1 /*
2 * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2020, 2023 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 size_t remaining_words = c->free_below_committed_words();
62 if (remaining_words >= FreeBlocks::MinWordSize) {
63
64 UL2(trace, "salvaging chunk " METACHUNK_FULL_FORMAT ".", METACHUNK_FULL_FORMAT_ARGS(c));
65
66 MetaWord* ptr = c->allocate(remaining_words);
67 assert(ptr != nullptr, "Should have worked");
68 _total_used_words_counter->increment_by(remaining_words);
69
70 add_allocation_to_fbl(ptr, remaining_words);
71
72 // After this operation: the chunk should have no free committed space left.
73 assert(c->free_below_committed_words() == 0,
74 "Salvaging chunk failed (chunk " METACHUNK_FULL_FORMAT ").",
75 METACHUNK_FULL_FORMAT_ARGS(c));
76 }
77 }
78
79 // Allocate a new chunk from the underlying chunk manager able to hold at least
80 // requested word size.
81 Metachunk* MetaspaceArena::allocate_new_chunk(size_t requested_word_size) {
82 // Should this ever happen, we need to increase the maximum possible chunk size.
83 guarantee(requested_word_size <= chunklevel::MAX_CHUNK_WORD_SIZE,
84 "Requested size too large (" SIZE_FORMAT ") - max allowed size per allocation is " SIZE_FORMAT ".",
85 requested_word_size, chunklevel::MAX_CHUNK_WORD_SIZE);
86
87 const chunklevel_t max_level = chunklevel::level_fitting_word_size(requested_word_size);
88 const chunklevel_t preferred_level = MIN2(max_level, next_chunk_level());
89
90 Metachunk* c = _chunk_manager->get_chunk(preferred_level, max_level, requested_word_size);
91 if (c == nullptr) {
92 return nullptr;
93 }
94
95 assert(c->is_in_use(), "Wrong chunk state.");
96 assert(c->free_below_committed_words() >= requested_word_size, "Chunk not committed");
97 return c;
98 }
99
100 void MetaspaceArena::add_allocation_to_fbl(MetaWord* p, size_t word_size) {
101 assert(p != nullptr, "p is null");
102 assert_is_aligned_metaspace_pointer(p);
103 assert(word_size > 0, "zero sized");
104
105 if (_fbl == nullptr) {
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,
112 SizeAtomicCounter* total_used_words_counter,
113 const char* name) :
114 _chunk_manager(chunk_manager),
115 _growth_policy(growth_policy),
116 _chunks(),
117 _fbl(nullptr),
118 _total_used_words_counter(total_used_words_counter),
119 _name(name)
120 #ifdef ASSERT
121 , _first_fence(nullptr)
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 SOMETIMES(verify();)
133 if (Settings::use_allocation_guard()) {
134 verify_allocation_guards();
135 }
136 #endif
137 MemRangeCounter return_counter;
138
139 Metachunk* c = _chunks.first();
140 Metachunk* c2 = nullptr;
141
142 while (c) {
143 c2 = c->next();
144 return_counter.add(c->used_words());
145 DEBUG_ONLY(c->set_prev(nullptr);)
146 DEBUG_ONLY(c->set_next(nullptr);)
147 UL2(debug, "return chunk: " METACHUNK_FORMAT ".", METACHUNK_FORMAT_ARGS(c));
148 _chunk_manager->return_chunk(c);
149 // c may be invalid after return_chunk(c) was called. Don't access anymore.
150 c = c2;
151 }
152
153 UL2(info, "returned %d chunks, total capacity " SIZE_FORMAT " words.",
154 return_counter.count(), return_counter.total_size());
155
156 _total_used_words_counter->decrement_by(return_counter.total_size());
157 SOMETIMES(chunk_manager()->verify();)
158 delete _fbl;
159 UL(debug, ": dies.");
160
161 // Update statistics
162 InternalStats::inc_num_arena_deaths();
163 }
164
165 // Attempt to enlarge the current chunk to make it large enough to hold at least
166 // requested_word_size additional words.
167 //
168 // On success, true is returned, false otherwise.
169 bool MetaspaceArena::attempt_enlarge_current_chunk(size_t requested_word_size) {
170 Metachunk* c = current_chunk();
171 assert(c->free_words() < requested_word_size, "Sanity");
172
173 // Not if chunk enlargement is switched off...
174 if (Settings::enlarge_chunks_in_place() == false) {
175 return false;
176 }
177 // ... nor if we are already a root chunk ...
178 if (c->is_root_chunk()) {
179 return false;
180 }
181 // ... nor if the combined size of chunk content and new content would bring us above the size of a root chunk ...
182 if ((c->used_words() + requested_word_size) > metaspace::chunklevel::MAX_CHUNK_WORD_SIZE) {
183 return false;
184 }
185
186 const chunklevel_t new_level =
187 chunklevel::level_fitting_word_size(c->used_words() + requested_word_size);
188 assert(new_level < c->level(), "Sanity");
189
190 // Atm we only enlarge by one level (so, doubling the chunk in size). So, if the requested enlargement
191 // would require the chunk to more than double in size, we bail. But this covers about 99% of all cases,
192 // so this is good enough.
193 if (new_level < c->level() - 1) {
194 return false;
195 }
196 // This only works if chunk is the leader of its buddy pair (and also if buddy
197 // is free and unsplit, but that we cannot check outside of metaspace lock).
198 if (!c->is_leader()) {
199 return false;
200 }
201 // If the size added to the chunk would be larger than allowed for the next growth step
202 // dont enlarge.
203 if (next_chunk_level() > c->level()) {
204 return false;
205 }
206
207 bool success = _chunk_manager->attempt_enlarge_chunk(c);
208 assert(success == false || c->free_words() >= requested_word_size, "Sanity");
209 return success;
210 }
211
212 // Allocate memory from Metaspace.
213 // 1) Attempt to allocate from the free block list.
214 // 2) Attempt to allocate from the current chunk.
215 // 3) Attempt to enlarge the current chunk in place if it is too small.
216 // 4) Attempt to get a new chunk and allocate from that chunk.
217 // At any point, if we hit a commit limit, we return null.
218 MetaWord* MetaspaceArena::allocate(size_t requested_word_size) {
219 UL2(trace, "requested " SIZE_FORMAT " words.", requested_word_size);
220
221 MetaWord* p = nullptr;
222 const size_t aligned_word_size = get_raw_word_size_for_requested_word_size(requested_word_size);
223
224 // Before bothering the arena proper, attempt to re-use a block from the free blocks list
225 if (_fbl != nullptr && !_fbl->is_empty()) {
226 p = _fbl->remove_block(aligned_word_size);
227 if (p != nullptr) {
228 DEBUG_ONLY(InternalStats::inc_num_allocs_from_deallocated_blocks();)
229 UL2(trace, "returning " PTR_FORMAT " - taken from fbl (now: %d, " SIZE_FORMAT ").",
230 p2i(p), _fbl->count(), _fbl->total_size());
231 assert_is_aligned_metaspace_pointer(p);
232 // Note: free blocks in freeblock dictionary still count as "used" as far as statistics go;
233 // therefore we have no need to adjust any usage counters (see epilogue of allocate_inner())
234 // and can just return here.
235 return p;
236 }
237 }
238
239 // Primary allocation
240 p = allocate_inner(aligned_word_size);
241
242 #ifdef ASSERT
243 // Fence allocation
244 if (p != nullptr && Settings::use_allocation_guard()) {
245 STATIC_ASSERT(is_aligned(sizeof(Fence), BytesPerWord));
246 MetaWord* guard = allocate_inner(sizeof(Fence) / BytesPerWord);
247 if (guard != nullptr) {
248 // Ignore allocation errors for the fence to keep coding simple. If this
249 // happens (e.g. because right at this time we hit the Metaspace GC threshold)
250 // we miss adding this one fence. Not a big deal. Note that his would
251 // be pretty rare. Chances are much higher the primary allocation above
252 // would have already failed).
253 Fence* f = new(guard) Fence(_first_fence);
254 _first_fence = f;
255 }
256 }
257 #endif // ASSERT
258
259 return p;
260 }
261
262 // Allocate from the arena proper, once dictionary allocations and fencing are sorted out.
263 MetaWord* MetaspaceArena::allocate_inner(size_t word_size) {
264 assert_is_aligned(word_size, metaspace::AllocationAlignmentWordSize);
265
266 MetaWord* p = nullptr;
267 bool current_chunk_too_small = false;
268 bool commit_failure = false;
269
270 if (current_chunk() != nullptr) {
271
272 // Attempt to satisfy the allocation from the current chunk.
273
274 // If the current chunk is too small to hold the requested size, attempt to enlarge it.
275 // If that fails, retire the chunk.
276 if (current_chunk()->free_words() < word_size) {
277 if (!attempt_enlarge_current_chunk(word_size)) {
278 current_chunk_too_small = true;
279 } else {
280 DEBUG_ONLY(InternalStats::inc_num_chunks_enlarged();)
281 UL(debug, "enlarged chunk.");
282 }
283 }
284
285 // Commit the chunk far enough to hold the requested word size. If that fails, we
286 // hit a limit (either GC threshold or MaxMetaspaceSize). In that case retire the
287 // chunk.
288 if (!current_chunk_too_small) {
289 if (!current_chunk()->ensure_committed_additional(word_size)) {
290 UL2(info, "commit failure (requested size: " SIZE_FORMAT ")", word_size);
291 commit_failure = true;
292 }
293 }
294
295 // Allocate from the current chunk. This should work now.
296 if (!current_chunk_too_small && !commit_failure) {
297 p = current_chunk()->allocate(word_size);
298 assert(p != nullptr, "Allocation from chunk failed.");
299 }
300 }
301
302 if (p == nullptr) {
303 // If we are here, we either had no current chunk to begin with or it was deemed insufficient.
304 assert(current_chunk() == nullptr ||
305 current_chunk_too_small || commit_failure, "Sanity");
306
307 Metachunk* new_chunk = allocate_new_chunk(word_size);
308 if (new_chunk != nullptr) {
309 UL2(debug, "allocated new chunk " METACHUNK_FORMAT " for requested word size " SIZE_FORMAT ".",
310 METACHUNK_FORMAT_ARGS(new_chunk), word_size);
311
312 assert(new_chunk->free_below_committed_words() >= word_size, "Sanity");
313
314 // We have a new chunk. Before making it the current chunk, retire the old one.
315 if (current_chunk() != nullptr) {
316 salvage_chunk(current_chunk());
317 DEBUG_ONLY(InternalStats::inc_num_chunks_retired();)
318 }
319
320 _chunks.add(new_chunk);
321
322 // Now, allocate from that chunk. That should work.
323 p = current_chunk()->allocate(word_size);
324 assert(p != nullptr, "Allocation from chunk failed.");
325 } else {
326 UL2(info, "failed to allocate new chunk for requested word size " SIZE_FORMAT ".", word_size);
327 }
328 }
329
330 if (p == nullptr) {
331 InternalStats::inc_num_allocs_failed_limit();
332 } else {
333 DEBUG_ONLY(InternalStats::inc_num_allocs();)
334 _total_used_words_counter->increment_by(word_size);
335 }
336
337 SOMETIMES(verify();)
338
339 if (p == nullptr) {
340 UL(info, "allocation failed, returned null.");
341 } else {
342 UL2(trace, "after allocation: %u chunk(s), current:" METACHUNK_FULL_FORMAT,
343 _chunks.count(), METACHUNK_FULL_FORMAT_ARGS(current_chunk()));
344 UL2(trace, "returning " PTR_FORMAT ".", p2i(p));
345 }
346
347 assert_is_aligned_metaspace_pointer(p);
348
349 return p;
350 }
351
352 // Prematurely returns a metaspace allocation to the _block_freelists
353 // because it is not needed anymore (requires CLD lock to be active).
354 void MetaspaceArena::deallocate(MetaWord* p, size_t word_size) {
355 // At this point a current chunk must exist since we only deallocate if we did allocate before.
356 assert(current_chunk() != nullptr, "stray deallocation?");
357 assert(is_valid_area(p, word_size),
358 "Pointer range not part of this Arena and cannot be deallocated: (" PTR_FORMAT ".." PTR_FORMAT ").",
359 p2i(p), p2i(p + word_size));
360
361 UL2(trace, "deallocating " PTR_FORMAT ", word size: " SIZE_FORMAT ".",
362 p2i(p), word_size);
363
364 // Only blocks that had been allocated via MetaspaceArena::allocate(size) must be handed in
365 // to MetaspaceArena::deallocate(), and only with the same size that had been original used for allocation.
366 // Therefore the pointer must be aligned correctly, and size can be alignment-adjusted (the latter
367 // only matters on 32-bit):
368 assert_is_aligned_metaspace_pointer(p);
369 size_t raw_word_size = get_raw_word_size_for_requested_word_size(word_size);
370
371 add_allocation_to_fbl(p, raw_word_size);
372
373 SOMETIMES(verify();)
374 }
375
376 // Update statistics. This walks all in-use chunks.
377 void MetaspaceArena::add_to_statistics(ArenaStats* out) const {
378 for (const Metachunk* c = _chunks.first(); c != nullptr; c = c->next()) {
379 InUseChunkStats& ucs = out->_stats[c->level()];
380 ucs._num++;
381 ucs._word_size += c->word_size();
382 ucs._committed_words += c->committed_words();
383 ucs._used_words += c->used_words();
384 // Note: for free and waste, we only count what's committed.
385 if (c == current_chunk()) {
386 ucs._free_words += c->free_below_committed_words();
387 } else {
388 ucs._waste_words += c->free_below_committed_words();
389 }
390 }
391
392 if (_fbl != nullptr) {
393 out->_free_blocks_num += _fbl->count();
394 out->_free_blocks_word_size += _fbl->total_size();
395 }
396
397 SOMETIMES(out->verify();)
398 }
399
400 // Convenience method to get the most important usage statistics.
401 // For deeper analysis use add_to_statistics().
402 void MetaspaceArena::usage_numbers(size_t* p_used_words, size_t* p_committed_words, size_t* p_capacity_words) const {
403 size_t used = 0, comm = 0, cap = 0;
404 for (const Metachunk* c = _chunks.first(); c != nullptr; c = c->next()) {
405 used += c->used_words();
406 comm += c->committed_words();
407 cap += c->word_size();
408 }
409 if (p_used_words != nullptr) {
410 *p_used_words = used;
411 }
412 if (p_committed_words != nullptr) {
413 *p_committed_words = comm;
414 }
415 if (p_capacity_words != nullptr) {
416 *p_capacity_words = cap;
417 }
418 }
419
420 #ifdef ASSERT
421
422 void MetaspaceArena::verify() const {
423 assert(_growth_policy != nullptr && _chunk_manager != nullptr, "Sanity");
424 _chunks.verify();
425 if (_fbl != nullptr) {
426 _fbl->verify();
427 }
428 }
429
430 void MetaspaceArena::Fence::verify() const {
431 assert(_eye1 == EyeCatcher && _eye2 == EyeCatcher,
432 "Metaspace corruption: fence block at " PTR_FORMAT " broken.", p2i(this));
433 }
434
435 void MetaspaceArena::verify_allocation_guards() const {
436 assert(Settings::use_allocation_guard(), "Don't call with guards disabled.");
437 for (const Fence* f = _first_fence; f != nullptr; f = f->next()) {
438 f->verify();
439 }
440 }
441
442 // Returns true if the area indicated by pointer and size have actually been allocated
443 // from this arena.
444 bool MetaspaceArena::is_valid_area(MetaWord* p, size_t word_size) const {
445 assert(p != nullptr && word_size > 0, "Sanity");
446 bool found = false;
447 for (const Metachunk* c = _chunks.first(); c != nullptr && !found; c = c->next()) {
448 assert(c->is_valid_committed_pointer(p) ==
449 c->is_valid_committed_pointer(p + word_size - 1), "range intersects");
450 found = c->is_valid_committed_pointer(p);
451 }
452 return found;
453 }
454
455 #endif // ASSERT
456
457 void MetaspaceArena::print_on(outputStream* st) const {
458 st->print_cr("sm %s: %d chunks, total word size: " SIZE_FORMAT ", committed word size: " SIZE_FORMAT, _name,
459 _chunks.count(), _chunks.calc_word_size(), _chunks.calc_committed_word_size());
460 _chunks.print_on(st);
461 st->cr();
462 st->print_cr("growth-policy " PTR_FORMAT ", cm " PTR_FORMAT ", fbl " PTR_FORMAT,
463 p2i(_growth_policy), p2i(_chunk_manager), p2i(_fbl));
464 }
465
466 } // namespace metaspace
467