1 /*
2 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2020 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "logging/log.hpp"
28 #include "logging/logStream.hpp"
29 #include "memory/metaspace/chunkManager.hpp"
30 #include "memory/metaspace/counters.hpp"
31 #include "memory/metaspace/freeBlocks.hpp"
32 #include "memory/metaspace/internalStats.hpp"
33 #include "memory/metaspace/metachunk.hpp"
34 #include "memory/metaspace/metaspaceAlignment.hpp"
35 #include "memory/metaspace/metaspaceArena.hpp"
36 #include "memory/metaspace/metaspaceArenaGrowthPolicy.hpp"
37 #include "memory/metaspace/metaspaceCommon.hpp"
38 #include "memory/metaspace/metaspaceSettings.hpp"
39 #include "memory/metaspace/metaspaceStatistics.hpp"
40 #include "memory/metaspace/virtualSpaceList.hpp"
41 #include "runtime/atomic.hpp"
42 #include "runtime/init.hpp"
43 #include "runtime/mutexLocker.hpp"
44 #include "services/memoryService.hpp"
45 #include "utilities/align.hpp"
46 #include "utilities/debug.hpp"
47 #include "utilities/globalDefinitions.hpp"
48
49 namespace metaspace {
50
51 #define LOGFMT "Arena @" PTR_FORMAT " (%s)"
52 #define LOGFMT_ARGS p2i(this), this->_name
53
54 // Returns the level of the next chunk to be added, acc to growth policy.
55 chunklevel_t MetaspaceArena::next_chunk_level() const {
56 const int growth_step = _chunks.count();
57 return _growth_policy->get_level_at_step(growth_step);
58 }
59
60 // Given a chunk, add its remaining free committed space to the free block list.
61 void MetaspaceArena::salvage_chunk(Metachunk* c) {
62 assert_lock_strong(lock());
63 size_t remaining_words = c->free_below_committed_words();
64 if (remaining_words > FreeBlocks::MinWordSize) {
65
66 UL2(trace, "salvaging chunk " METACHUNK_FULL_FORMAT ".", METACHUNK_FULL_FORMAT_ARGS(c));
67
68 MetaWord* ptr = c->allocate(remaining_words);
69 assert(ptr != NULL, "Should have worked");
70 _total_used_words_counter->increment_by(remaining_words);
71
72 add_allocation_to_fbl(ptr, remaining_words);
73
74 // After this operation: the chunk should have no free committed space left.
75 assert(c->free_below_committed_words() == 0,
76 "Salvaging chunk failed (chunk " METACHUNK_FULL_FORMAT ").",
77 METACHUNK_FULL_FORMAT_ARGS(c));
78 }
79 }
80
81 // Allocate a new chunk from the underlying chunk manager able to hold at least
82 // requested word size.
83 Metachunk* MetaspaceArena::allocate_new_chunk(size_t requested_word_size) {
84 assert_lock_strong(lock());
85
86 // Should this ever happen, we need to increase the maximum possible chunk size.
87 guarantee(requested_word_size <= chunklevel::MAX_CHUNK_WORD_SIZE,
88 "Requested size too large (" SIZE_FORMAT ") - max allowed size per allocation is " SIZE_FORMAT ".",
89 requested_word_size, chunklevel::MAX_CHUNK_WORD_SIZE);
90
91 const chunklevel_t max_level = chunklevel::level_fitting_word_size(requested_word_size);
92 const chunklevel_t preferred_level = MIN2(max_level, next_chunk_level());
93
94 Metachunk* c = _chunk_manager->get_chunk(preferred_level, max_level, requested_word_size);
95 if (c == NULL) {
96 return NULL;
97 }
98
99 assert(c->is_in_use(), "Wrong chunk state.");
100 assert(c->free_below_committed_words() >= requested_word_size, "Chunk not committed");
101 return c;
102 }
103
104 void MetaspaceArena::add_allocation_to_fbl(MetaWord* p, size_t word_size) {
105 if (_fbl == NULL) {
106 _fbl = new FreeBlocks(); // Create only on demand
107 }
108 _fbl->add_block(p, word_size);
109 }
110
111 MetaspaceArena::MetaspaceArena(ChunkManager* chunk_manager, const ArenaGrowthPolicy* growth_policy, int alignment_words,
112 Mutex* lock, SizeAtomicCounter* total_used_words_counter,
113 const char* name) :
114 _lock(lock),
115 _chunk_manager(chunk_manager),
116 _growth_policy(growth_policy),
117 _chunks(),
118 _alignment_words(alignment_words),
119 _fbl(NULL),
120 _total_used_words_counter(total_used_words_counter),
121 _name(name)
122 #ifdef ASSERT
123 , _first_fence(NULL)
124 #endif
125
126 {
127 UL(debug, ": born.");
128
129 // Update statistics
130 InternalStats::inc_num_arena_births();
131 }
132
133 MetaspaceArena::~MetaspaceArena() {
134 #ifdef ASSERT
135 verify();
136 if (Settings::use_allocation_guard()) {
137 verify_allocation_guards();
138 }
139 #endif
140
141 MutexLocker fcl(lock(), Mutex::_no_safepoint_check_flag);
142 MemRangeCounter return_counter;
143
144 Metachunk* c = _chunks.first();
145 Metachunk* c2 = NULL;
146
147 while (c) {
148 c2 = c->next();
149 return_counter.add(c->used_words());
150 DEBUG_ONLY(c->set_prev(NULL);)
151 DEBUG_ONLY(c->set_next(NULL);)
152 UL2(debug, "return chunk: " METACHUNK_FORMAT ".", METACHUNK_FORMAT_ARGS(c));
153 _chunk_manager->return_chunk(c);
154 // c may be invalid after return_chunk(c) was called. Don't access anymore.
155 c = c2;
156 }
157
158 UL2(info, "returned %d chunks, total capacity " SIZE_FORMAT " words.",
159 return_counter.count(), return_counter.total_size());
160
161 _total_used_words_counter->decrement_by(return_counter.total_size());
162 DEBUG_ONLY(chunk_manager()->verify();)
163 delete _fbl;
164 UL(debug, ": dies.");
165
166 // Update statistics
167 InternalStats::inc_num_arena_deaths();
168 }
169
170 // Attempt to enlarge the current chunk to make it large enough to hold at least
171 // requested_word_size additional words.
172 //
173 // On success, true is returned, false otherwise.
174 bool MetaspaceArena::attempt_enlarge_current_chunk(size_t requested_word_size) {
175 assert_lock_strong(lock());
176
177 Metachunk* c = current_chunk();
178 assert(c->free_words() < requested_word_size, "Sanity");
179
180 // Not if chunk enlargment is switched off...
181 if (Settings::enlarge_chunks_in_place() == false) {
182 return false;
183 }
184 // ... nor if we are already a root chunk ...
185 if (c->is_root_chunk()) {
186 return false;
187 }
188 // ... nor if the combined size of chunk content and new content would bring us above the size of a root chunk ...
189 if ((c->used_words() + requested_word_size) > metaspace::chunklevel::MAX_CHUNK_WORD_SIZE) {
190 return false;
191 }
192
193 const chunklevel_t new_level =
194 chunklevel::level_fitting_word_size(c->used_words() + requested_word_size);
195 assert(new_level < c->level(), "Sanity");
196
197 // Atm we only enlarge by one level (so, doubling the chunk in size). So, if the requested enlargement
198 // would require the chunk to more than double in size, we bail. But this covers about 99% of all cases,
199 // so this is good enough.
200 if (new_level < c->level() - 1) {
201 return false;
202 }
203 // This only works if chunk is the leader of its buddy pair (and also if buddy
204 // is free and unsplit, but that we cannot check outside of metaspace lock).
205 if (!c->is_leader()) {
206 return false;
207 }
208 // If the size added to the chunk would be larger than allowed for the next growth step
209 // dont enlarge.
210 if (next_chunk_level() > c->level()) {
211 return false;
212 }
213
214 bool success = _chunk_manager->attempt_enlarge_chunk(c);
215 assert(success == false || c->free_words() >= requested_word_size, "Sanity");
216 return success;
217 }
218
219 // Allocate memory from Metaspace.
220 // 1) Attempt to allocate from the free block list.
221 // 2) Attempt to allocate from the current chunk.
222 // 3) Attempt to enlarge the current chunk in place if it is too small.
223 // 4) Attempt to get a new chunk and allocate from that chunk.
224 // At any point, if we hit a commit limit, we return NULL.
225 MetaWord* MetaspaceArena::allocate(size_t requested_word_size) {
226 MutexLocker cl(lock(), Mutex::_no_safepoint_check_flag);
227 UL2(trace, "requested " SIZE_FORMAT " words.", requested_word_size);
228
229 MetaWord* p = NULL;
230 const size_t raw_word_size = get_raw_word_size_for_requested_word_size(requested_word_size, _alignment_words);
231
232 // Before bothering the arena proper, attempt to re-use a block from the free blocks list
233 if (_fbl != NULL && !_fbl->is_empty()) {
234 p = _fbl->remove_block(raw_word_size);
235 if (p != NULL) {
236 DEBUG_ONLY(InternalStats::inc_num_allocs_from_deallocated_blocks();)
237 UL2(trace, "taken from fbl (now: %d, " SIZE_FORMAT ").",
238 _fbl->count(), _fbl->total_size());
239 // Note: free blocks in freeblock dictionary still count as "used" as far as statistics go;
240 // therefore we have no need to adjust any usage counters (see epilogue of allocate_inner())
241 // and can just return here.
242 return p;
243 }
244 }
245
246 // Primary allocation
247 p = allocate_inner(requested_word_size);
248
249 #ifdef ASSERT
250 // Fence allocation
251 if (p != NULL && Settings::use_allocation_guard()) {
252 STATIC_ASSERT(is_aligned(sizeof(Fence), BytesPerWord));
253 MetaWord* guard = allocate_inner(sizeof(Fence) / BytesPerWord);
254 if (guard != NULL) {
255 // Ignore allocation errors for the fence to keep coding simple. If this
256 // happens (e.g. because right at this time we hit the Metaspace GC threshold)
257 // we miss adding this one fence. Not a big deal. Note that his would
258 // be pretty rare. Chances are much higher the primary allocation above
259 // would have already failed).
260 Fence* f = new(guard) Fence(_first_fence);
261 _first_fence = f;
262 }
263 }
264 #endif // ASSERT
265
266 return p;
267 }
268
269 // Allocate from the arena proper, once dictionary allocations and fencing are sorted out.
270 MetaWord* MetaspaceArena::allocate_inner(size_t requested_word_size) {
271
272 assert_lock_strong(lock());
273
274 const size_t raw_word_size = get_raw_word_size_for_requested_word_size(requested_word_size, _alignment_words);
275 MetaWord* p = NULL;
276 bool current_chunk_too_small = false;
277 bool commit_failure = false;
278
279 if (current_chunk() != NULL) {
280
281 // Attempt to satisfy the allocation from the current chunk.
282
283 // If the current chunk is too small to hold the requested size, attempt to enlarge it.
284 // If that fails, retire the chunk.
285 if (current_chunk()->free_words() < raw_word_size) {
286 if (!attempt_enlarge_current_chunk(raw_word_size)) {
287 current_chunk_too_small = true;
288 } else {
289 DEBUG_ONLY(InternalStats::inc_num_chunks_enlarged();)
290 UL(debug, "enlarged chunk.");
291 }
292 }
293
294 // Commit the chunk far enough to hold the requested word size. If that fails, we
295 // hit a limit (either GC threshold or MaxMetaspaceSize). In that case retire the
296 // chunk.
297 if (!current_chunk_too_small) {
298 if (!current_chunk()->ensure_committed_additional(raw_word_size)) {
299 UL2(info, "commit failure (requested size: " SIZE_FORMAT ")", raw_word_size);
300 commit_failure = true;
301 }
302 }
303
304 // Allocate from the current chunk. This should work now.
305 if (!current_chunk_too_small && !commit_failure) {
306 p = current_chunk()->allocate(raw_word_size);
307 assert(p != NULL, "Allocation from chunk failed.");
308 }
309 }
310
311 if (p == NULL) {
312 // If we are here, we either had no current chunk to begin with or it was deemed insufficient.
313 assert(current_chunk() == NULL ||
314 current_chunk_too_small || commit_failure, "Sanity");
315
316 Metachunk* new_chunk = allocate_new_chunk(raw_word_size);
317 if (new_chunk != NULL) {
318 UL2(debug, "allocated new chunk " METACHUNK_FORMAT " for requested word size " SIZE_FORMAT ".",
319 METACHUNK_FORMAT_ARGS(new_chunk), requested_word_size);
320
321 assert(new_chunk->free_below_committed_words() >= raw_word_size, "Sanity");
322 if (Settings::new_chunks_are_fully_committed()) {
323 assert(new_chunk->is_fully_committed(), "Chunk should be fully committed.");
324 }
325
326 // We have a new chunk. Before making it the current chunk, retire the old one.
327 if (current_chunk() != NULL) {
328 salvage_chunk(current_chunk());
329 DEBUG_ONLY(InternalStats::inc_num_chunks_retired();)
330 }
331
332 _chunks.add(new_chunk);
333
334 // Now, allocate from that chunk. That should work.
335 p = current_chunk()->allocate(raw_word_size);
336 assert(p != NULL, "Allocation from chunk failed.");
337 } else {
338 UL2(info, "failed to allocate new chunk for requested word size " SIZE_FORMAT ".", requested_word_size);
339 }
340 }
341
342 if (p == NULL) {
343 InternalStats::inc_num_allocs_failed_limit();
344 } else {
345 DEBUG_ONLY(InternalStats::inc_num_allocs();)
346 _total_used_words_counter->increment_by(raw_word_size);
347 }
348
349 SOMETIMES(verify_locked();)
350
351 if (p == NULL) {
352 UL(info, "allocation failed, returned NULL.");
353 } else {
354 UL2(trace, "after allocation: %u chunk(s), current:" METACHUNK_FULL_FORMAT,
355 _chunks.count(), METACHUNK_FULL_FORMAT_ARGS(current_chunk()));
356 UL2(trace, "returning " PTR_FORMAT ".", p2i(p));
357 }
358 return p;
359 }
360
361 // Prematurely returns a metaspace allocation to the _block_freelists
362 // because it is not needed anymore (requires CLD lock to be active).
363 void MetaspaceArena::deallocate_locked(MetaWord* p, size_t word_size) {
364 assert_lock_strong(lock());
365 // At this point a current chunk must exist since we only deallocate if we did allocate before.
366 assert(current_chunk() != NULL, "stray deallocation?");
367 assert(is_valid_area(p, word_size),
368 "Pointer range not part of this Arena and cannot be deallocated: (" PTR_FORMAT ".." PTR_FORMAT ").",
369 p2i(p), p2i(p + word_size));
370
371 UL2(trace, "deallocating " PTR_FORMAT ", word size: " SIZE_FORMAT ".",
372 p2i(p), word_size);
373
374 size_t raw_word_size = get_raw_word_size_for_requested_word_size(word_size, _alignment_words);
375 add_allocation_to_fbl(p, raw_word_size);
376
377 DEBUG_ONLY(verify_locked();)
378 }
379
380 // Prematurely returns a metaspace allocation to the _block_freelists because it is not
381 // needed anymore.
382 void MetaspaceArena::deallocate(MetaWord* p, size_t word_size) {
383 MutexLocker cl(lock(), Mutex::_no_safepoint_check_flag);
384 deallocate_locked(p, word_size);
385 }
386
387 // Update statistics. This walks all in-use chunks.
388 void MetaspaceArena::add_to_statistics(ArenaStats* out) const {
389 MutexLocker cl(lock(), Mutex::_no_safepoint_check_flag);
390
391 for (const Metachunk* c = _chunks.first(); c != NULL; c = c->next()) {
392 InUseChunkStats& ucs = out->_stats[c->level()];
393 ucs._num++;
394 ucs._word_size += c->word_size();
395 ucs._committed_words += c->committed_words();
396 ucs._used_words += c->used_words();
397 // Note: for free and waste, we only count what's committed.
398 if (c == current_chunk()) {
399 ucs._free_words += c->free_below_committed_words();
400 } else {
401 ucs._waste_words += c->free_below_committed_words();
402 }
403 }
404
405 if (_fbl != NULL) {
406 out->_free_blocks_num += _fbl->count();
407 out->_free_blocks_word_size += _fbl->total_size();
408 }
409
410 SOMETIMES(out->verify();)
411 }
412
413 // Convenience method to get the most important usage statistics.
414 // For deeper analysis use add_to_statistics().
415 void MetaspaceArena::usage_numbers(size_t* p_used_words, size_t* p_committed_words, size_t* p_capacity_words) const {
416 MutexLocker cl(lock(), Mutex::_no_safepoint_check_flag);
417 size_t used = 0, comm = 0, cap = 0;
418 for (const Metachunk* c = _chunks.first(); c != NULL; c = c->next()) {
419 used += c->used_words();
420 comm += c->committed_words();
421 cap += c->word_size();
422 }
423 if (p_used_words != NULL) {
424 *p_used_words = used;
425 }
426 if (p_committed_words != NULL) {
427 *p_committed_words = comm;
428 }
429 if (p_capacity_words != NULL) {
430 *p_capacity_words = cap;
431 }
432 }
433
434 #ifdef ASSERT
435
436 void MetaspaceArena::verify_locked() const {
437 assert_lock_strong(lock());
438 assert(_growth_policy != NULL && _chunk_manager != NULL, "Sanity");
439 _chunks.verify();
440 if (_fbl != NULL) {
441 _fbl->verify();
442 }
443 }
444
445 void MetaspaceArena::Fence::verify() const {
446 assert(_eye1 == EyeCatcher && _eye2 == EyeCatcher,
447 "Metaspace corruption: fence block at " PTR_FORMAT " broken.", p2i(this));
448 }
449
450 void MetaspaceArena::verify_allocation_guards() const {
451 assert(Settings::use_allocation_guard(), "Don't call with guards disabled.");
452 for (const Fence* f = _first_fence; f != NULL; f = f->next()) {
453 f->verify();
454 }
455 }
456
457 void MetaspaceArena::verify() const {
458 MutexLocker cl(lock(), Mutex::_no_safepoint_check_flag);
459 verify_locked();
460 }
461
462 // Returns true if the area indicated by pointer and size have actually been allocated
463 // from this arena.
464 bool MetaspaceArena::is_valid_area(MetaWord* p, size_t word_size) const {
465 assert(p != NULL && word_size > 0, "Sanity");
466 bool found = false;
467 for (const Metachunk* c = _chunks.first(); c != NULL && !found; c = c->next()) {
468 assert(c->is_valid_committed_pointer(p) ==
469 c->is_valid_committed_pointer(p + word_size - 1), "range intersects");
470 found = c->is_valid_committed_pointer(p);
471 }
472 return found;
473 }
474
475 #endif // ASSERT
476
477 void MetaspaceArena::print_on(outputStream* st) const {
478 MutexLocker fcl(_lock, Mutex::_no_safepoint_check_flag);
479 print_on_locked(st);
480 }
481
482 void MetaspaceArena::print_on_locked(outputStream* st) const {
483 assert_lock_strong(_lock);
484 st->print_cr("sm %s: %d chunks, total word size: " SIZE_FORMAT ", committed word size: " SIZE_FORMAT, _name,
485 _chunks.count(), _chunks.calc_word_size(), _chunks.calc_committed_word_size());
486 _chunks.print_on(st);
487 st->cr();
488 st->print_cr("growth-policy " PTR_FORMAT ", alignment %d, lock " PTR_FORMAT ", cm " PTR_FORMAT ", fbl " PTR_FORMAT,
489 p2i(_growth_policy), _alignment_words * BytesPerWord, p2i(_lock), p2i(_chunk_manager), p2i(_fbl));
490 }
491
492 } // namespace metaspace
493