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