metaspace.hpp revision 3602:da91efe96a93
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 59class ClassLoaderData; 60class MetaWord; 61class Mutex; 62class outputStream; 63class FreeChunk; 64template <class Chunk_t> class FreeList; 65template <class Chunk_t> class BinaryTreeDictionary; 66class 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 81class VirtualSpaceList; 82 83class 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); 133 134 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class); 135 136#ifndef PRODUCT 137 bool contains(const void *ptr) const; 138 bool contains_class(const void *ptr) const; 139#endif 140 141 void dump(outputStream* const out) const; 142 143 void print_on(outputStream* st) const; 144 // Debugging support 145 void verify(); 146}; 147 148class MetaspaceAux : AllStatic { 149 150 // Statistics for class space and data space in metaspace. 151 static size_t used_in_bytes(Metaspace::MetadataType mdtype); 152 static size_t free_in_bytes(Metaspace::MetadataType mdtype); 153 static size_t capacity_in_bytes(Metaspace::MetadataType mdtype); 154 static size_t reserved_in_bytes(Metaspace::MetadataType mdtype); 155 156 static size_t free_chunks_total(Metaspace::MetadataType mdtype); 157 static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype); 158 159 public: 160 // Total of space allocated to metadata in all Metaspaces 161 static size_t used_in_bytes() { 162 return used_in_bytes(Metaspace::ClassType) + 163 used_in_bytes(Metaspace::NonClassType); 164 } 165 166 // Total of available space in all Metaspaces 167 // Total of capacity allocated to all Metaspaces. This includes 168 // space in Metachunks not yet allocated and in the Metachunk 169 // freelist. 170 static size_t capacity_in_bytes() { 171 return capacity_in_bytes(Metaspace::ClassType) + 172 capacity_in_bytes(Metaspace::NonClassType); 173 } 174 175 // Total space reserved in all Metaspaces 176 static size_t reserved_in_bytes() { 177 return reserved_in_bytes(Metaspace::ClassType) + 178 reserved_in_bytes(Metaspace::NonClassType); 179 } 180 181 static size_t min_chunk_size(); 182 183 // Print change in used metadata. 184 static void print_metaspace_change(size_t prev_metadata_used); 185 static void print_on(outputStream * out); 186 static void print_on(outputStream * out, Metaspace::MetadataType mdtype); 187 188 static void print_waste(outputStream* out); 189 static void dump(outputStream* out); 190}; 191 192// Metaspace are deallocated when their class loader are GC'ed. 193// This class implements a policy for inducing GC's to recover 194// Metaspaces. 195 196class MetaspaceGC : AllStatic { 197 198 // The current high-water-mark for inducing a GC. When 199 // the capacity of all space in the virtual lists reaches this value, 200 // a GC is induced and the value is increased. This should be changed 201 // to the space actually used for allocations to avoid affects of 202 // fragmentation losses to partially used chunks. Size is in words. 203 static size_t _capacity_until_GC; 204 205 // After a GC is done any allocation that fails should try to expand 206 // the capacity of the Metaspaces. This flag is set during attempts 207 // to allocate in the VMGCOperation that does the GC. 208 static bool _expand_after_GC; 209 210 // For a CMS collection, signal that a concurrent collection should 211 // be started. 212 static bool _should_concurrent_collect; 213 214 static uint _shrink_factor; 215 216 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; } 217 218 static size_t shrink_factor() { return _shrink_factor; } 219 void set_shrink_factor(uint v) { _shrink_factor = v; } 220 221 public: 222 223 static size_t capacity_until_GC() { return _capacity_until_GC; } 224 static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; } 225 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; } 226 static void dec_capacity_until_GC(size_t v) { 227 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0; 228 } 229 static bool expand_after_GC() { return _expand_after_GC; } 230 static void set_expand_after_GC(bool v) { _expand_after_GC = v; } 231 232 static bool should_concurrent_collect() { return _should_concurrent_collect; } 233 static void set_should_concurrent_collect(bool v) { 234 _should_concurrent_collect = v; 235 } 236 237 // The amount to increase the high-water-mark (_capacity_until_GC) 238 static size_t delta_capacity_until_GC(size_t word_size); 239 240 // It is expected that this will be called when the current capacity 241 // has been used and a GC should be considered. 242 static bool should_expand(VirtualSpaceList* vsl, size_t word_size); 243 244 // Calculate the new high-water mark at which to induce 245 // a GC. 246 static void compute_new_size(); 247}; 248 249#endif // SHARE_VM_MEMORY_METASPACE_HPP 250