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