1 /*
2 * Copyright (c) 2011, 2020, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 "runtime/globals.hpp"
32 #include "utilities/exceptions.hpp"
33 #include "utilities/globalDefinitions.hpp"
34
35 class ClassLoaderData;
36 class MetaspaceShared;
37 class MetaspaceTracer;
38 class Mutex;
39 class outputStream;
40
41 namespace metaspace {
42 class MetaspaceArena;
43 class MetaspaceSizesSnapshot;
44 struct clms_stats_t;
45 }
46
47 ////////////////// Metaspace ///////////////////////
48
49 // Namespace for important central static functions
50 // (auxiliary stuff goes into MetaspaceUtils)
51 class Metaspace : public AllStatic {
52
53 friend class MetaspaceShared;
54
55 public:
56 enum MetadataType {
57 ClassType,
58 NonClassType,
59 MetadataTypeCount
60 };
61 enum MetaspaceType {
62 ZeroMetaspaceType = 0,
63 StandardMetaspaceType = ZeroMetaspaceType,
64 BootMetaspaceType = StandardMetaspaceType + 1,
65 ClassMirrorHolderMetaspaceType = BootMetaspaceType + 1,
66 ReflectionMetaspaceType = ClassMirrorHolderMetaspaceType + 1,
67 MetaspaceTypeCount
68 };
69
70 private:
71
72 DEBUG_ONLY(static bool _frozen;)
73
74 static const MetaspaceTracer* _tracer;
75
76 static bool _initialized;
77
78 public:
79
80 static const MetaspaceTracer* tracer() { return _tracer; }
81 static void freeze() {
82 assert(DumpSharedSpaces, "sanity");
83 DEBUG_ONLY(_frozen = true;)
84 }
85 static void assert_not_frozen() {
86 assert(!_frozen, "sanity");
87 }
88
89 private:
90
91 #ifdef _LP64
92
93 // Reserve a range of memory at an address suitable for en/decoding narrow
94 // Klass pointers (see: CompressedClassPointers::is_valid_base()).
95 // The returned address shall both be suitable as a compressed class pointers
96 // base, and aligned to Metaspace::reserve_alignment (which is equal to or a
97 // multiple of allocation granularity).
98 // On error, returns an unreserved space.
99 static ReservedSpace reserve_address_space_for_compressed_classes(size_t size);
100
101 // Given a prereserved space, use that to set up the compressed class space list.
102 static void initialize_class_space(ReservedSpace rs);
103
104 // Returns true if class space has been setup (initialize_class_space).
105 static bool class_space_is_initialized();
106
107 #endif
108
109 public:
110
111 static void ergo_initialize();
112 static void global_initialize();
113 static void post_initialize();
114
115 // Alignment, in bytes, of metaspace mappings
116 static size_t reserve_alignment() { return reserve_alignment_words() * BytesPerWord; }
117 // Alignment, in words, of metaspace mappings
118 static size_t reserve_alignment_words();
119
120 // The granularity at which Metaspace is committed and uncommitted.
121 // (Todo: Why does this have to be exposed?)
122 static size_t commit_alignment() { return commit_alignment_words() * BytesPerWord; }
123 static size_t commit_alignment_words();
124
125 // The largest possible single allocation
126 static size_t max_allocation_word_size();
127
128 static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
129 MetaspaceObj::Type type, TRAPS);
130
131 static bool contains(const void* ptr);
132 static bool contains_non_shared(const void* ptr);
133
134 // Free empty virtualspaces
135 static void purge();
136
137 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
138 MetaspaceObj::Type type, Metaspace::MetadataType mdtype, TRAPS);
139
140 static void print_compressed_class_space(outputStream* st) NOT_LP64({});
141
142 // Return TRUE only if UseCompressedClassPointers is True.
143 static bool using_class_space() {
144 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
145 }
146
147 static bool initialized();
148
149 };
150
151 // ClassLoaderMetaspace is an inbetween-object between a CLD and its MetaspaceArena(s).
152 //
153 // A CLD owns one MetaspaceArena if compressed class space is off, two if its one
154 // (one for allocations of Klass* structures from class space, one for the rest from
155 // non-class space).
156 //
157 // ClassLoaderMetaspace only exists to hide this logic from upper layers:
158 //
159 // +------+ +----------------------+ +-------------------+
160 // | CLD | ---> | ClassLoaderMetaspace | ----> | (non class) Arena |
161 // +------+ +----------------------+ | +-------------------+ allocation top
162 // | | v
163 // | + chunk -- chunk ... -- chunk
164 // |
165 // | +-------------------+
166 // +--> | (class) Arena |
167 // +-------------------+
168 // |
169 // + chunk ... chunk
170 // ^
171 // alloc top
172 //
173 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
174
175 // A reference to an outside lock, held by the CLD.
176 Mutex* const _lock;
177
178 const Metaspace::MetaspaceType _space_type;
179
180 // Arena for allocations from non-class metaspace
181 // (resp. for all allocations if -XX:-UseCompressedClassPointers).
182 metaspace::MetaspaceArena* _non_class_space_arena;
183
184 // Arena for allocations from class space
185 // (NULL if -XX:-UseCompressedClassPointers).
186 metaspace::MetaspaceArena* _class_space_arena;
187
188 Mutex* lock() const { return _lock; }
189 metaspace::MetaspaceArena* non_class_space_arena() const { return _non_class_space_arena; }
190 metaspace::MetaspaceArena* class_space_arena() const { return _class_space_arena; }
191
192 metaspace::MetaspaceArena* get_arena(bool is_class) {
193 return is_class ? class_space_arena() : non_class_space_arena();
194 }
195
196 public:
197
198 ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType space_type);
199
200 ~ClassLoaderMetaspace();
201
202 Metaspace::MetaspaceType space_type() const { return _space_type; }
203
204 // Allocate word_size words from Metaspace.
205 MetaWord* allocate(size_t word_size, Metaspace::MetadataType mdType);
206
207 // Attempt to expand the GC threshold to be good for at least another word_size words
208 // and allocate. Returns NULL if failure. Used during Metaspace GC.
209 MetaWord* expand_and_allocate(size_t word_size, Metaspace::MetadataType mdType);
210
211 // Prematurely returns a metaspace allocation to the _block_freelists
212 // because it is not needed anymore.
213 void deallocate(MetaWord* ptr, size_t word_size, bool is_class);
214
215 // Update statistics. This walks all in-use chunks.
216 void add_to_statistics(metaspace::clms_stats_t* out) const;
217
218 DEBUG_ONLY(void verify() const;)
219
220 // This only exists for JFR and jcmd VM.classloader_stats. We may want to
221 // change this. Capacity as a stat is of questionable use since it may
222 // contain committed and uncommitted areas. For now we do this to maintain
223 // backward compatibility with JFR.
224 void calculate_jfr_stats(size_t* p_used_bytes, size_t* p_capacity_bytes) const;
225
226 }; // end: ClassLoaderMetaspace
227
228
229 ////////////////// MetaspaceGC ///////////////////////
230
231 // Metaspace are deallocated when their class loader are GC'ed.
232 // This class implements a policy for inducing GC's to recover
233 // Metaspaces.
234
235 class MetaspaceGCThresholdUpdater : public AllStatic {
236 public:
237 enum Type {
238 ComputeNewSize,
239 ExpandAndAllocate,
240 Last
241 };
242
243 static const char* to_string(MetaspaceGCThresholdUpdater::Type updater) {
244 switch (updater) {
245 case ComputeNewSize:
246 return "compute_new_size";
247 case ExpandAndAllocate:
248 return "expand_and_allocate";
249 default:
250 assert(false, "Got bad updater: %d", (int) updater);
251 return NULL;
252 };
253 }
254 };
255
256 class MetaspaceGC : public AllStatic {
257
258 // The current high-water-mark for inducing a GC.
259 // When committed memory of all metaspaces reaches this value,
260 // a GC is induced and the value is increased. Size is in bytes.
261 static volatile size_t _capacity_until_GC;
262 static uint _shrink_factor;
263
264 static size_t shrink_factor() { return _shrink_factor; }
265 void set_shrink_factor(uint v) { _shrink_factor = v; }
266
267 public:
268
269 static void initialize();
270 static void post_initialize();
271
272 static size_t capacity_until_GC();
273 static bool inc_capacity_until_GC(size_t v,
274 size_t* new_cap_until_GC = NULL,
275 size_t* old_cap_until_GC = NULL,
276 bool* can_retry = NULL);
277 static size_t dec_capacity_until_GC(size_t v);
278
279 // The amount to increase the high-water-mark (_capacity_until_GC)
280 static size_t delta_capacity_until_GC(size_t bytes);
281
282 // Tells if we have can expand metaspace without hitting set limits.
283 static bool can_expand(size_t words, bool is_class);
284
285 // Returns amount that we can expand without hitting a GC,
286 // measured in words.
287 static size_t allowed_expansion();
288
289 // Calculate the new high-water mark at which to induce
290 // a GC.
291 static void compute_new_size();
292 };
293
294
295
296
297 class MetaspaceUtils : AllStatic {
298 public:
299
300 // Committed space actually in use by Metadata
301 static size_t used_words();
302 static size_t used_words(Metaspace::MetadataType mdtype);
303
304 // Space committed for Metaspace
305 static size_t committed_words();
306 static size_t committed_words(Metaspace::MetadataType mdtype);
307
308 // Space reserved for Metaspace
309 static size_t reserved_words();
310 static size_t reserved_words(Metaspace::MetadataType mdtype);
311
312 // _bytes() variants for convenience...
313 static size_t used_bytes() { return used_words() * BytesPerWord; }
314 static size_t used_bytes(Metaspace::MetadataType mdtype) { return used_words(mdtype) * BytesPerWord; }
315 static size_t committed_bytes() { return committed_words() * BytesPerWord; }
316 static size_t committed_bytes(Metaspace::MetadataType mdtype) { return committed_words(mdtype) * BytesPerWord; }
317 static size_t reserved_bytes() { return reserved_words() * BytesPerWord; }
318 static size_t reserved_bytes(Metaspace::MetadataType mdtype) { return reserved_words(mdtype) * BytesPerWord; }
319
320 // (See JDK-8251342). Implement or Consolidate.
321 static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype) {
322 return MetaspaceChunkFreeListSummary(0,0,0,0,0,0,0,0);
323 }
324
325 // Log change in used metadata.
326 static void print_metaspace_change(const metaspace::MetaspaceSizesSnapshot& pre_meta_values);
327
328 // This will print out a basic metaspace usage report but
329 // unlike print_report() is guaranteed not to lock or to walk the CLDG.
330 static void print_basic_report(outputStream* st, size_t scale = 0);
331
332 // Prints a report about the current metaspace state.
333 // Function will walk the CLDG and will lock the expand lock; if that is not
334 // convenient, use print_basic_report() instead.
335 static void print_report(outputStream* out, size_t scale = 0);
336
337 static void print_on(outputStream * out);
338
339 DEBUG_ONLY(static void verify(bool slow);)
340
341 };
342
343 #endif // SHARE_MEMORY_METASPACE_HPP