while (current_card < worker_end_card && !card_is_clean(*current_card)) { | |
289 current_card++; | |
290 } | |
291 | |
292 if (current_card < worker_end_card) { | |
293 // Some objects may be large enough to span several cards. If such | |
294 // an object has more than one dirty card, separated by a clean card, | |
295 // we will attempt to scan it twice. The test against "last_scanned" | |
296 // prevents the redundant object scan, but it does not prevent newly | |
297 // marked cards from being cleaned. | |
298 HeapWord* last_object_in_dirty_region = start_array->object_start(addr_for(current_card)-1); | |
299 size_t size_of_last_object = oop(last_object_in_dirty_region)->size(); | |
300 HeapWord* end_of_last_object = last_object_in_dirty_region + size_of_last_object; | |
301 jbyte* ending_card_of_last_object = byte_for(end_of_last_object); | |
302 assert(ending_card_of_last_object <= worker_end_card, "ending_card_of_last_object is greater than worker_end_card"); | |
303 if (ending_card_of_last_object > current_card) { | |
304 // This means the object spans the next complete card. | |
305 // We need to bump the current_card to ending_card_of_last_object | |
306 current_card = ending_card_of_last_object; | |
307 } | |
308 } | |
309 } | |
310 jbyte* following_clean_card = current_card; | |
311 | |
312 if (first_unclean_card < worker_end_card) { | |
313 oop* p = (oop*) start_array->object_start(addr_for(first_unclean_card)); | |
314 assert((HeapWord*)p <= addr_for(first_unclean_card), "checking"); | |
315 // "p" should always be >= "last_scanned" because newly GC dirtied | |
316 // cards are no longer scanned again (see comment at end | |
317 // of loop on the increment of "current_card"). Test that | |
318 // hypothesis before removing this code. | |
319 // If this code is removed, deal with the first time through | |
320 // the loop when the last_scanned is the object starting in | |
321 // the previous slice. | |
322 assert((p >= last_scanned) || | |
323 (last_scanned == first_object_within_slice), | |
324 "Should no longer be possible"); | |
325 if (p < last_scanned) { | |
326 // Avoid scanning more than once; this can happen because | |
327 // newgen cards set by GC may a different set than the | |
328 // originally dirty set | |
329 p = last_scanned; | |
330 } | |
331 oop* to = (oop*)addr_for(following_clean_card); | |
332 | |
333 // Test slice_end first! | |
334 if ((HeapWord*)to > slice_end) { | |
335 to = (oop*)slice_end; | |
336 } else if (to > sp_top) { | |
337 to = sp_top; | |
338 } | |
339 | |
340 // we know which cards to scan, now clear them | |
341 if (first_unclean_card <= worker_start_card+1) | |
342 first_unclean_card = worker_start_card+1; | |
343 if (following_clean_card >= worker_end_card-1) | |
344 following_clean_card = worker_end_card-1; | |
345 | |
346 while (first_unclean_card < following_clean_card) { | |
347 *first_unclean_card++ = clean_card; | |
348 } | |
349 | |
350 const int interval = PrefetchScanIntervalInBytes; | |
351 // scan all objects in the range | |
352 if (interval != 0) { | |
353 // hoisted the if (depth_first) check out of the loop | |
354 if (depth_first) { | |
355 while (p < to) { | |
356 Prefetch::write(p, interval); | |
357 oop m = oop(p); | |
358 assert(m->is_oop_or_null(), "check for header"); | |
359 m->push_contents(pm); | |
360 p += m->size(); | |
361 } | |
362 pm->drain_stacks_cond_depth(); | |
363 } else { | |
364 while (p < to) { | |
365 Prefetch::write(p, interval); | |
366 oop m = oop(p); | |
367 assert(m->is_oop_or_null(), "check for header"); | |
368 m->copy_contents(pm); | |
369 p += m->size(); | |
370 } | |
371 } | |
372 } else { | |
373 // hoisted the if (depth_first) check out of the loop | |
374 if (depth_first) { | |
375 while (p < to) { | |
376 oop m = oop(p); | |
377 assert(m->is_oop_or_null(), "check for header"); | |
378 m->push_contents(pm); | |
379 p += m->size(); | |
380 } | |
381 pm->drain_stacks_cond_depth(); | |
382 } else { | |
383 while (p < to) { | |
384 oop m = oop(p); | |
385 assert(m->is_oop_or_null(), "check for header"); | |
386 m->copy_contents(pm); | |
387 p += m->size(); | |
388 } | |
389 } | |
390 } | |
391 last_scanned = p; | |
392 } | |
393 // "current_card" is still the "following_clean_card" or | |
394 // the current_card is >= the worker_end_card so the | |
395 // loop will not execute again. | |
396 assert((current_card == following_clean_card) || | |
397 (current_card >= worker_end_card), | |
398 "current_card should only be incremented if it still equals " | |
399 "following_clean_card"); | |
400 // Increment current_card so that it is not processed again. | |
401 // It may now be dirty because a old-to-young pointer was | |
402 // found on it an updated. If it is now dirty, it cannot be | |
403 // be safely cleaned in the next iteration. | |
404 current_card++; | |
405 } | |
406 } | |
407 } | |
408 | |
409 // This should be called before a scavenge. | |
410 void CardTableExtension::verify_all_young_refs_imprecise() { | |
411 CheckForUnmarkedObjects check; | |
412 | |
413 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
414 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
415 | |
416 PSOldGen* old_gen = heap->old_gen(); | |
417 PSPermGen* perm_gen = heap->perm_gen(); | |
418 | |
419 old_gen->object_iterate(&check); | |
420 perm_gen->object_iterate(&check); | |
421 } | |
422 | |
423 // This should be called immediately after a scavenge, before mutators resume. | |
424 void CardTableExtension::verify_all_young_refs_precise() { | |
425 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
426 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
427 | |
428 PSOldGen* old_gen = heap->old_gen(); | |
429 PSPermGen* perm_gen = heap->perm_gen(); | |
430 | |
431 CheckForPreciseMarks check(heap->young_gen(), (CardTableExtension*)heap->barrier_set()); | |
432 | |
433 old_gen->oop_iterate(&check); | |
434 perm_gen->oop_iterate(&check); | |
435 | |
436 verify_all_young_refs_precise_helper(old_gen->object_space()->used_region()); | |
437 verify_all_young_refs_precise_helper(perm_gen->object_space()->used_region()); | |
438 } | |
439 | |
440 void CardTableExtension::verify_all_young_refs_precise_helper(MemRegion mr) { | |
441 CardTableExtension* card_table = (CardTableExtension*)Universe::heap()->barrier_set(); | |
442 // FIX ME ASSERT HERE | |
443 | |
444 jbyte* bot = card_table->byte_for(mr.start()); | |
445 jbyte* top = card_table->byte_for(mr.end()); | |
446 while(bot <= top) { | |
447 assert(*bot == clean_card || *bot == verify_card, "Found unwanted or unknown card mark"); | |
448 if (*bot == verify_card) | |
449 *bot = youngergen_card; | |
450 bot++; | |
451 } | |
452 } | |
453 | |
454 bool CardTableExtension::addr_is_marked_imprecise(void *addr) { | |
455 jbyte* p = byte_for(addr); | |
456 jbyte val = *p; | |
457 | |
458 if (card_is_dirty(val)) | |
459 return true; | |
460 | |
461 if (card_is_newgen(val)) | |
462 return true; | |
463 | |
464 if (card_is_clean(val)) | |
465 return false; | |
466 | |
467 assert(false, "Found unhandled card mark type"); | |
468 | |
469 return false; | |
470 } | |
471 | |
472 // Also includes verify_card | |
473 bool CardTableExtension::addr_is_marked_precise(void *addr) { | |
474 jbyte* p = byte_for(addr); | |
475 jbyte val = *p; | |
476 | |
477 if (card_is_newgen(val)) | |
478 return true; | |
479 | |
480 if (card_is_verify(val)) | |
481 return true; | |
482 | |
483 if (card_is_clean(val)) | |
484 return false; | |
485 | |
486 if (card_is_dirty(val)) | |
487 return false; | |
488 | |
489 assert(false, "Found unhandled card mark type"); | |
490 | |
491 return false; | |
492 } | |
493 | |
494 // Assumes that only the base or the end changes. This allows indentification | |
495 // of the region that is being resized. The | |
496 // CardTableModRefBS::resize_covered_region() is used for the normal case | |
497 // where the covered regions are growing or shrinking at the high end. | |
498 // The method resize_covered_region_by_end() is analogous to | |
499 // CardTableModRefBS::resize_covered_region() but | |
500 // for regions that grow or shrink at the low end. | |
501 void CardTableExtension::resize_covered_region(MemRegion new_region) { | |
502 | |
503 for (int i = 0; i < _cur_covered_regions; i++) { | |
504 if (_covered[i].start() == new_region.start()) { | |
505 // Found a covered region with the same start as the | |
506 // new region. The region is growing or shrinking | |
507 // from the start of the region. | |
508 resize_covered_region_by_start(new_region); | |
509 return; | |
510 } | |
511 if (_covered[i].start() > new_region.start()) { | |
512 break; | |
513 } | |
514 } | |
515 | |
516 int changed_region = -1; | |
517 for (int j = 0; j < _cur_covered_regions; j++) { | |
518 if (_covered[j].end() == new_region.end()) { | |
519 changed_region = j; | |
520 // This is a case where the covered region is growing or shrinking | |
521 // at the start of the region. | |
522 assert(changed_region != -1, "Don't expect to add a covered region"); | |
523 assert(_covered[changed_region].byte_size() != new_region.byte_size(), | |
524 "The sizes should be different here"); | |
525 resize_covered_region_by_end(changed_region, new_region); | |
526 return; | |
527 } | |
528 } | |
529 // This should only be a new covered region (where no existing | |
530 // covered region matches at the start or the end). | |
531 assert(_cur_covered_regions < _max_covered_regions, | |
532 "An existing region should have been found"); | |
533 resize_covered_region_by_start(new_region); | |
534 } | |
535 | |
536 void CardTableExtension::resize_covered_region_by_start(MemRegion new_region) { | |
537 CardTableModRefBS::resize_covered_region(new_region); | |
538 debug_only(verify_guard();) | |
539 } | |
540 | |
541 void CardTableExtension::resize_covered_region_by_end(int changed_region, | |
542 MemRegion new_region) { | |
543 assert(SafepointSynchronize::is_at_safepoint(), | |
544 "Only expect an expansion at the low end at a GC"); | |
545 debug_only(verify_guard();) | |
546 #ifdef ASSERT | |
547 for (int k = 0; k < _cur_covered_regions; k++) { | |
548 if (_covered[k].end() == new_region.end()) { | |
549 assert(changed_region == k, "Changed region is incorrect"); | |
550 break; | |
551 } | |
552 } | |
553 #endif | |
554 | |
555 // Commit new or uncommit old pages, if necessary. | |
556 resize_commit_uncommit(changed_region, new_region); | |
557 | |
558 // Update card table entries | |
559 resize_update_card_table_entries(changed_region, new_region); | |
560 | |
561 // Set the new start of the committed region | |
562 resize_update_committed_table(changed_region, new_region); | |
563 | |
564 // Update the covered region | |
565 resize_update_covered_table(changed_region, new_region); | |
566 | |
567 if (TraceCardTableModRefBS) { | |
568 int ind = changed_region; | |
569 gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: "); | |
570 gclog_or_tty->print_cr(" " | |
571 " _covered[%d].start(): " INTPTR_FORMAT | |
572 " _covered[%d].last(): " INTPTR_FORMAT, | |
573 ind, _covered[ind].start(), | |
574 ind, _covered[ind].last()); | |
575 gclog_or_tty->print_cr(" " | |
576 " _committed[%d].start(): " INTPTR_FORMAT | |
577 " _committed[%d].last(): " INTPTR_FORMAT, | |
578 ind, _committed[ind].start(), | |
579 ind, _committed[ind].last()); | |
580 gclog_or_tty->print_cr(" " | |
581 " byte_for(start): " INTPTR_FORMAT | |
582 " byte_for(last): " INTPTR_FORMAT, | |
583 byte_for(_covered[ind].start()), | |
584 byte_for(_covered[ind].last())); | |
585 gclog_or_tty->print_cr(" " | |
586 " addr_for(start): " INTPTR_FORMAT | |
587 " addr_for(last): " INTPTR_FORMAT, | |
588 addr_for((jbyte*) _committed[ind].start()), | |
589 addr_for((jbyte*) _committed[ind].last())); | |
590 } | |
591 debug_only(verify_guard();) | |
592 } | |
593 | |
594 void CardTableExtension::resize_commit_uncommit(int changed_region, | |
595 MemRegion new_region) { | |
596 // Commit new or uncommit old pages, if necessary. | |
597 MemRegion cur_committed = _committed[changed_region]; | |
598 assert(_covered[changed_region].end() == new_region.end(), | |
599 "The ends of the regions are expected to match"); | |
600 // Extend the start of this _committed region to | |
601 // to cover the start of any previous _committed region. | |
602 // This forms overlapping regions, but never interior regions. | |
603 HeapWord* min_prev_start = lowest_prev_committed_start(changed_region); | |
604 if (min_prev_start < cur_committed.start()) { | |
605 // Only really need to set start of "cur_committed" to | |
606 // the new start (min_prev_start) but assertion checking code | |
607 // below use cur_committed.end() so make it correct. | |
608 MemRegion new_committed = | |
609 MemRegion(min_prev_start, cur_committed.end()); | |
610 cur_committed = new_committed; | |
611 } | |
612 #ifdef ASSERT | |
613 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
614 assert(cur_committed.start() == | |
615 (HeapWord*) align_size_up((uintptr_t) cur_committed.start(), | |
616 os::vm_page_size()), | |
617 "Starts should have proper alignment"); | |
618 #endif | |
619 | |
620 jbyte* new_start = byte_for(new_region.start()); | |
621 // Round down because this is for the start address | |
622 HeapWord* new_start_aligned = | |
623 (HeapWord*)align_size_down((uintptr_t)new_start, os::vm_page_size()); | |
624 // The guard page is always committed and should not be committed over. | |
625 // This method is used in cases where the generation is growing toward | |
626 // lower addresses but the guard region is still at the end of the | |
627 // card table. That still makes sense when looking for writes | |
628 // off the end of the card table. | |
629 if (new_start_aligned < cur_committed.start()) { | |
630 // Expand the committed region | |
631 // | |
632 // Case A | |
633 // |+ guard +| | |
634 // |+ cur committed +++++++++| | |
635 // |+ new committed +++++++++++++++++| | |
636 // | |
637 // Case B | |
638 // |+ guard +| | |
639 // |+ cur committed +| | |
640 // |+ new committed +++++++| | |
641 // | |
642 // These are not expected because the calculation of the | |
643 // cur committed region and the new committed region | |
644 // share the same end for the covered region. | |
645 // Case C | |
646 // |+ guard +| | |
647 // |+ cur committed +| | |
648 // |+ new committed +++++++++++++++++| | |
649 // Case D | |
650 // |+ guard +| | |
651 // |+ cur committed +++++++++++| | |
652 // |+ new committed +++++++| | |
653 | |
654 HeapWord* new_end_for_commit = | |
655 MIN2(cur_committed.end(), _guard_region.start()); | |
656 MemRegion new_committed = | |
657 MemRegion(new_start_aligned, new_end_for_commit); | |
658 if(!new_committed.is_empty()) { | |
659 if (!os::commit_memory((char*)new_committed.start(), | |
660 new_committed.byte_size())) { | |
661 vm_exit_out_of_memory(new_committed.byte_size(), | |
662 "card table expansion"); | |
663 } | |
664 } | |
665 } else if (new_start_aligned > cur_committed.start()) { | |
666 // Shrink the committed region | |
667 MemRegion uncommit_region = committed_unique_to_self(changed_region, | |
668 MemRegion(cur_committed.start(), new_start_aligned)); | |
669 if (!uncommit_region.is_empty()) { | |
670 if (!os::uncommit_memory((char*)uncommit_region.start(), | |
671 uncommit_region.byte_size())) { | |
672 vm_exit_out_of_memory(uncommit_region.byte_size(), | |
673 "card table contraction"); | |
674 } | |
675 } | |
676 } | |
677 assert(_committed[changed_region].end() == cur_committed.end(), | |
678 "end should not change"); | |
679 } | |
680 | |
681 void CardTableExtension::resize_update_committed_table(int changed_region, | |
682 MemRegion new_region) { | |
683 | |
684 jbyte* new_start = byte_for(new_region.start()); | |
685 // Set the new start of the committed region | |
686 HeapWord* new_start_aligned = | |
687 (HeapWord*)align_size_down((uintptr_t)new_start, | |
688 os::vm_page_size()); | |
689 MemRegion new_committed = MemRegion(new_start_aligned, | |
690 _committed[changed_region].end()); | |
691 _committed[changed_region] = new_committed; | |
692 _committed[changed_region].set_start(new_start_aligned); | |
693 } | |
694 | |
695 void CardTableExtension::resize_update_card_table_entries(int changed_region, | |
696 MemRegion new_region) { | |
697 debug_only(verify_guard();) | |
698 MemRegion original_covered = _covered[changed_region]; | |
699 // Initialize the card entries. Only consider the | |
700 // region covered by the card table (_whole_heap) | |
701 jbyte* entry; | |
702 if (new_region.start() < _whole_heap.start()) { | |
703 entry = byte_for(_whole_heap.start()); | |
704 } else { | |
705 entry = byte_for(new_region.start()); | |
706 } | |
707 jbyte* end = byte_for(original_covered.start()); | |
708 // If _whole_heap starts at the original covered regions start, | |
709 // this loop will not execute. | |
710 while (entry < end) { *entry++ = clean_card; } | |
711 } | |
712 | |
713 void CardTableExtension::resize_update_covered_table(int changed_region, | |
714 MemRegion new_region) { | |
715 // Update the covered region | |
716 _covered[changed_region].set_start(new_region.start()); | |
717 _covered[changed_region].set_word_size(new_region.word_size()); | |
718 | |
719 // reorder regions. There should only be at most 1 out | |
720 // of order. | |
721 for (int i = _cur_covered_regions-1 ; i > 0; i--) { | |
722 if (_covered[i].start() < _covered[i-1].start()) { | |
723 MemRegion covered_mr = _covered[i-1]; | |
724 _covered[i-1] = _covered[i]; | |
725 _covered[i] = covered_mr; | |
726 MemRegion committed_mr = _committed[i-1]; | |
727 _committed[i-1] = _committed[i]; | |
728 _committed[i] = committed_mr; | |
729 break; | |
730 } | |
731 } | |
732 #ifdef ASSERT | |
733 for (int m = 0; m < _cur_covered_regions-1; m++) { | |
734 assert(_covered[m].start() <= _covered[m+1].start(), | |
735 "Covered regions out of order"); | |
736 assert(_committed[m].start() <= _committed[m+1].start(), | |
737 "Committed regions out of order"); | |
738 } | |
739 #endif | |
740 } | |
741 | |
742 // Returns the start of any committed region that is lower than | |
743 // the target committed region (index ind) and that intersects the | |
744 // target region. If none, return start of target region. | |
745 // | |
746 // ------------- | |
747 // | | | |
748 // ------------- | |
749 // ------------ | |
750 // | target | | |
751 // ------------ | |
752 // ------------- | |
753 // | | | |
754 // ------------- | |
755 // ^ returns this | |
756 // | |
757 // ------------- | |
758 // | | | |
759 // ------------- | |
760 // ------------ | |
761 // | target | | |
762 // ------------ | |
763 // ------------- | |
764 // | | | |
765 // ------------- | |
766 // ^ returns this | |
767 | |
768 HeapWord* CardTableExtension::lowest_prev_committed_start(int ind) const { | |
769 assert(_cur_covered_regions >= 0, "Expecting at least on region"); | |
770 HeapWord* min_start = _committed[ind].start(); | |
771 for (int j = 0; j < ind; j++) { | |
772 HeapWord* this_start = _committed[j].start(); | |
773 if ((this_start < min_start) && | |
774 !(_committed[j].intersection(_committed[ind])).is_empty()) { | |
775 min_start = this_start; | |
776 } | |
777 } | |
778 return min_start; | |
779 } |