1 /*
2 * Copyright (c) 2011, 2019, 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
25 #include "precompiled.hpp"
26
27 #include "aot/aotLoader.hpp"
28 #include "gc/shared/collectedHeap.hpp"
29 #include "logging/log.hpp"
30 #include "logging/logStream.hpp"
31 #include "memory/filemap.hpp"
32 #include "memory/metaspace.hpp"
33 #include "memory/metaspaceShared.hpp"
34 #include "memory/metaspaceTracer.hpp"
35 #include "memory/metaspace/chunkManager.hpp"
36 #include "memory/metaspace/classLoaderMetaspace.hpp"
37 #include "memory/metaspace/commitLimiter.hpp"
38 #include "memory/metaspace/metaspaceCommon.hpp"
39 #include "memory/metaspace/metaspaceEnums.hpp"
40 #include "memory/metaspace/metaspaceReport.hpp"
41 #include "memory/metaspace/metaspaceSizesSnapshot.hpp"
42 #include "memory/metaspace/runningCounters.hpp"
43 #include "memory/metaspace/virtualSpaceList.hpp"
44 #include "memory/universe.hpp"
45 #include "oops/compressedOops.hpp"
46 #include "runtime/init.hpp"
47 #include "runtime/java.hpp"
48 #include "runtime/orderAccess.hpp"
49 #include "services/memTracker.hpp"
50 #include "utilities/copy.hpp"
51 #include "utilities/debug.hpp"
52 #include "utilities/formatBuffer.hpp"
53 #include "utilities/globalDefinitions.hpp"
54
55
56 using metaspace::ChunkManager;
57 using metaspace::ClassLoaderMetaspace;
58 using metaspace::CommitLimiter;
59 using metaspace::MetaspaceType;
60 using metaspace::MetadataType;
61 using metaspace::MetaspaceReporter;
62 using metaspace::RunningCounters;
63 using metaspace::VirtualSpaceList;
64
65
66 // Used by MetaspaceCounters
67 size_t MetaspaceUtils::free_chunks_total_words(MetadataType mdtype) {
68 return is_class(mdtype) ? RunningCounters::free_chunks_words_class() : RunningCounters::free_chunks_words_nonclass();
69 }
70
71 size_t MetaspaceUtils::used_words() {
72 return RunningCounters::used_words();
73 }
74
75 size_t MetaspaceUtils::used_words(MetadataType mdtype) {
76 return is_class(mdtype) ? RunningCounters::used_words_class() : RunningCounters::used_words_nonclass();
77 }
78
79 size_t MetaspaceUtils::reserved_words() {
80 return RunningCounters::reserved_words();
81 }
82
83 size_t MetaspaceUtils::reserved_words(MetadataType mdtype) {
84 return is_class(mdtype) ? RunningCounters::reserved_words_class() : RunningCounters::reserved_words_nonclass();
85 }
86
87 size_t MetaspaceUtils::committed_words() {
88 return RunningCounters::committed_words();
89 }
90
91 size_t MetaspaceUtils::committed_words(MetadataType mdtype) {
92 return is_class(mdtype) ? RunningCounters::committed_words_class() : RunningCounters::committed_words_nonclass();
93 }
94
95
96
97 void MetaspaceUtils::print_metaspace_change(const metaspace::MetaspaceSizesSnapshot& pre_meta_values) {
98 const metaspace::MetaspaceSizesSnapshot meta_values;
99
100 // We print used and committed since these are the most useful at-a-glance vitals for Metaspace:
101 // - used tells you how much memory is actually used for metadata
102 // - committed tells you how much memory is committed for the purpose of metadata
103 // The difference between those two would be waste, which can have various forms (freelists,
104 // unused parts of committed chunks etc)
105 //
106 // Left out is reserved, since this is not as exciting as the first two values: for class space,
107 // it is a constant (to uninformed users, often confusingly large). For non-class space, it would
108 // be interesting since free chunks can be uncommitted, but for now it is left out.
109
110 if (Metaspace::using_class_space()) {
111 log_info(gc, metaspace)(HEAP_CHANGE_FORMAT" "
112 HEAP_CHANGE_FORMAT" "
113 HEAP_CHANGE_FORMAT,
114 HEAP_CHANGE_FORMAT_ARGS("Metaspace",
115 pre_meta_values.used(),
116 pre_meta_values.committed(),
117 meta_values.used(),
118 meta_values.committed()),
119 HEAP_CHANGE_FORMAT_ARGS("NonClass",
120 pre_meta_values.non_class_used(),
121 pre_meta_values.non_class_committed(),
122 meta_values.non_class_used(),
123 meta_values.non_class_committed()),
124 HEAP_CHANGE_FORMAT_ARGS("Class",
125 pre_meta_values.class_used(),
126 pre_meta_values.class_committed(),
127 meta_values.class_used(),
128 meta_values.class_committed()));
129 } else {
130 log_info(gc, metaspace)(HEAP_CHANGE_FORMAT,
131 HEAP_CHANGE_FORMAT_ARGS("Metaspace",
132 pre_meta_values.used(),
133 pre_meta_values.committed(),
134 meta_values.used(),
135 meta_values.committed()));
136 }
137 }
138
139
140 // Prints an ASCII representation of the given space.
141 void MetaspaceUtils::print_metaspace_map(outputStream* out, MetadataType mdtype) {
142 out->print_cr("-- not yet implemented ---");
143 }
144
145 // This will print out a basic metaspace usage report but
146 // unlike print_report() is guaranteed not to lock or to walk the CLDG.
147 void MetaspaceUtils::print_basic_report(outputStream* out, size_t scale) {
148 MetaspaceReporter::print_basic_report(out, scale);
149 }
150
151 // Prints a report about the current metaspace state.
152 // Optional parts can be enabled via flags.
153 // Function will walk the CLDG and will lock the expand lock; if that is not
154 // convenient, use print_basic_report() instead.
155 void MetaspaceUtils::print_full_report(outputStream* out, size_t scale) {
156 const int flags =
157 MetaspaceReporter::rf_show_loaders |
158 MetaspaceReporter::rf_break_down_by_chunktype |
159 MetaspaceReporter::rf_show_classes;
160 MetaspaceReporter::print_report(out, scale, flags);
161 }
162
163 void MetaspaceUtils::print_on(outputStream* out) {
164
165 // Used from all GCs. It first prints out totals, then, separately, the class space portion.
166
167 out->print_cr(" Metaspace "
168 "used " SIZE_FORMAT "K, "
169 "committed " SIZE_FORMAT "K, "
170 "reserved " SIZE_FORMAT "K",
171 used_bytes()/K,
172 committed_bytes()/K,
173 reserved_bytes()/K);
174
175 if (Metaspace::using_class_space()) {
176 const MetadataType ct = metaspace::ClassType;
177 out->print_cr(" class space "
178 "used " SIZE_FORMAT "K, "
179 "committed " SIZE_FORMAT "K, "
180 "reserved " SIZE_FORMAT "K",
181 used_bytes(ct)/K,
182 committed_bytes(ct)/K,
183 reserved_bytes(ct)/K);
184 }
185 }
186
187 #ifdef ASSERT
188 void MetaspaceUtils::verify(bool slow) {
189 if (Metaspace::initialized()) {
190
191 // Verify non-class chunkmanager...
192 ChunkManager* cm = ChunkManager::chunkmanager_nonclass();
193 cm->verify(slow);
194
195 // ... and space list.
196 VirtualSpaceList* vsl = VirtualSpaceList::vslist_nonclass();
197 vsl->verify(slow);
198
199 if (Metaspace::using_class_space()) {
200 // If we use compressed class pointers, verify class chunkmanager...
201 cm = ChunkManager::chunkmanager_class();
202 assert(cm != NULL, "Sanity");
203 cm->verify(slow);
204
205 // ... and class spacelist.
206 VirtualSpaceList* vsl = VirtualSpaceList::vslist_nonclass();
207 assert(vsl != NULL, "Sanity");
208 vsl->verify(slow);
209 }
210
211 }
212 }
213 #endif
214
215 ////////////////////////////////7
216 // MetaspaceGC methods
217
218 volatile size_t MetaspaceGC::_capacity_until_GC = 0;
219 uint MetaspaceGC::_shrink_factor = 0;
220 bool MetaspaceGC::_should_concurrent_collect = false;
221
222 // VM_CollectForMetadataAllocation is the vm operation used to GC.
223 // Within the VM operation after the GC the attempt to allocate the metadata
224 // should succeed. If the GC did not free enough space for the metaspace
225 // allocation, the HWM is increased so that another virtualspace will be
226 // allocated for the metadata. With perm gen the increase in the perm
227 // gen had bounds, MinMetaspaceExpansion and MaxMetaspaceExpansion. The
228 // metaspace policy uses those as the small and large steps for the HWM.
229 //
230 // After the GC the compute_new_size() for MetaspaceGC is called to
231 // resize the capacity of the metaspaces. The current implementation
232 // is based on the flags MinMetaspaceFreeRatio and MaxMetaspaceFreeRatio used
233 // to resize the Java heap by some GC's. New flags can be implemented
234 // if really needed. MinMetaspaceFreeRatio is used to calculate how much
235 // free space is desirable in the metaspace capacity to decide how much
236 // to increase the HWM. MaxMetaspaceFreeRatio is used to decide how much
237 // free space is desirable in the metaspace capacity before decreasing
238 // the HWM.
239
240 // Calculate the amount to increase the high water mark (HWM).
241 // Increase by a minimum amount (MinMetaspaceExpansion) so that
242 // another expansion is not requested too soon. If that is not
243 // enough to satisfy the allocation, increase by MaxMetaspaceExpansion.
244 // If that is still not enough, expand by the size of the allocation
245 // plus some.
246 size_t MetaspaceGC::delta_capacity_until_GC(size_t bytes) {
247 size_t min_delta = MinMetaspaceExpansion;
248 size_t max_delta = MaxMetaspaceExpansion;
249 size_t delta = align_up(bytes, Metaspace::commit_alignment());
250
251 if (delta <= min_delta) {
252 delta = min_delta;
253 } else if (delta <= max_delta) {
254 // Don't want to hit the high water mark on the next
255 // allocation so make the delta greater than just enough
256 // for this allocation.
257 delta = max_delta;
258 } else {
259 // This allocation is large but the next ones are probably not
260 // so increase by the minimum.
261 delta = delta + min_delta;
262 }
263
264 assert_is_aligned(delta, Metaspace::commit_alignment());
265
266 return delta;
267 }
268
269 size_t MetaspaceGC::capacity_until_GC() {
270 size_t value = OrderAccess::load_acquire(&_capacity_until_GC);
271 assert(value >= MetaspaceSize, "Not initialized properly?");
272 return value;
273 }
274
275 // Try to increase the _capacity_until_GC limit counter by v bytes.
276 // Returns true if it succeeded. It may fail if either another thread
277 // concurrently increased the limit or the new limit would be larger
278 // than MaxMetaspaceSize.
279 // On success, optionally returns new and old metaspace capacity in
280 // new_cap_until_GC and old_cap_until_GC respectively.
281 // On error, optionally sets can_retry to indicate whether if there is
282 // actually enough space remaining to satisfy the request.
283 bool MetaspaceGC::inc_capacity_until_GC(size_t v, size_t* new_cap_until_GC, size_t* old_cap_until_GC, bool* can_retry) {
284 assert_is_aligned(v, Metaspace::commit_alignment());
285
286 size_t old_capacity_until_GC = _capacity_until_GC;
287 size_t new_value = old_capacity_until_GC + v;
288
289 if (new_value < old_capacity_until_GC) {
290 // The addition wrapped around, set new_value to aligned max value.
291 new_value = align_down(max_uintx, Metaspace::commit_alignment());
292 }
293
294 if (new_value > MaxMetaspaceSize) {
295 if (can_retry != NULL) {
296 *can_retry = false;
297 }
298 return false;
299 }
300
301 if (can_retry != NULL) {
302 *can_retry = true;
303 }
304 size_t prev_value = Atomic::cmpxchg(new_value, &_capacity_until_GC, old_capacity_until_GC);
305
306 if (old_capacity_until_GC != prev_value) {
307 return false;
308 }
309
310 if (new_cap_until_GC != NULL) {
311 *new_cap_until_GC = new_value;
312 }
313 if (old_cap_until_GC != NULL) {
314 *old_cap_until_GC = old_capacity_until_GC;
315 }
316 return true;
317 }
318
319 size_t MetaspaceGC::dec_capacity_until_GC(size_t v) {
320 assert_is_aligned(v, Metaspace::commit_alignment());
321
322 return Atomic::sub(v, &_capacity_until_GC);
323 }
324
325 void MetaspaceGC::initialize() {
326 // Set the high-water mark to MaxMetapaceSize during VM initializaton since
327 // we can't do a GC during initialization.
328 _capacity_until_GC = MaxMetaspaceSize;
329 }
330
331 void MetaspaceGC::post_initialize() {
332 // Reset the high-water mark once the VM initialization is done.
333 _capacity_until_GC = MAX2(MetaspaceUtils::committed_bytes(), MetaspaceSize);
334 }
335
336 bool MetaspaceGC::can_expand(size_t word_size, bool is_class) {
337 // Check if the compressed class space is full.
338 if (is_class && Metaspace::using_class_space()) {
339 size_t class_committed = MetaspaceUtils::committed_bytes(metaspace::ClassType);
340 if (class_committed + word_size * BytesPerWord > CompressedClassSpaceSize) {
341 log_trace(gc, metaspace, freelist)("Cannot expand %s metaspace by " SIZE_FORMAT " words (CompressedClassSpaceSize = " SIZE_FORMAT " words)",
342 (is_class ? "class" : "non-class"), word_size, CompressedClassSpaceSize / sizeof(MetaWord));
343 return false;
344 }
345 }
346
347 // Check if the user has imposed a limit on the metaspace memory.
348 size_t committed_bytes = MetaspaceUtils::committed_bytes();
349 if (committed_bytes + word_size * BytesPerWord > MaxMetaspaceSize) {
350 log_trace(gc, metaspace, freelist)("Cannot expand %s metaspace by " SIZE_FORMAT " words (MaxMetaspaceSize = " SIZE_FORMAT " words)",
351 (is_class ? "class" : "non-class"), word_size, MaxMetaspaceSize / sizeof(MetaWord));
352 return false;
353 }
354
355 return true;
356 }
357
358 size_t MetaspaceGC::allowed_expansion() {
359 size_t committed_bytes = MetaspaceUtils::committed_bytes();
360 size_t capacity_until_gc = capacity_until_GC();
361
362 assert(capacity_until_gc >= committed_bytes,
363 "capacity_until_gc: " SIZE_FORMAT " < committed_bytes: " SIZE_FORMAT,
364 capacity_until_gc, committed_bytes);
365
366 size_t left_until_max = MaxMetaspaceSize - committed_bytes;
367 size_t left_until_GC = capacity_until_gc - committed_bytes;
368 size_t left_to_commit = MIN2(left_until_GC, left_until_max);
369 log_trace(gc, metaspace, freelist)("allowed expansion words: " SIZE_FORMAT
370 " (left_until_max: " SIZE_FORMAT ", left_until_GC: " SIZE_FORMAT ".",
371 left_to_commit / BytesPerWord, left_until_max / BytesPerWord, left_until_GC / BytesPerWord);
372
373 return left_to_commit / BytesPerWord;
374 }
375
376 void MetaspaceGC::compute_new_size() {
377 assert(_shrink_factor <= 100, "invalid shrink factor");
378 uint current_shrink_factor = _shrink_factor;
379 _shrink_factor = 0;
380
381 // Using committed_bytes() for used_after_gc is an overestimation, since the
382 // chunk free lists are included in committed_bytes() and the memory in an
383 // un-fragmented chunk free list is available for future allocations.
384 // However, if the chunk free lists becomes fragmented, then the memory may
385 // not be available for future allocations and the memory is therefore "in use".
386 // Including the chunk free lists in the definition of "in use" is therefore
387 // necessary. Not including the chunk free lists can cause capacity_until_GC to
388 // shrink below committed_bytes() and this has caused serious bugs in the past.
389 const size_t used_after_gc = MetaspaceUtils::committed_bytes();
390 const size_t capacity_until_GC = MetaspaceGC::capacity_until_GC();
391
392 const double minimum_free_percentage = MinMetaspaceFreeRatio / 100.0;
393 const double maximum_used_percentage = 1.0 - minimum_free_percentage;
394
395 const double min_tmp = used_after_gc / maximum_used_percentage;
396 size_t minimum_desired_capacity =
397 (size_t)MIN2(min_tmp, double(MaxMetaspaceSize));
398 // Don't shrink less than the initial generation size
399 minimum_desired_capacity = MAX2(minimum_desired_capacity,
400 MetaspaceSize);
401
402 log_trace(gc, metaspace)("MetaspaceGC::compute_new_size: ");
403 log_trace(gc, metaspace)(" minimum_free_percentage: %6.2f maximum_used_percentage: %6.2f",
404 minimum_free_percentage, maximum_used_percentage);
405 log_trace(gc, metaspace)(" used_after_gc : %6.1fKB", used_after_gc / (double) K);
406
407
408 size_t shrink_bytes = 0;
409 if (capacity_until_GC < minimum_desired_capacity) {
410 // If we have less capacity below the metaspace HWM, then
411 // increment the HWM.
412 size_t expand_bytes = minimum_desired_capacity - capacity_until_GC;
413 expand_bytes = align_up(expand_bytes, Metaspace::commit_alignment());
414 // Don't expand unless it's significant
415 if (expand_bytes >= MinMetaspaceExpansion) {
416 size_t new_capacity_until_GC = 0;
417 bool succeeded = MetaspaceGC::inc_capacity_until_GC(expand_bytes, &new_capacity_until_GC);
418 assert(succeeded, "Should always succesfully increment HWM when at safepoint");
419
420 Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
421 new_capacity_until_GC,
422 MetaspaceGCThresholdUpdater::ComputeNewSize);
423 log_trace(gc, metaspace)(" expanding: minimum_desired_capacity: %6.1fKB expand_bytes: %6.1fKB MinMetaspaceExpansion: %6.1fKB new metaspace HWM: %6.1fKB",
424 minimum_desired_capacity / (double) K,
425 expand_bytes / (double) K,
426 MinMetaspaceExpansion / (double) K,
427 new_capacity_until_GC / (double) K);
428 }
429 return;
430 }
431
432 // No expansion, now see if we want to shrink
433 // We would never want to shrink more than this
434 assert(capacity_until_GC >= minimum_desired_capacity,
435 SIZE_FORMAT " >= " SIZE_FORMAT,
436 capacity_until_GC, minimum_desired_capacity);
437 size_t max_shrink_bytes = capacity_until_GC - minimum_desired_capacity;
438
439 // Should shrinking be considered?
440 if (MaxMetaspaceFreeRatio < 100) {
441 const double maximum_free_percentage = MaxMetaspaceFreeRatio / 100.0;
442 const double minimum_used_percentage = 1.0 - maximum_free_percentage;
443 const double max_tmp = used_after_gc / minimum_used_percentage;
444 size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(MaxMetaspaceSize));
445 maximum_desired_capacity = MAX2(maximum_desired_capacity,
446 MetaspaceSize);
447 log_trace(gc, metaspace)(" maximum_free_percentage: %6.2f minimum_used_percentage: %6.2f",
448 maximum_free_percentage, minimum_used_percentage);
449 log_trace(gc, metaspace)(" minimum_desired_capacity: %6.1fKB maximum_desired_capacity: %6.1fKB",
450 minimum_desired_capacity / (double) K, maximum_desired_capacity / (double) K);
451
452 assert(minimum_desired_capacity <= maximum_desired_capacity,
453 "sanity check");
454
455 if (capacity_until_GC > maximum_desired_capacity) {
456 // Capacity too large, compute shrinking size
457 shrink_bytes = capacity_until_GC - maximum_desired_capacity;
458 // We don't want shrink all the way back to initSize if people call
459 // System.gc(), because some programs do that between "phases" and then
460 // we'd just have to grow the heap up again for the next phase. So we
461 // damp the shrinking: 0% on the first call, 10% on the second call, 40%
462 // on the third call, and 100% by the fourth call. But if we recompute
463 // size without shrinking, it goes back to 0%.
464 shrink_bytes = shrink_bytes / 100 * current_shrink_factor;
465
466 shrink_bytes = align_down(shrink_bytes, Metaspace::commit_alignment());
467
468 assert(shrink_bytes <= max_shrink_bytes,
469 "invalid shrink size " SIZE_FORMAT " not <= " SIZE_FORMAT,
470 shrink_bytes, max_shrink_bytes);
471 if (current_shrink_factor == 0) {
472 _shrink_factor = 10;
473 } else {
474 _shrink_factor = MIN2(current_shrink_factor * 4, (uint) 100);
475 }
476 log_trace(gc, metaspace)(" shrinking: initThreshold: %.1fK maximum_desired_capacity: %.1fK",
477 MetaspaceSize / (double) K, maximum_desired_capacity / (double) K);
478 log_trace(gc, metaspace)(" shrink_bytes: %.1fK current_shrink_factor: %d new shrink factor: %d MinMetaspaceExpansion: %.1fK",
479 shrink_bytes / (double) K, current_shrink_factor, _shrink_factor, MinMetaspaceExpansion / (double) K);
480 }
481 }
482
483 // Don't shrink unless it's significant
484 if (shrink_bytes >= MinMetaspaceExpansion &&
485 ((capacity_until_GC - shrink_bytes) >= MetaspaceSize)) {
486 size_t new_capacity_until_GC = MetaspaceGC::dec_capacity_until_GC(shrink_bytes);
487 Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
488 new_capacity_until_GC,
489 MetaspaceGCThresholdUpdater::ComputeNewSize);
490 }
491 }
492
493
494
495 ////// Metaspace methods /////
496
497
498
499 MetaWord* Metaspace::_compressed_class_space_base = NULL;
500 size_t Metaspace::_compressed_class_space_size = 0;
501 const MetaspaceTracer* Metaspace::_tracer = NULL;
502 bool Metaspace::_initialized = false;
503 size_t Metaspace::_commit_alignment = 0;
504 size_t Metaspace::_reserve_alignment = 0;
505
506 DEBUG_ONLY(bool Metaspace::_frozen = false;)
507
508
509 #ifdef _LP64
510 static const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
511
512 void Metaspace::set_narrow_klass_base_and_shift(address metaspace_base, address cds_base) {
513 assert(!DumpSharedSpaces, "narrow_klass is set by MetaspaceShared class.");
514 // Figure out the narrow_klass_base and the narrow_klass_shift. The
515 // narrow_klass_base is the lower of the metaspace base and the cds base
516 // (if cds is enabled). The narrow_klass_shift depends on the distance
517 // between the lower base and higher address.
518 address lower_base;
519 address higher_address;
520 #if INCLUDE_CDS
521 if (UseSharedSpaces) {
522 higher_address = MAX2((address)(cds_base + MetaspaceShared::core_spaces_size()),
523 (address)(metaspace_base + compressed_class_space_size()));
524 lower_base = MIN2(metaspace_base, cds_base);
525 } else
526 #endif
527 {
528 higher_address = metaspace_base + compressed_class_space_size();
529 lower_base = metaspace_base;
530
531 uint64_t klass_encoding_max = UnscaledClassSpaceMax << LogKlassAlignmentInBytes;
532 // If compressed class space fits in lower 32G, we don't need a base.
533 if (higher_address <= (address)klass_encoding_max) {
534 lower_base = 0; // Effectively lower base is zero.
535 }
536 }
537
538 CompressedKlassPointers::set_base(lower_base);
539
540 // CDS uses LogKlassAlignmentInBytes for narrow_klass_shift. See
541 // MetaspaceShared::initialize_dumptime_shared_and_meta_spaces() for
542 // how dump time narrow_klass_shift is set. Although, CDS can work
543 // with zero-shift mode also, to be consistent with AOT it uses
544 // LogKlassAlignmentInBytes for klass shift so archived java heap objects
545 // can be used at same time as AOT code.
546 if (!UseSharedSpaces
547 && (uint64_t)(higher_address - lower_base) <= UnscaledClassSpaceMax) {
548 CompressedKlassPointers::set_shift(0);
549 } else {
550 CompressedKlassPointers::set_shift(LogKlassAlignmentInBytes);
551 }
552 AOTLoader::set_narrow_klass_shift();
553 }
554
555 #if INCLUDE_CDS
556 // Return TRUE if the specified metaspace_base and cds_base are close enough
557 // to work with compressed klass pointers.
558 bool Metaspace::can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base) {
559 assert(cds_base != 0 && UseSharedSpaces, "Only use with CDS");
560 assert(UseCompressedClassPointers, "Only use with CompressedKlassPtrs");
561 address lower_base = MIN2((address)metaspace_base, cds_base);
562 address higher_address = MAX2((address)(cds_base + MetaspaceShared::core_spaces_size()),
563 (address)(metaspace_base + compressed_class_space_size()));
564 return ((uint64_t)(higher_address - lower_base) <= UnscaledClassSpaceMax);
565 }
566 #endif
567
568 // Try to allocate the metaspace at the requested addr.
569 void Metaspace::allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base) {
570 assert(!DumpSharedSpaces, "compress klass space is allocated by MetaspaceShared class.");
571 assert(using_class_space(), "called improperly");
572 assert(UseCompressedClassPointers, "Only use with CompressedKlassPtrs");
573 assert(compressed_class_space_size() < KlassEncodingMetaspaceMax,
574 "Metaspace size is too big");
575 assert_is_aligned(requested_addr, _reserve_alignment);
576 assert_is_aligned(cds_base, _reserve_alignment);
577 assert_is_aligned(compressed_class_space_size(), _reserve_alignment);
578
579 // Don't use large pages for the class space.
580 bool large_pages = false;
581
582 #if !(defined(AARCH64) || defined(AIX))
583 ReservedSpace rs = ReservedSpace(compressed_class_space_size(),
584 _reserve_alignment,
585 large_pages,
586 requested_addr);
587 #else // AARCH64
588 ReservedSpace rs;
589
590 // Our compressed klass pointers may fit nicely into the lower 32
591 // bits.
592 if ((uint64_t)requested_addr + compressed_class_space_size() < 4*G) {
593 rs = ReservedSpace(compressed_class_space_size(),
594 _reserve_alignment,
595 large_pages,
596 requested_addr);
597 }
598
599 if (! rs.is_reserved()) {
600 // Aarch64: Try to align metaspace so that we can decode a compressed
601 // klass with a single MOVK instruction. We can do this iff the
602 // compressed class base is a multiple of 4G.
603 // Aix: Search for a place where we can find memory. If we need to load
604 // the base, 4G alignment is helpful, too.
605 size_t increment = AARCH64_ONLY(4*)G;
606 for (char *a = align_up(requested_addr, increment);
607 a < (char*)(1024*G);
608 a += increment) {
609 if (a == (char *)(32*G)) {
610 // Go faster from here on. Zero-based is no longer possible.
611 increment = 4*G;
612 }
613
614 #if INCLUDE_CDS
615 if (UseSharedSpaces
616 && ! can_use_cds_with_metaspace_addr(a, cds_base)) {
617 // We failed to find an aligned base that will reach. Fall
618 // back to using our requested addr.
619 rs = ReservedSpace(compressed_class_space_size(),
620 _reserve_alignment,
621 large_pages,
622 requested_addr);
623 break;
624 }
625 #endif
626
627 rs = ReservedSpace(compressed_class_space_size(),
628 _reserve_alignment,
629 large_pages,
630 a);
631 if (rs.is_reserved())
632 break;
633 }
634 }
635
636 #endif // AARCH64
637
638 if (!rs.is_reserved()) {
639 #if INCLUDE_CDS
640 if (UseSharedSpaces) {
641 size_t increment = align_up(1*G, _reserve_alignment);
642
643 // Keep trying to allocate the metaspace, increasing the requested_addr
644 // by 1GB each time, until we reach an address that will no longer allow
645 // use of CDS with compressed klass pointers.
646 char *addr = requested_addr;
647 while (!rs.is_reserved() && (addr + increment > addr) &&
648 can_use_cds_with_metaspace_addr(addr + increment, cds_base)) {
649 addr = addr + increment;
650 rs = ReservedSpace(compressed_class_space_size(),
651 _reserve_alignment, large_pages, addr);
652 }
653 }
654 #endif
655 // If no successful allocation then try to allocate the space anywhere. If
656 // that fails then OOM doom. At this point we cannot try allocating the
657 // metaspace as if UseCompressedClassPointers is off because too much
658 // initialization has happened that depends on UseCompressedClassPointers.
659 // So, UseCompressedClassPointers cannot be turned off at this point.
660 if (!rs.is_reserved()) {
661 rs = ReservedSpace(compressed_class_space_size(),
662 _reserve_alignment, large_pages);
663 if (!rs.is_reserved()) {
664 vm_exit_during_initialization(err_msg("Could not allocate metaspace: " SIZE_FORMAT " bytes",
665 compressed_class_space_size()));
666 }
667 }
668 }
669
670 // If we got here then the metaspace got allocated.
671 MemTracker::record_virtual_memory_type((address)rs.base(), mtClass);
672
673 _compressed_class_space_base = (MetaWord*)rs.base();
674
675 #if INCLUDE_CDS
676 // Verify that we can use shared spaces. Otherwise, turn off CDS.
677 if (UseSharedSpaces && !can_use_cds_with_metaspace_addr(rs.base(), cds_base)) {
678 FileMapInfo::stop_sharing_and_unmap(
679 "Could not allocate metaspace at a compatible address");
680 }
681 #endif
682 set_narrow_klass_base_and_shift((address)rs.base(),
683 UseSharedSpaces ? (address)cds_base : 0);
684
685 initialize_class_space(rs);
686
687 LogTarget(Trace, gc, metaspace) lt;
688 if (lt.is_enabled()) {
689 ResourceMark rm;
690 LogStream ls(lt);
691 print_compressed_class_space(&ls, requested_addr);
692 }
693 }
694
695 // For UseCompressedClassPointers the class space is reserved above the top of
696 // the Java heap. The argument passed in is at the base of the compressed space.
697 void Metaspace::initialize_class_space(ReservedSpace rs) {
698
699 // The reserved space size may be bigger because of alignment, esp with UseLargePages
700 assert(rs.size() >= CompressedClassSpaceSize,
701 SIZE_FORMAT " != " SIZE_FORMAT, rs.size(), CompressedClassSpaceSize);
702 assert(using_class_space(), "Must be using class space");
703
704 VirtualSpaceList* vsl = new VirtualSpaceList("class space list", rs, CommitLimiter::globalLimiter());
705 VirtualSpaceList::set_vslist_class(vsl);
706 ChunkManager* cm = new ChunkManager("class space chunk manager", vsl);
707 ChunkManager::set_chunkmanager_class(cm);
708
709 }
710
711
712 void Metaspace::print_compressed_class_space(outputStream* st, const char* requested_addr) {
713 st->print_cr("Narrow klass base: " PTR_FORMAT ", Narrow klass shift: %d",
714 p2i(CompressedKlassPointers::base()), CompressedKlassPointers::shift());
715 if (Metaspace::using_class_space()) {
716 st->print("Compressed class space size: " SIZE_FORMAT " Address: " PTR_FORMAT,
717 compressed_class_space_size(), p2i(compressed_class_space_base()));
718 if (requested_addr != 0) {
719 st->print(" Req Addr: " PTR_FORMAT, p2i(requested_addr));
720 }
721 st->cr();
722 }
723 }
724
725 #endif
726
727 void Metaspace::ergo_initialize() {
728 if (DumpSharedSpaces) {
729 // Using large pages when dumping the shared archive is currently not implemented.
730 FLAG_SET_ERGO(UseLargePagesInMetaspace, false);
731 }
732
733 size_t page_size = os::vm_page_size();
734 if (UseLargePages && UseLargePagesInMetaspace) {
735 page_size = os::large_page_size();
736 }
737
738 // Commit alignment: (I would rather hide this since this is an implementation detail but we need it
739 // when calculating the gc threshold).
740 _commit_alignment = metaspace::constants::commit_granule_bytes;
741
742 // Reserve alignment: all Metaspace memory mappings are to be aligned to the size of a root chunk.
743 _reserve_alignment = MAX2(page_size, (size_t)metaspace::chklvl::MAX_CHUNK_BYTE_SIZE);
744
745 assert(is_aligned(_reserve_alignment, os::vm_allocation_granularity()),
746 "root chunk size must be a multiple of alloc granularity");
747
748 // Do not use FLAG_SET_ERGO to update MaxMetaspaceSize, since this will
749 // override if MaxMetaspaceSize was set on the command line or not.
750 // This information is needed later to conform to the specification of the
751 // java.lang.management.MemoryUsage API.
752 //
753 // Ideally, we would be able to set the default value of MaxMetaspaceSize in
754 // globals.hpp to the aligned value, but this is not possible, since the
755 // alignment depends on other flags being parsed.
756 MaxMetaspaceSize = align_down_bounded(MaxMetaspaceSize, _reserve_alignment);
757
758 if (MetaspaceSize > MaxMetaspaceSize) {
759 MetaspaceSize = MaxMetaspaceSize;
760 }
761
762 MetaspaceSize = align_down_bounded(MetaspaceSize, _commit_alignment);
763
764 assert(MetaspaceSize <= MaxMetaspaceSize, "MetaspaceSize should be limited by MaxMetaspaceSize");
765
766 MinMetaspaceExpansion = align_down_bounded(MinMetaspaceExpansion, _commit_alignment);
767 MaxMetaspaceExpansion = align_down_bounded(MaxMetaspaceExpansion, _commit_alignment);
768
769 CompressedClassSpaceSize = align_down_bounded(CompressedClassSpaceSize, _reserve_alignment);
770
771 // Note: InitialBootClassLoaderMetaspaceSize is an old parameter which is used to determine the chunk size
772 // of the first non-class chunk handed to the boot class loader. See metaspace/chunkAllocSequence.hpp.
773 size_t min_metaspace_sz = align_up(InitialBootClassLoaderMetaspaceSize, _reserve_alignment);
774 if (UseCompressedClassPointers) {
775 if (min_metaspace_sz >= MaxMetaspaceSize) {
776 vm_exit_during_initialization("MaxMetaspaceSize is too small.");
777 } else if ((min_metaspace_sz + CompressedClassSpaceSize) > MaxMetaspaceSize) {
778 FLAG_SET_ERGO(CompressedClassSpaceSize, MaxMetaspaceSize - min_metaspace_sz);
779 }
780 } else if (min_metaspace_sz >= MaxMetaspaceSize) {
781 FLAG_SET_ERGO(InitialBootClassLoaderMetaspaceSize,
782 min_metaspace_sz);
783 }
784
785 _compressed_class_space_size = CompressedClassSpaceSize;
786 }
787
788 void Metaspace::global_initialize() {
789 MetaspaceGC::initialize(); // <- since we do not prealloc init chunks anymore is this still needed?
790
791 #if INCLUDE_CDS
792 if (DumpSharedSpaces) {
793 MetaspaceShared::initialize_dumptime_shared_and_meta_spaces();
794 } else if (UseSharedSpaces) {
795 // If any of the archived space fails to map, UseSharedSpaces
796 // is reset to false. Fall through to the
797 // (!DumpSharedSpaces && !UseSharedSpaces) case to set up class
798 // metaspace.
799 MetaspaceShared::initialize_runtime_shared_and_meta_spaces();
800 }
801
802 if (DynamicDumpSharedSpaces && !UseSharedSpaces) {
803 vm_exit_during_initialization("DynamicDumpSharedSpaces is unsupported when base CDS archive is not loaded", NULL);
804 }
805 #endif // INCLUDE_CDS
806
807 // Initialize class space:
808 if (CDS_ONLY(!DumpSharedSpaces && !UseSharedSpaces) NOT_CDS(true)) {
809 #ifdef _LP64
810 if (using_class_space()) {
811 char* base = (char*)align_up(Universe::heap()->reserved_region().end(), _reserve_alignment);
812 allocate_metaspace_compressed_klass_ptrs(base, 0);
813 }
814 #endif // _LP64
815 }
816
817 // Initialize non-class virtual space list, and its chunk manager:
818 VirtualSpaceList* vsl = new VirtualSpaceList("Non-Class VirtualSpaceList", CommitLimiter::globalLimiter());
819 VirtualSpaceList::set_vslist_nonclass(vsl);
820 ChunkManager* cm = new ChunkManager("Non-Class ChunkManager", vsl);
821 ChunkManager::set_chunkmanager_nonclass(cm);
822
823 _tracer = new MetaspaceTracer();
824
825 _initialized = true;
826
827 }
828
829 void Metaspace::post_initialize() {
830 // TODO do we really need this? Metaspace should not be allocated during VM initialization.
831 assert(RunningCounters::committed_words() == 0, "CHECKECHK");
832 MetaspaceGC::post_initialize();
833 }
834
835 MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size,
836 MetaspaceObj::Type type, TRAPS) {
837 assert(!_frozen, "sanity");
838 assert(!(DumpSharedSpaces && THREAD->is_VM_thread()), "sanity");
839
840 if (HAS_PENDING_EXCEPTION) {
841 assert(false, "Should not allocate with exception pending");
842 return NULL; // caller does a CHECK_NULL too
843 }
844
845 assert(loader_data != NULL, "Should never pass around a NULL loader_data. "
846 "ClassLoaderData::the_null_class_loader_data() should have been used.");
847
848 MetadataType mdtype = (type == MetaspaceObj::ClassType) ? metaspace::ClassType : metaspace::NonClassType;
849
850 // Try to allocate metadata.
851 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
852
853 if (result == NULL) {
854 tracer()->report_metaspace_allocation_failure(loader_data, word_size, type, mdtype);
855
856 // Allocation failed.
857 if (is_init_completed()) {
858 // Only start a GC if the bootstrapping has completed.
859 // Try to clean out some heap memory and retry. This can prevent premature
860 // expansion of the metaspace.
861 result = Universe::heap()->satisfy_failed_metadata_allocation(loader_data, word_size, mdtype);
862 }
863 }
864
865 if (result == NULL) {
866 if (DumpSharedSpaces) {
867 // CDS dumping keeps loading classes, so if we hit an OOM we probably will keep hitting OOM.
868 // We should abort to avoid generating a potentially bad archive.
869 vm_exit_during_cds_dumping(err_msg("Failed allocating metaspace object type %s of size " SIZE_FORMAT ". CDS dump aborted.",
870 MetaspaceObj::type_name(type), word_size * BytesPerWord),
871 err_msg("Please increase MaxMetaspaceSize (currently " SIZE_FORMAT " bytes).", MaxMetaspaceSize));
872 }
873 report_metadata_oome(loader_data, word_size, type, mdtype, THREAD);
874 assert(HAS_PENDING_EXCEPTION, "sanity");
875 return NULL;
876 }
877
878 // Zero initialize.
879 Copy::fill_to_words((HeapWord*)result, word_size, 0);
880
881 return result;
882 }
883
884 void Metaspace::report_metadata_oome(ClassLoaderData* loader_data, size_t word_size, MetaspaceObj::Type type, MetadataType mdtype, TRAPS) {
885 tracer()->report_metadata_oom(loader_data, word_size, type, mdtype);
886
887 // If result is still null, we are out of memory.
888 Log(gc, metaspace, freelist, oom) log;
889 if (log.is_info()) {
890 log.info("Metaspace (%s) allocation failed for size " SIZE_FORMAT,
891 is_class(mdtype) ? "class" : "data", word_size);
892 ResourceMark rm;
893 if (log.is_debug()) {
894 if (loader_data->metaspace_or_null() != NULL) {
895 LogStream ls(log.debug());
896 loader_data->print_value_on(&ls);
897 }
898 }
899 LogStream ls(log.info());
900 // In case of an OOM, log out a short but still useful report.
901 MetaspaceUtils::print_basic_report(&ls, 0);
902 }
903
904 // Which limit did we hit? CompressedClassSpaceSize or MaxMetaspaceSize?
905 bool out_of_compressed_class_space = false;
906 if (is_class(mdtype)) {
907 ClassLoaderMetaspace* metaspace = loader_data->metaspace_non_null();
908 out_of_compressed_class_space =
909 MetaspaceUtils::committed_bytes(metaspace::ClassType) +
910 // TODO: Okay this is just cheesy.
911 // Of course this may fail and return incorrect results.
912 // Think this over - we need some clean way to remember which limit
913 // exactly we hit during an allocation. Some sort of allocation context structure?
914 align_up(word_size * BytesPerWord, 4 * M) >
915 CompressedClassSpaceSize;
916 }
917
918 // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
919 const char* space_string = out_of_compressed_class_space ?
920 "Compressed class space" : "Metaspace";
921
922 report_java_out_of_memory(space_string);
923
924 if (JvmtiExport::should_post_resource_exhausted()) {
925 JvmtiExport::post_resource_exhausted(
926 JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR,
927 space_string);
928 }
929
930 if (!is_init_completed()) {
931 vm_exit_during_initialization("OutOfMemoryError", space_string);
932 }
933
934 if (out_of_compressed_class_space) {
935 THROW_OOP(Universe::out_of_memory_error_class_metaspace());
936 } else {
937 THROW_OOP(Universe::out_of_memory_error_metaspace());
938 }
939 }
940
941 void Metaspace::purge() {
942 // Todo
943 }
944
945 bool Metaspace::contains(const void* ptr) {
946 if (MetaspaceShared::is_in_shared_metaspace(ptr)) {
947 return true;
948 }
949 return contains_non_shared(ptr);
950 }
951
952 bool Metaspace::contains_non_shared(const void* ptr) {
953 if (using_class_space() && VirtualSpaceList::vslist_class()->contains((MetaWord*)ptr)) {
954 return true;
955 }
956
957 return VirtualSpaceList::vslist_nonclass()->contains((MetaWord*)ptr);
958 }