1 /*
2 * Copyright (c) 2018, 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 #include "precompiled.hpp"
25
26 #include "logging/log.hpp"
27 #include "logging/logStream.hpp"
28 #include "memory/binaryTreeDictionary.inline.hpp"
29 #include "memory/freeList.inline.hpp"
30 #include "memory/metaspace/chunkManager.hpp"
31 #include "memory/metaspace/metachunk.hpp"
32 #include "memory/metaspace/metaspaceCommon.hpp"
33 #include "memory/metaspace/metaspaceStatistics.hpp"
34 #include "memory/metaspace/occupancyMap.hpp"
35 #include "memory/metaspace/virtualSpaceNode.hpp"
36 #include "runtime/mutexLocker.hpp"
37 #include "utilities/debug.hpp"
38 #include "utilities/globalDefinitions.hpp"
39 #include "utilities/ostream.hpp"
40
41 namespace metaspace {
42
43 ChunkManager::ChunkManager(bool is_class)
44 : _is_class(is_class), _free_chunks_total(0), _free_chunks_count(0) {
45 _free_chunks[SpecializedIndex].set_size(get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class));
46 _free_chunks[SmallIndex].set_size(get_size_for_nonhumongous_chunktype(SmallIndex, is_class));
47 _free_chunks[MediumIndex].set_size(get_size_for_nonhumongous_chunktype(MediumIndex, is_class));
48 }
49
50 void ChunkManager::remove_chunk(Metachunk* chunk) {
51 size_t word_size = chunk->word_size();
52 ChunkIndex index = list_index(word_size);
53 if (index != HumongousIndex) {
54 free_chunks(index)->remove_chunk(chunk);
55 } else {
56 humongous_dictionary()->remove_chunk(chunk);
57 }
58
59 // Chunk has been removed from the chunks free list, update counters.
60 account_for_removed_chunk(chunk);
61 }
62
63 bool ChunkManager::attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type) {
64 assert_lock_strong(MetaspaceExpand_lock);
65 assert(chunk != NULL, "invalid chunk pointer");
66 // Check for valid merge combinations.
67 assert((chunk->get_chunk_type() == SpecializedIndex &&
68 (target_chunk_type == SmallIndex || target_chunk_type == MediumIndex)) ||
69 (chunk->get_chunk_type() == SmallIndex && target_chunk_type == MediumIndex),
70 "Invalid chunk merge combination.");
71
72 const size_t target_chunk_word_size =
73 get_size_for_nonhumongous_chunktype(target_chunk_type, this->is_class());
74
75 // [ prospective merge region )
76 MetaWord* const p_merge_region_start =
77 (MetaWord*) align_down(chunk, target_chunk_word_size * sizeof(MetaWord));
78 MetaWord* const p_merge_region_end =
79 p_merge_region_start + target_chunk_word_size;
80
81 // We need the VirtualSpaceNode containing this chunk and its occupancy map.
82 VirtualSpaceNode* const vsn = chunk->container();
83 OccupancyMap* const ocmap = vsn->occupancy_map();
84
85 // The prospective chunk merge range must be completely contained by the
86 // committed range of the virtual space node.
87 if (p_merge_region_start < vsn->bottom() || p_merge_region_end > vsn->top()) {
88 return false;
89 }
90
91 // Only attempt to merge this range if at its start a chunk starts and at its end
92 // a chunk ends. If a chunk (can only be humongous) straddles either start or end
93 // of that range, we cannot merge.
94 if (!ocmap->chunk_starts_at_address(p_merge_region_start)) {
95 return false;
96 }
97 if (p_merge_region_end < vsn->top() &&
98 !ocmap->chunk_starts_at_address(p_merge_region_end)) {
99 return false;
100 }
101
102 // Now check if the prospective merge area contains live chunks. If it does we cannot merge.
103 if (ocmap->is_region_in_use(p_merge_region_start, target_chunk_word_size)) {
104 return false;
105 }
106
107 // Success! Remove all chunks in this region...
108 log_trace(gc, metaspace, freelist)("%s: coalescing chunks in area [%p-%p)...",
109 (is_class() ? "class space" : "metaspace"),
110 p_merge_region_start, p_merge_region_end);
111
112 const int num_chunks_removed =
113 remove_chunks_in_area(p_merge_region_start, target_chunk_word_size);
114
115 // ... and create a single new bigger chunk.
116 Metachunk* const p_new_chunk =
117 ::new (p_merge_region_start) Metachunk(target_chunk_type, is_class(), target_chunk_word_size, vsn);
118 assert(p_new_chunk == (Metachunk*)p_merge_region_start, "Sanity");
119 p_new_chunk->set_origin(origin_merge);
120
121 log_trace(gc, metaspace, freelist)("%s: created coalesced chunk at %p, size " SIZE_FORMAT_HEX ".",
122 (is_class() ? "class space" : "metaspace"),
123 p_new_chunk, p_new_chunk->word_size() * sizeof(MetaWord));
124
125 // Fix occupancy map: remove old start bits of the small chunks and set new start bit.
126 ocmap->wipe_chunk_start_bits_in_region(p_merge_region_start, target_chunk_word_size);
127 ocmap->set_chunk_starts_at_address(p_merge_region_start, true);
128
129 // Mark chunk as free. Note: it is not necessary to update the occupancy
130 // map in-use map, because the old chunks were also free, so nothing
131 // should have changed.
132 p_new_chunk->set_is_tagged_free(true);
133
134 // Add new chunk to its freelist.
135 ChunkList* const list = free_chunks(target_chunk_type);
136 list->return_chunk_at_head(p_new_chunk);
137
138 // And adjust ChunkManager:: _free_chunks_count (_free_chunks_total
139 // should not have changed, because the size of the space should be the same)
140 _free_chunks_count -= num_chunks_removed;
141 _free_chunks_count ++;
142
143 // VirtualSpaceNode::container_count does not have to be modified:
144 // it means "number of active (non-free) chunks", so merging free chunks
145 // should not affect that count.
146
147 // At the end of a chunk merge, run verification tests.
148 if (VerifyMetaspace) {
149 DEBUG_ONLY(this->locked_verify());
150 DEBUG_ONLY(vsn->verify());
151 }
152
153 return true;
154 }
155
156 // Remove all chunks in the given area - the chunks are supposed to be free -
157 // from their corresponding freelists. Mark them as invalid.
158 // - This does not correct the occupancy map.
159 // - This does not adjust the counters in ChunkManager.
160 // - Does not adjust container count counter in containing VirtualSpaceNode
161 // Returns number of chunks removed.
162 int ChunkManager::remove_chunks_in_area(MetaWord* p, size_t word_size) {
163 assert(p != NULL && word_size > 0, "Invalid range.");
164 const size_t smallest_chunk_size = get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class());
165 assert_is_aligned(word_size, smallest_chunk_size);
166
167 Metachunk* const start = (Metachunk*) p;
168 const Metachunk* const end = (Metachunk*)(p + word_size);
169 Metachunk* cur = start;
170 int num_removed = 0;
171 while (cur < end) {
172 Metachunk* next = (Metachunk*)(((MetaWord*)cur) + cur->word_size());
173 DEBUG_ONLY(do_verify_chunk(cur));
174 assert(cur->get_chunk_type() != HumongousIndex, "Unexpected humongous chunk found at %p.", cur);
175 assert(cur->is_tagged_free(), "Chunk expected to be free (%p)", cur);
176 log_trace(gc, metaspace, freelist)("%s: removing chunk %p, size " SIZE_FORMAT_HEX ".",
177 (is_class() ? "class space" : "metaspace"),
178 cur, cur->word_size() * sizeof(MetaWord));
179 cur->remove_sentinel();
180 // Note: cannot call ChunkManager::remove_chunk, because that
181 // modifies the counters in ChunkManager, which we do not want. So
182 // we call remove_chunk on the freelist directly (see also the
183 // splitting function which does the same).
184 ChunkList* const list = free_chunks(list_index(cur->word_size()));
185 list->remove_chunk(cur);
186 num_removed ++;
187 cur = next;
188 }
189 return num_removed;
190 }
191
192 size_t ChunkManager::free_chunks_total_words() {
193 return _free_chunks_total;
194 }
195
196 size_t ChunkManager::free_chunks_total_bytes() {
197 return free_chunks_total_words() * BytesPerWord;
198 }
199
200 // Update internal accounting after a chunk was added
201 void ChunkManager::account_for_added_chunk(const Metachunk* c) {
202 assert_lock_strong(MetaspaceExpand_lock);
203 _free_chunks_count ++;
204 _free_chunks_total += c->word_size();
205 }
206
207 // Update internal accounting after a chunk was removed
208 void ChunkManager::account_for_removed_chunk(const Metachunk* c) {
209 assert_lock_strong(MetaspaceExpand_lock);
210 assert(_free_chunks_count >= 1,
211 "ChunkManager::_free_chunks_count: about to go negative (" SIZE_FORMAT ").", _free_chunks_count);
212 assert(_free_chunks_total >= c->word_size(),
213 "ChunkManager::_free_chunks_total: about to go negative"
214 "(now: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ").", _free_chunks_total, c->word_size());
215 _free_chunks_count --;
216 _free_chunks_total -= c->word_size();
217 }
218
219 size_t ChunkManager::free_chunks_count() {
220 #ifdef ASSERT
221 if (!UseConcMarkSweepGC && !MetaspaceExpand_lock->is_locked()) {
222 MutexLockerEx cl(MetaspaceExpand_lock,
223 Mutex::_no_safepoint_check_flag);
224 // This lock is only needed in debug because the verification
225 // of the _free_chunks_totals walks the list of free chunks
226 slow_locked_verify_free_chunks_count();
227 }
228 #endif
229 return _free_chunks_count;
230 }
231
232 ChunkIndex ChunkManager::list_index(size_t size) {
233 return get_chunk_type_by_size(size, is_class());
234 }
235
236 size_t ChunkManager::size_by_index(ChunkIndex index) const {
237 index_bounds_check(index);
238 assert(index != HumongousIndex, "Do not call for humongous chunks.");
239 return get_size_for_nonhumongous_chunktype(index, is_class());
240 }
241
242 void ChunkManager::locked_verify_free_chunks_total() {
243 assert_lock_strong(MetaspaceExpand_lock);
244 assert(sum_free_chunks() == _free_chunks_total,
245 "_free_chunks_total " SIZE_FORMAT " is not the"
246 " same as sum " SIZE_FORMAT, _free_chunks_total,
247 sum_free_chunks());
248 }
249
250 void ChunkManager::locked_verify_free_chunks_count() {
251 assert_lock_strong(MetaspaceExpand_lock);
252 assert(sum_free_chunks_count() == _free_chunks_count,
253 "_free_chunks_count " SIZE_FORMAT " is not the"
254 " same as sum " SIZE_FORMAT, _free_chunks_count,
255 sum_free_chunks_count());
256 }
257
258 void ChunkManager::verify() {
259 MutexLockerEx cl(MetaspaceExpand_lock,
260 Mutex::_no_safepoint_check_flag);
261 locked_verify();
262 }
263
264 void ChunkManager::locked_verify() {
265 locked_verify_free_chunks_count();
266 locked_verify_free_chunks_total();
267 for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
268 ChunkList* list = free_chunks(i);
269 if (list != NULL) {
270 Metachunk* chunk = list->head();
271 while (chunk) {
272 DEBUG_ONLY(do_verify_chunk(chunk);)
273 assert(chunk->is_tagged_free(), "Chunk should be tagged as free.");
274 chunk = chunk->next();
275 }
276 }
277 }
278 }
279
280 void ChunkManager::locked_print_free_chunks(outputStream* st) {
281 assert_lock_strong(MetaspaceExpand_lock);
282 st->print_cr("Free chunk total " SIZE_FORMAT " count " SIZE_FORMAT,
283 _free_chunks_total, _free_chunks_count);
284 }
285
286 void ChunkManager::locked_print_sum_free_chunks(outputStream* st) {
287 assert_lock_strong(MetaspaceExpand_lock);
288 st->print_cr("Sum free chunk total " SIZE_FORMAT " count " SIZE_FORMAT,
289 sum_free_chunks(), sum_free_chunks_count());
290 }
291
292 ChunkList* ChunkManager::free_chunks(ChunkIndex index) {
293 assert(index == SpecializedIndex || index == SmallIndex || index == MediumIndex,
294 "Bad index: %d", (int)index);
295
296 return &_free_chunks[index];
297 }
298
299 // These methods that sum the free chunk lists are used in printing
300 // methods that are used in product builds.
301 size_t ChunkManager::sum_free_chunks() {
302 assert_lock_strong(MetaspaceExpand_lock);
303 size_t result = 0;
304 for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
305 ChunkList* list = free_chunks(i);
306
307 if (list == NULL) {
308 continue;
309 }
310
311 result = result + list->count() * list->size();
312 }
313 result = result + humongous_dictionary()->total_size();
314 return result;
315 }
316
317 size_t ChunkManager::sum_free_chunks_count() {
318 assert_lock_strong(MetaspaceExpand_lock);
319 size_t count = 0;
320 for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
321 ChunkList* list = free_chunks(i);
322 if (list == NULL) {
323 continue;
324 }
325 count = count + list->count();
326 }
327 count = count + humongous_dictionary()->total_free_blocks();
328 return count;
329 }
330
331 ChunkList* ChunkManager::find_free_chunks_list(size_t word_size) {
332 ChunkIndex index = list_index(word_size);
333 assert(index < HumongousIndex, "No humongous list");
334 return free_chunks(index);
335 }
336
337 // Helper for chunk splitting: given a target chunk size and a larger free chunk,
338 // split up the larger chunk into n smaller chunks, at least one of which should be
339 // the target chunk of target chunk size. The smaller chunks, including the target
340 // chunk, are returned to the freelist. The pointer to the target chunk is returned.
341 // Note that this chunk is supposed to be removed from the freelist right away.
342 Metachunk* ChunkManager::split_chunk(size_t target_chunk_word_size, Metachunk* larger_chunk) {
343 assert(larger_chunk->word_size() > target_chunk_word_size, "Sanity");
344
345 const ChunkIndex larger_chunk_index = larger_chunk->get_chunk_type();
346 const ChunkIndex target_chunk_index = get_chunk_type_by_size(target_chunk_word_size, is_class());
347
348 MetaWord* const region_start = (MetaWord*)larger_chunk;
349 const size_t region_word_len = larger_chunk->word_size();
350 MetaWord* const region_end = region_start + region_word_len;
351 VirtualSpaceNode* const vsn = larger_chunk->container();
352 OccupancyMap* const ocmap = vsn->occupancy_map();
353
354 // Any larger non-humongous chunk size is a multiple of any smaller chunk size.
355 // Since non-humongous chunks are aligned to their chunk size, the larger chunk should start
356 // at an address suitable to place the smaller target chunk.
357 assert_is_aligned(region_start, target_chunk_word_size);
358
359 // Remove old chunk.
360 free_chunks(larger_chunk_index)->remove_chunk(larger_chunk);
361 larger_chunk->remove_sentinel();
362
363 // Prevent access to the old chunk from here on.
364 larger_chunk = NULL;
365 // ... and wipe it.
366 DEBUG_ONLY(memset(region_start, 0xfe, region_word_len * BytesPerWord));
367
368 // In its place create first the target chunk...
369 MetaWord* p = region_start;
370 Metachunk* target_chunk = ::new (p) Metachunk(target_chunk_index, is_class(), target_chunk_word_size, vsn);
371 assert(target_chunk == (Metachunk*)p, "Sanity");
372 target_chunk->set_origin(origin_split);
373
374 // Note: we do not need to mark its start in the occupancy map
375 // because it coincides with the old chunk start.
376
377 // Mark chunk as free and return to the freelist.
378 do_update_in_use_info_for_chunk(target_chunk, false);
379 free_chunks(target_chunk_index)->return_chunk_at_head(target_chunk);
380
381 // This chunk should now be valid and can be verified.
382 DEBUG_ONLY(do_verify_chunk(target_chunk));
383
384 // In the remaining space create the remainder chunks.
385 p += target_chunk->word_size();
386 assert(p < region_end, "Sanity");
387
388 while (p < region_end) {
389
390 // Find the largest chunk size which fits the alignment requirements at address p.
391 ChunkIndex this_chunk_index = prev_chunk_index(larger_chunk_index);
392 size_t this_chunk_word_size = 0;
393 for(;;) {
394 this_chunk_word_size = get_size_for_nonhumongous_chunktype(this_chunk_index, is_class());
395 if (is_aligned(p, this_chunk_word_size * BytesPerWord)) {
396 break;
397 } else {
398 this_chunk_index = prev_chunk_index(this_chunk_index);
399 assert(this_chunk_index >= target_chunk_index, "Sanity");
400 }
401 }
402
403 assert(this_chunk_word_size >= target_chunk_word_size, "Sanity");
404 assert(is_aligned(p, this_chunk_word_size * BytesPerWord), "Sanity");
405 assert(p + this_chunk_word_size <= region_end, "Sanity");
406
407 // Create splitting chunk.
408 Metachunk* this_chunk = ::new (p) Metachunk(this_chunk_index, is_class(), this_chunk_word_size, vsn);
409 assert(this_chunk == (Metachunk*)p, "Sanity");
410 this_chunk->set_origin(origin_split);
411 ocmap->set_chunk_starts_at_address(p, true);
412 do_update_in_use_info_for_chunk(this_chunk, false);
413
414 // This chunk should be valid and can be verified.
415 DEBUG_ONLY(do_verify_chunk(this_chunk));
416
417 // Return this chunk to freelist and correct counter.
418 free_chunks(this_chunk_index)->return_chunk_at_head(this_chunk);
419 _free_chunks_count ++;
420
421 log_trace(gc, metaspace, freelist)("Created chunk at " PTR_FORMAT ", word size "
422 SIZE_FORMAT_HEX " (%s), in split region [" PTR_FORMAT "..." PTR_FORMAT ").",
423 p2i(this_chunk), this_chunk->word_size(), chunk_size_name(this_chunk_index),
424 p2i(region_start), p2i(region_end));
425
426 p += this_chunk_word_size;
427
428 }
429
430 return target_chunk;
431 }
432
433 Metachunk* ChunkManager::free_chunks_get(size_t word_size) {
434 assert_lock_strong(MetaspaceExpand_lock);
435
436 slow_locked_verify();
437
438 Metachunk* chunk = NULL;
439 bool we_did_split_a_chunk = false;
440
441 if (list_index(word_size) != HumongousIndex) {
442
443 ChunkList* free_list = find_free_chunks_list(word_size);
444 assert(free_list != NULL, "Sanity check");
445
446 chunk = free_list->head();
447
448 if (chunk == NULL) {
449 // Split large chunks into smaller chunks if there are no smaller chunks, just large chunks.
450 // This is the counterpart of the coalescing-upon-chunk-return.
451
452 ChunkIndex target_chunk_index = get_chunk_type_by_size(word_size, is_class());
453
454 // Is there a larger chunk we could split?
455 Metachunk* larger_chunk = NULL;
456 ChunkIndex larger_chunk_index = next_chunk_index(target_chunk_index);
457 while (larger_chunk == NULL && larger_chunk_index < NumberOfFreeLists) {
458 larger_chunk = free_chunks(larger_chunk_index)->head();
459 if (larger_chunk == NULL) {
460 larger_chunk_index = next_chunk_index(larger_chunk_index);
461 }
462 }
463
464 if (larger_chunk != NULL) {
465 assert(larger_chunk->word_size() > word_size, "Sanity");
466 assert(larger_chunk->get_chunk_type() == larger_chunk_index, "Sanity");
467
468 // We found a larger chunk. Lets split it up:
469 // - remove old chunk
470 // - in its place, create new smaller chunks, with at least one chunk
471 // being of target size, the others sized as large as possible. This
472 // is to make sure the resulting chunks are "as coalesced as possible"
473 // (similar to VirtualSpaceNode::retire()).
474 // Note: during this operation both ChunkManager and VirtualSpaceNode
475 // are temporarily invalid, so be careful with asserts.
476
477 log_trace(gc, metaspace, freelist)("%s: splitting chunk " PTR_FORMAT
478 ", word size " SIZE_FORMAT_HEX " (%s), to get a chunk of word size " SIZE_FORMAT_HEX " (%s)...",
479 (is_class() ? "class space" : "metaspace"), p2i(larger_chunk), larger_chunk->word_size(),
480 chunk_size_name(larger_chunk_index), word_size, chunk_size_name(target_chunk_index));
481
482 chunk = split_chunk(word_size, larger_chunk);
483
484 // This should have worked.
485 assert(chunk != NULL, "Sanity");
486 assert(chunk->word_size() == word_size, "Sanity");
487 assert(chunk->is_tagged_free(), "Sanity");
488
489 we_did_split_a_chunk = true;
490
491 }
492 }
493
494 if (chunk == NULL) {
495 return NULL;
496 }
497
498 // Remove the chunk as the head of the list.
499 free_list->remove_chunk(chunk);
500
501 log_trace(gc, metaspace, freelist)("ChunkManager::free_chunks_get: free_list: " PTR_FORMAT " chunks left: " SSIZE_FORMAT ".",
502 p2i(free_list), free_list->count());
503
504 } else {
505 chunk = humongous_dictionary()->get_chunk(word_size);
506
507 if (chunk == NULL) {
508 return NULL;
509 }
510
511 log_trace(gc, metaspace, alloc)("Free list allocate humongous chunk size " SIZE_FORMAT " for requested size " SIZE_FORMAT " waste " SIZE_FORMAT,
512 chunk->word_size(), word_size, chunk->word_size() - word_size);
513 }
514
515 // Chunk has been removed from the chunk manager; update counters.
516 account_for_removed_chunk(chunk);
517 do_update_in_use_info_for_chunk(chunk, true);
518 chunk->container()->inc_container_count();
519 chunk->inc_use_count();
520
521 // Remove it from the links to this freelist
522 chunk->set_next(NULL);
523 chunk->set_prev(NULL);
524
525 // Run some verifications (some more if we did a chunk split)
526 #ifdef ASSERT
527 if (VerifyMetaspace) {
528 locked_verify();
529 VirtualSpaceNode* const vsn = chunk->container();
530 vsn->verify();
531 if (we_did_split_a_chunk) {
532 vsn->verify_free_chunks_are_ideally_merged();
533 }
534 }
535 #endif
536
537 return chunk;
538 }
539
540 Metachunk* ChunkManager::chunk_freelist_allocate(size_t word_size) {
541 assert_lock_strong(MetaspaceExpand_lock);
542 slow_locked_verify();
543
544 // Take from the beginning of the list
545 Metachunk* chunk = free_chunks_get(word_size);
546 if (chunk == NULL) {
547 return NULL;
548 }
549
550 assert((word_size <= chunk->word_size()) ||
551 (list_index(chunk->word_size()) == HumongousIndex),
552 "Non-humongous variable sized chunk");
553 LogTarget(Trace, gc, metaspace, freelist) lt;
554 if (lt.is_enabled()) {
555 size_t list_count;
556 if (list_index(word_size) < HumongousIndex) {
557 ChunkList* list = find_free_chunks_list(word_size);
558 list_count = list->count();
559 } else {
560 list_count = humongous_dictionary()->total_count();
561 }
562 LogStream ls(lt);
563 ls.print("ChunkManager::chunk_freelist_allocate: " PTR_FORMAT " chunk " PTR_FORMAT " size " SIZE_FORMAT " count " SIZE_FORMAT " ",
564 p2i(this), p2i(chunk), chunk->word_size(), list_count);
565 ResourceMark rm;
566 locked_print_free_chunks(&ls);
567 }
568
569 return chunk;
570 }
571
572 void ChunkManager::return_single_chunk(Metachunk* chunk) {
573 const ChunkIndex index = chunk->get_chunk_type();
574 assert_lock_strong(MetaspaceExpand_lock);
575 DEBUG_ONLY(do_verify_chunk(chunk);)
576 assert(chunk != NULL, "Expected chunk.");
577 assert(chunk->container() != NULL, "Container should have been set.");
578 assert(chunk->is_tagged_free() == false, "Chunk should be in use.");
579 index_bounds_check(index);
580
581 // Note: mangle *before* returning the chunk to the freelist or dictionary. It does not
582 // matter for the freelist (non-humongous chunks), but the humongous chunk dictionary
583 // keeps tree node pointers in the chunk payload area which mangle will overwrite.
584 DEBUG_ONLY(chunk->mangle(badMetaWordVal);)
585
586 if (index != HumongousIndex) {
587 // Return non-humongous chunk to freelist.
588 ChunkList* list = free_chunks(index);
589 assert(list->size() == chunk->word_size(), "Wrong chunk type.");
590 list->return_chunk_at_head(chunk);
591 log_trace(gc, metaspace, freelist)("returned one %s chunk at " PTR_FORMAT " to freelist.",
592 chunk_size_name(index), p2i(chunk));
593 } else {
594 // Return humongous chunk to dictionary.
595 assert(chunk->word_size() > free_chunks(MediumIndex)->size(), "Wrong chunk type.");
596 assert(chunk->word_size() % free_chunks(SpecializedIndex)->size() == 0,
597 "Humongous chunk has wrong alignment.");
598 _humongous_dictionary.return_chunk(chunk);
599 log_trace(gc, metaspace, freelist)("returned one %s chunk at " PTR_FORMAT " (word size " SIZE_FORMAT ") to freelist.",
600 chunk_size_name(index), p2i(chunk), chunk->word_size());
601 }
602 chunk->container()->dec_container_count();
603 do_update_in_use_info_for_chunk(chunk, false);
604
605 // Chunk has been added; update counters.
606 account_for_added_chunk(chunk);
607
608 // Attempt coalesce returned chunks with its neighboring chunks:
609 // if this chunk is small or special, attempt to coalesce to a medium chunk.
610 if (index == SmallIndex || index == SpecializedIndex) {
611 if (!attempt_to_coalesce_around_chunk(chunk, MediumIndex)) {
612 // This did not work. But if this chunk is special, we still may form a small chunk?
613 if (index == SpecializedIndex) {
614 if (!attempt_to_coalesce_around_chunk(chunk, SmallIndex)) {
615 // give up.
616 }
617 }
618 }
619 }
620
621 }
622
623 void ChunkManager::return_chunk_list(Metachunk* chunks) {
624 if (chunks == NULL) {
625 return;
626 }
627 LogTarget(Trace, gc, metaspace, freelist) log;
628 if (log.is_enabled()) { // tracing
629 log.print("returning list of chunks...");
630 }
631 unsigned num_chunks_returned = 0;
632 size_t size_chunks_returned = 0;
633 Metachunk* cur = chunks;
634 while (cur != NULL) {
635 // Capture the next link before it is changed
636 // by the call to return_chunk_at_head();
637 Metachunk* next = cur->next();
638 if (log.is_enabled()) { // tracing
639 num_chunks_returned ++;
640 size_chunks_returned += cur->word_size();
641 }
642 return_single_chunk(cur);
643 cur = next;
644 }
645 if (log.is_enabled()) { // tracing
646 log.print("returned %u chunks to freelist, total word size " SIZE_FORMAT ".",
647 num_chunks_returned, size_chunks_returned);
648 }
649 }
650
651 void ChunkManager::collect_statistics(ChunkManagerStatistics* out) const {
652 MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
653 for (ChunkIndex i = ZeroIndex; i < NumberOfInUseLists; i = next_chunk_index(i)) {
654 out->chunk_stats(i).add(num_free_chunks(i), size_free_chunks_in_bytes(i) / sizeof(MetaWord));
655 }
656 }
657
658 } // namespace metaspace
659
660
661