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