1 /* 2 * Copyright (c) 2011, 2012, 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 #ifndef SHARE_VM_MEMORY_METASPACE_HPP 25 #define SHARE_VM_MEMORY_METASPACE_HPP 26 27 #include "memory/allocation.hpp" 28 #include "memory/memRegion.hpp" 29 #include "runtime/virtualspace.hpp" 30 #include "utilities/exceptions.hpp" 31 32 // Metaspace 33 // 34 // Metaspaces are Arenas for the VM's metadata. 35 // They are allocated one per class loader object, and one for the null 36 // bootstrap class loader 37 // Eventually for bootstrap loader we'll have a read-only section and read-write 38 // to write for DumpSharedSpaces and read for UseSharedSpaces 39 // 40 // block X ---+ +-------------------+ 41 // | | Virtualspace | 42 // | | | 43 // | | | 44 // | |-------------------| 45 // | || Chunk | 46 // | || | 47 // | ||---------- | 48 // +------>||| block 0 | | 49 // ||---------- | 50 // ||| block 1 | | 51 // ||---------- | 52 // || | 53 // |-------------------| 54 // | | 55 // | | 56 // +-------------------+ 57 // 58 59 class ClassLoaderData; 60 class MetaWord; 61 class Mutex; 62 class outputStream; 63 class FreeChunk; 64 template <class Chunk_t> class FreeList; 65 template <class Chunk_t> class BinaryTreeDictionary; 66 class SpaceManager; 67 68 // Metaspaces each have a SpaceManager and allocations 69 // are done by the SpaceManager. Allocations are done 70 // out of the current Metachunk. When the current Metachunk 71 // is exhausted, the SpaceManager gets a new one from 72 // the current VirtualSpace. When the VirtualSpace is exhausted 73 // the SpaceManager gets a new one. The SpaceManager 74 // also manages freelists of available Chunks. 75 // 76 // Currently the space manager maintains the list of 77 // virtual spaces and the list of chunks in use. Its 78 // allocate() method returns a block for use as a 79 // quantum of metadata. 80 81 class VirtualSpaceList; 82 83 class Metaspace : public CHeapObj<mtClass> { 84 friend class VMStructs; 85 friend class SpaceManager; 86 friend class VM_CollectForMetadataAllocation; 87 friend class MetaspaceGC; 88 friend class MetaspaceAux; 89 90 public: 91 enum MetadataType {ClassType, NonClassType}; 92 93 private: 94 void initialize(Mutex* lock, size_t initial_size = 0); 95 96 static size_t _first_chunk_word_size; 97 98 SpaceManager* _vsm; 99 SpaceManager* vsm() const { return _vsm; } 100 101 SpaceManager* _class_vsm; 102 SpaceManager* class_vsm() const { return _class_vsm; } 103 104 MetaWord* allocate(size_t word_size, MetadataType mdtype); 105 106 // Virtual Space lists for both classes and other metadata 107 static VirtualSpaceList* _space_list; 108 static VirtualSpaceList* _class_space_list; 109 110 static VirtualSpaceList* space_list() { return _space_list; } 111 static VirtualSpaceList* class_space_list() { return _class_space_list; } 112 113 public: 114 115 Metaspace(Mutex* lock, size_t initial_size); 116 Metaspace(Mutex* lock); 117 ~Metaspace(); 118 119 // Initialize globals for Metaspace 120 static void global_initialize(); 121 static void initialize_class_space(ReservedSpace rs); 122 123 static size_t first_chunk_word_size() { return _first_chunk_word_size; } 124 125 char* bottom() const; 126 size_t used_words(MetadataType mdtype) const; 127 size_t free_words(MetadataType mdtype) const; 128 size_t capacity_words(MetadataType mdtype) const; 129 size_t waste_words(MetadataType mdtype) const; 130 131 static MetaWord* allocate(ClassLoaderData* loader_data, size_t size, 132 bool read_only, MetadataType mdtype, TRAPS); 133 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class); 134 135 MetaWord* expand_and_allocate(size_t size, 136 MetadataType mdtype); 137 138 #ifndef PRODUCT 139 bool contains(const void *ptr) const; 140 bool contains_class(const void *ptr) const; 141 #endif 142 143 void dump(outputStream* const out) const; 144 145 void print_on(outputStream* st) const; 146 // Debugging support 147 void verify(); 148 }; 149 150 class MetaspaceAux : AllStatic { 151 152 // Statistics for class space and data space in metaspace. 153 static size_t used_in_bytes(Metaspace::MetadataType mdtype); 154 static size_t free_in_bytes(Metaspace::MetadataType mdtype); 155 static size_t capacity_in_bytes(Metaspace::MetadataType mdtype); 156 static size_t reserved_in_bytes(Metaspace::MetadataType mdtype); 157 158 static size_t free_chunks_total(Metaspace::MetadataType mdtype); 159 static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype); 160 161 public: 162 // Total of space allocated to metadata in all Metaspaces 163 static size_t used_in_bytes() { 164 return used_in_bytes(Metaspace::ClassType) + 165 used_in_bytes(Metaspace::NonClassType); 166 } 167 168 // Total of available space in all Metaspaces 169 // Total of capacity allocated to all Metaspaces. This includes 170 // space in Metachunks not yet allocated and in the Metachunk 171 // freelist. 172 static size_t capacity_in_bytes() { 173 return capacity_in_bytes(Metaspace::ClassType) + 174 capacity_in_bytes(Metaspace::NonClassType); 175 } 176 177 // Total space reserved in all Metaspaces 178 static size_t reserved_in_bytes() { 179 return reserved_in_bytes(Metaspace::ClassType) + 180 reserved_in_bytes(Metaspace::NonClassType); 181 } 182 183 static size_t min_chunk_size(); 184 185 // Print change in used metadata. 186 static void print_metaspace_change(size_t prev_metadata_used); 187 static void print_on(outputStream * out); 188 static void print_on(outputStream * out, Metaspace::MetadataType mdtype); 189 190 static void print_waste(outputStream* out); 191 static void dump(outputStream* out); 192 }; 193 194 // Metaspace are deallocated when their class loader are GC'ed. 195 // This class implements a policy for inducing GC's to recover 196 // Metaspaces. 197 198 class MetaspaceGC : AllStatic { 199 200 // The current high-water-mark for inducing a GC. When 201 // the capacity of all space in the virtual lists reaches this value, 202 // a GC is induced and the value is increased. This should be changed 203 // to the space actually used for allocations to avoid affects of 204 // fragmentation losses to partially used chunks. Size is in words. 205 static size_t _capacity_until_GC; 206 207 // After a GC is done any allocation that fails should try to expand 208 // the capacity of the Metaspaces. This flag is set during attempts 209 // to allocate in the VMGCOperation that does the GC. 210 static bool _expand_after_GC; 211 212 // For a CMS collection, signal that a concurrent collection should 213 // be started. 214 static bool _should_concurrent_collect; 215 216 static uint _shrink_factor; 217 218 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; } 219 220 static size_t shrink_factor() { return _shrink_factor; } 221 void set_shrink_factor(uint v) { _shrink_factor = v; } 222 223 public: 224 225 static size_t capacity_until_GC() { return _capacity_until_GC; } 226 static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; } 227 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; } 228 static void dec_capacity_until_GC(size_t v) { 229 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0; 230 } 231 static bool expand_after_GC() { return _expand_after_GC; } 232 static void set_expand_after_GC(bool v) { _expand_after_GC = v; } 233 234 static bool should_concurrent_collect() { return _should_concurrent_collect; } 235 static void set_should_concurrent_collect(bool v) { 236 _should_concurrent_collect = v; 237 } 238 239 // The amount to increase the high-water-mark (_capacity_until_GC) 240 static size_t delta_capacity_until_GC(size_t word_size); 241 242 // It is expected that this will be called when the current capacity 243 // has been used and a GC should be considered. 244 static bool should_expand(VirtualSpaceList* vsl, size_t word_size); 245 246 // Calculate the new high-water mark at which to induce 247 // a GC. 248 static void compute_new_size(); 249 }; 250 251 #endif // SHARE_VM_MEMORY_METASPACE_HPP