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.
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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23 */
24 #ifndef SHARE_MEMORY_METASPACE_HPP
25 #define SHARE_MEMORY_METASPACE_HPP
26
27 #include "memory/allocation.hpp"
28 #include "memory/memRegion.hpp"
29 #include "memory/metaspaceChunkFreeListSummary.hpp"
30 #include "memory/virtualspace.hpp"
31 #include "utilities/exceptions.hpp"
32
33 // Metaspace
34 //
35 // Metaspaces are Arenas for the VM's metadata.
36 // They are allocated one per class loader object, and one for the null
37 // bootstrap class loader
38 //
39 // block X ---+ +-------------------+
40 // | | Virtualspace |
41 // | | |
42 // | | |
43 // | |-------------------|
44 // | || Chunk |
45 // | || |
46 // | ||---------- |
47 // +------>||| block 0 | |
48 // ||---------- |
49 // ||| block 1 | |
50 // ||---------- |
51 // || |
52 // |-------------------|
53 // | |
54 // | |
55 // +-------------------+
56 //
57
58 class ClassLoaderData;
59 class MetaspaceTracer;
60 class MetaWord;
61 class Mutex;
62 class outputStream;
63
64 class CollectedHeap;
65
66 namespace metaspace {
67 class ChunkManager;
68 class ClassLoaderMetaspaceStatistics;
69 class Metablock;
70 class Metachunk;
71 class PrintCLDMetaspaceInfoClosure;
72 class SpaceManager;
73 class VirtualSpaceList;
74 class VirtualSpaceNode;
75 }
76
77 // Metaspaces each have a SpaceManager and allocations
78 // are done by the SpaceManager. Allocations are done
79 // out of the current Metachunk. When the current Metachunk
80 // is exhausted, the SpaceManager gets a new one from
81 // the current VirtualSpace. When the VirtualSpace is exhausted
82 // the SpaceManager gets a new one. The SpaceManager
83 // also manages freelists of available Chunks.
84 //
85 // Currently the space manager maintains the list of
86 // virtual spaces and the list of chunks in use. Its
87 // allocate() method returns a block for use as a
88 // quantum of metadata.
89
90 // Namespace for important central static functions
91 // (auxiliary stuff goes into MetaspaceUtils)
92 class Metaspace : public AllStatic {
93
94 friend class MetaspaceShared;
95
96 public:
97 enum MetadataType {
98 ClassType,
99 NonClassType,
100 MetadataTypeCount
101 };
102 enum MetaspaceType {
103 ZeroMetaspaceType = 0,
104 StandardMetaspaceType = ZeroMetaspaceType,
105 BootMetaspaceType = StandardMetaspaceType + 1,
106 UnsafeAnonymousMetaspaceType = BootMetaspaceType + 1,
107 ReflectionMetaspaceType = UnsafeAnonymousMetaspaceType + 1,
108 MetaspaceTypeCount
109 };
110
111 private:
112
113 // Align up the word size to the allocation word size
114 static size_t align_word_size_up(size_t);
115
116 // Aligned size of the metaspace.
117 static size_t _compressed_class_space_size;
118
119 static size_t compressed_class_space_size() {
120 return _compressed_class_space_size;
121 }
122
123 static void set_compressed_class_space_size(size_t size) {
124 _compressed_class_space_size = size;
125 }
126
127 static size_t _first_chunk_word_size;
128 static size_t _first_class_chunk_word_size;
129
130 static size_t _commit_alignment;
131 static size_t _reserve_alignment;
132 DEBUG_ONLY(static bool _frozen;)
133
134 // Virtual Space lists for both classes and other metadata
135 static metaspace::VirtualSpaceList* _space_list;
136 static metaspace::VirtualSpaceList* _class_space_list;
137
138 static metaspace::ChunkManager* _chunk_manager_metadata;
139 static metaspace::ChunkManager* _chunk_manager_class;
140
141 static const MetaspaceTracer* _tracer;
142
143 public:
144 static metaspace::VirtualSpaceList* space_list() { return _space_list; }
145 static metaspace::VirtualSpaceList* class_space_list() { return _class_space_list; }
146 static metaspace::VirtualSpaceList* get_space_list(MetadataType mdtype) {
147 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
148 return mdtype == ClassType ? class_space_list() : space_list();
149 }
150
151 static metaspace::ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
152 static metaspace::ChunkManager* chunk_manager_class() { return _chunk_manager_class; }
153 static metaspace::ChunkManager* get_chunk_manager(MetadataType mdtype) {
154 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
155 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
156 }
157
158 // convenience function
159 static metaspace::ChunkManager* get_chunk_manager(bool is_class) {
160 return is_class ? chunk_manager_class() : chunk_manager_metadata();
161 }
162
163 static const MetaspaceTracer* tracer() { return _tracer; }
164 static void freeze() {
165 assert(DumpSharedSpaces, "sanity");
166 DEBUG_ONLY(_frozen = true;)
167 }
168 static void assert_not_frozen() {
169 assert(!_frozen, "sanity");
170 }
171 #ifdef _LP64
172 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
173 #endif
174
175 private:
176
177 #ifdef _LP64
178 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
179
180 // Returns true if can use CDS with metaspace allocated as specified address.
181 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
182
183 static void initialize_class_space(ReservedSpace rs);
184 #endif
185
186 public:
187
188 static void ergo_initialize();
189 static void global_initialize();
190 static void post_initialize();
191
192 static void verify_global_initialization();
193
194 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
195 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
196
197 static size_t reserve_alignment() { return _reserve_alignment; }
198 static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
199 static size_t commit_alignment() { return _commit_alignment; }
200 static size_t commit_alignment_words() { return _commit_alignment / BytesPerWord; }
201
202 static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
203 MetaspaceObj::Type type, TRAPS);
204
205 static bool contains(const void* ptr);
206 static bool contains_non_shared(const void* ptr);
207
208 // Free empty virtualspaces
209 static void purge(MetadataType mdtype);
210 static void purge();
211
212 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
213 MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
214
215 static const char* metadata_type_name(Metaspace::MetadataType mdtype);
216
217 static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
218
219 // Return TRUE only if UseCompressedClassPointers is True.
220 static bool using_class_space() {
221 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
222 }
223
224 static bool is_class_space_allocation(MetadataType mdType) {
225 return mdType == ClassType && using_class_space();
226 }
227
228 };
229
230 // Manages the metaspace portion belonging to a class loader
231 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
232 friend class CollectedHeap; // For expand_and_allocate()
233 friend class ZCollectedHeap; // For expand_and_allocate()
234 friend class ShenandoahHeap; // For expand_and_allocate()
235 friend class Metaspace;
236 friend class MetaspaceUtils;
237 friend class metaspace::PrintCLDMetaspaceInfoClosure;
238 friend class VM_CollectForMetadataAllocation; // For expand_and_allocate()
239
240 private:
241
242 void initialize(Mutex* lock, Metaspace::MetaspaceType type);
243
244 // Initialize the first chunk for a Metaspace. Used for
245 // special cases such as the boot class loader, reflection
246 // class loader and anonymous class loader.
247 void initialize_first_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
248 metaspace::Metachunk* get_initialization_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
249
250 const Metaspace::MetaspaceType _space_type;
251 Mutex* const _lock;
252 metaspace::SpaceManager* _vsm;
253 metaspace::SpaceManager* _class_vsm;
254
255 metaspace::SpaceManager* vsm() const { return _vsm; }
256 metaspace::SpaceManager* class_vsm() const { return _class_vsm; }
257 metaspace::SpaceManager* get_space_manager(Metaspace::MetadataType mdtype) {
258 assert(mdtype != Metaspace::MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
259 return mdtype == Metaspace::ClassType ? class_vsm() : vsm();
260 }
261
262 Mutex* lock() const { return _lock; }
263
264 MetaWord* expand_and_allocate(size_t size, Metaspace::MetadataType mdtype);
265
266 size_t class_chunk_size(size_t word_size);
267
268 // Adds to the given statistic object. Must be locked with CLD metaspace lock.
269 void add_to_statistics_locked(metaspace::ClassLoaderMetaspaceStatistics* out) const;
270
271 Metaspace::MetaspaceType space_type() const { return _space_type; }
272
273 public:
274
275 ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType type);
276 ~ClassLoaderMetaspace();
277
278 // Allocate space for metadata of type mdtype. This is space
279 // within a Metachunk and is used by
280 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
281 MetaWord* allocate(size_t word_size, Metaspace::MetadataType mdtype);
282
283 size_t allocated_blocks_bytes() const;
284 size_t allocated_chunks_bytes() const;
285
286 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
287
288 void print_on(outputStream* st) const;
289 // Debugging support
290 void verify();
291
292 // Adds to the given statistic object. Will lock with CLD metaspace lock.
293 void add_to_statistics(metaspace::ClassLoaderMetaspaceStatistics* out) const;
294
295 }; // ClassLoaderMetaspace
296
297 class MetaspaceUtils : AllStatic {
298
299 // Spacemanager updates running counters.
300 friend class metaspace::SpaceManager;
301
302 // Special access for error reporting (checks without locks).
303 friend class oopDesc;
304 friend class Klass;
305
306 // Running counters for statistics concerning in-use chunks.
307 // Note: capacity = used + free + waste + overhead. Note that we do not
308 // count free and waste. Their sum can be deduces from the three other values.
309 // For more details, one should call print_report() from within a safe point.
310 static size_t _capacity_words [Metaspace:: MetadataTypeCount];
311 static size_t _overhead_words [Metaspace:: MetadataTypeCount];
312 static volatile size_t _used_words [Metaspace:: MetadataTypeCount];
313
314 // Atomically decrement or increment in-use statistic counters
315 static void dec_capacity(Metaspace::MetadataType mdtype, size_t words);
316 static void inc_capacity(Metaspace::MetadataType mdtype, size_t words);
317 static void dec_used(Metaspace::MetadataType mdtype, size_t words);
318 static void inc_used(Metaspace::MetadataType mdtype, size_t words);
319 static void dec_overhead(Metaspace::MetadataType mdtype, size_t words);
320 static void inc_overhead(Metaspace::MetadataType mdtype, size_t words);
321
322
323 // Getters for the in-use counters.
324 static size_t capacity_words(Metaspace::MetadataType mdtype) { return _capacity_words[mdtype]; }
325 static size_t used_words(Metaspace::MetadataType mdtype) { return _used_words[mdtype]; }
326 static size_t overhead_words(Metaspace::MetadataType mdtype) { return _overhead_words[mdtype]; }
327
328 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
329
330 // Helper for print_xx_report.
331 static void print_vs(outputStream* out, size_t scale);
332
333 // Utils to check if a pointer or range is part of a committed metaspace region
334 // without acquiring any locks.
335 static metaspace::VirtualSpaceNode* find_enclosing_virtual_space(const void* p);
336 static bool is_range_in_committed(const void* from, const void* to);
337
338 public:
339
340 // Collect used metaspace statistics. This involves walking the CLDG. The resulting
341 // output will be the accumulated values for all live metaspaces.
342 // Note: method does not do any locking.
343 static void collect_statistics(metaspace::ClassLoaderMetaspaceStatistics* out);
344
345 // Used by MetaspaceCounters
346 static size_t free_chunks_total_words();
347 static size_t free_chunks_total_bytes();
348 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
349
350 static size_t capacity_words() {
351 return capacity_words(Metaspace::NonClassType) +
352 capacity_words(Metaspace::ClassType);
353 }
354 static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
355 return capacity_words(mdtype) * BytesPerWord;
356 }
357 static size_t capacity_bytes() {
358 return capacity_words() * BytesPerWord;
359 }
360
361 static size_t used_words() {
362 return used_words(Metaspace::NonClassType) +
363 used_words(Metaspace::ClassType);
364 }
365 static size_t used_bytes(Metaspace::MetadataType mdtype) {
366 return used_words(mdtype) * BytesPerWord;
367 }
368 static size_t used_bytes() {
369 return used_words() * BytesPerWord;
370 }
371
372 // Space committed but yet unclaimed by any class loader.
373 static size_t free_in_vs_bytes();
374 static size_t free_in_vs_bytes(Metaspace::MetadataType mdtype);
375
376 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
377 static size_t reserved_bytes() {
378 return reserved_bytes(Metaspace::ClassType) +
379 reserved_bytes(Metaspace::NonClassType);
380 }
381
382 static size_t committed_bytes(Metaspace::MetadataType mdtype);
383 static size_t committed_bytes() {
384 return committed_bytes(Metaspace::ClassType) +
385 committed_bytes(Metaspace::NonClassType);
386 }
387
388 static size_t min_chunk_size_words();
389
390 // Flags for print_report().
391 enum ReportFlag {
392 // Show usage by class loader.
393 rf_show_loaders = (1 << 0),
394 // Breaks report down by chunk type (small, medium, ...).
395 rf_break_down_by_chunktype = (1 << 1),
396 // Breaks report down by space type (anonymous, reflection, ...).
397 rf_break_down_by_spacetype = (1 << 2),
398 // Print details about the underlying virtual spaces.
399 rf_show_vslist = (1 << 3),
400 // Print metaspace map.
401 rf_show_vsmap = (1 << 4),
402 // If show_loaders: show loaded classes for each loader.
403 rf_show_classes = (1 << 5)
404 };
405
406 // This will print out a basic metaspace usage report but
407 // unlike print_report() is guaranteed not to lock or to walk the CLDG.
408 static void print_basic_report(outputStream* st, size_t scale);
409
410 // Prints a report about the current metaspace state.
411 // Optional parts can be enabled via flags.
412 // Function will walk the CLDG and will lock the expand lock; if that is not
413 // convenient, use print_basic_report() instead.
414 static void print_report(outputStream* out, size_t scale = 0, int flags = 0);
415
416 static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
417 static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
418
419 // Print change in used metadata.
420 static void print_metaspace_change(size_t prev_metadata_used);
421 static void print_on(outputStream * out);
422
423 // Prints an ASCII representation of the given space.
424 static void print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype);
425
426 static void dump(outputStream* out);
427 static void verify_free_chunks();
428 // Check internal counters (capacity, used).
429 static void verify_metrics();
430 };
431
432 // Metaspace are deallocated when their class loader are GC'ed.
433 // This class implements a policy for inducing GC's to recover
434 // Metaspaces.
435
436 class MetaspaceGC : AllStatic {
437
438 // The current high-water-mark for inducing a GC.
439 // When committed memory of all metaspaces reaches this value,
440 // a GC is induced and the value is increased. Size is in bytes.
441 static volatile size_t _capacity_until_GC;
442
443 // For a CMS collection, signal that a concurrent collection should
444 // be started.
445 static bool _should_concurrent_collect;
446
447 static uint _shrink_factor;
448
449 static size_t shrink_factor() { return _shrink_factor; }
450 void set_shrink_factor(uint v) { _shrink_factor = v; }
451
452 public:
453
454 static void initialize();
455 static void post_initialize();
456
457 static size_t capacity_until_GC();
458 static bool inc_capacity_until_GC(size_t v,
459 size_t* new_cap_until_GC = NULL,
460 size_t* old_cap_until_GC = NULL);
461 static size_t dec_capacity_until_GC(size_t v);
462
463 static bool should_concurrent_collect() { return _should_concurrent_collect; }
464 static void set_should_concurrent_collect(bool v) {
465 _should_concurrent_collect = v;
466 }
467
468 // The amount to increase the high-water-mark (_capacity_until_GC)
469 static size_t delta_capacity_until_GC(size_t bytes);
470
471 // Tells if we have can expand metaspace without hitting set limits.
472 static bool can_expand(size_t words, bool is_class);
473
474 // Returns amount that we can expand without hitting a GC,
475 // measured in words.
476 static size_t allowed_expansion();
477
478 // Calculate the new high-water mark at which to induce
479 // a GC.
480 static void compute_new_size();
481 };
482
483 #endif // SHARE_MEMORY_METASPACE_HPP