rev 57380 : [mq]: metaspace-improvement
1 /* 2 * Copyright (c) 2018, 2019, 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 25 #ifndef SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP 26 #define SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP 27 28 #include "memory/metaspace/constants.hpp" 29 #include "memory/metaspace/counter.hpp" 30 #include "memory/metaspace/chunkTree.hpp" 31 #include "memory/metaspace/commitMask.hpp" 32 #include "memory/virtualspace.hpp" 33 #include "memory/memRegion.hpp" 34 #include "utilities/debug.hpp" 35 #include "utilities/bitMap.hpp" 36 #include "utilities/globalDefinitions.hpp" 37 38 39 class outputStream; 40 41 namespace metaspace { 42 43 class CommitLimiter; 44 45 // VirtualSpaceNode manage a single address range of the Metaspace. 46 // 47 // That address range may contain interleaved committed and uncommitted 48 // regions. It keeps track of which regions have committed and offers 49 // functions to commit and uncommit regions. 50 // 51 // It allocates and hands out memory ranges, starting at the bottom. 52 // 53 // Address range must be aligned to root chunk size. 54 // 55 class VirtualSpaceNode : public CHeapObj<mtClass> { 56 57 // Link to next VirtualSpaceNode 58 VirtualSpaceNode* _next; 59 60 ReservedSpace _rs; 61 62 // Start pointer of the area. 63 MetaWord* const _base; 64 65 // Size, in words, of the whole node 66 const size_t _word_size; 67 68 // Size, in words, of the range of this node which has been handed out in 69 // the form of chunks. 70 size_t _used_words; 71 72 // The bitmap describing the commit state of the region: 73 // Each bit covers a region of 64K (see constants::commit_granule_size). 74 CommitMask _commit_mask; 75 76 // An array of chunk trees. Each one describes fragmentation inside the associated root chunk. 77 ChunkTreeArray _chunk_tree_array; 78 79 // Limiter object to ask before expanding the committed size of this node. 80 CommitLimiter* const _commit_limiter; 81 82 // Points to outside size counters which we are to increase/decrease when we commit/uncommit 83 // space from this node. 84 SizeCounter* const _total_reserved_words_counter; 85 SizeCounter* const _total_committed_words_counter; 86 87 /// committing, uncommitting /// 88 89 // Given a pointer into this node, calculate the start of the commit granule 90 // the pointer points into. 91 MetaWord* calc_start_of_granule(MetaWord* p) const { 92 DEBUG_ONLY(check_pointer(p)); 93 return align_down(p, constants::commit_granule_bytes); 94 } 95 96 // Given an address range, ensure it is committed. 97 // 98 // The range has to be aligned to granule size. 99 // 100 // Function will: 101 // - check how many granules in that region are uncommitted; If all are committed, it 102 // returns true immediately. 103 // - check if committing those uncommitted granules would bring us over the commit limit 104 // (GC threshold, MaxMetaspaceSize). If true, it returns false. 105 // - commit the memory. 106 // - mark the range as committed in the commit mask 107 // 108 // Returns true if success, false if it did hit a commit limit. 109 bool commit_range(MetaWord* p, size_t word_size); 110 111 //// creation //// 112 113 // Create a new empty node spanning the given reserved space. 114 VirtualSpaceNode(ReservedSpace rs, 115 CommitLimiter* limiter, 116 SizeCounter* reserve_counter, 117 SizeCounter* commit_counter); 118 119 MetaWord* base() const { return _base; } 120 MetaWord* word_size() const { return _word_size; } 121 122 public: 123 124 // Create a node of a given size 125 static VirtualSpaceNode* create_node(size_t word_size, 126 CommitLimiter* limiter, 127 SizeCounter* reserve_counter, 128 SizeCounter* commit_counter); 129 130 // Create a node over an existing space 131 static VirtualSpaceNode* create_node(ReservedSpace rs, 132 CommitLimiter* limiter, 133 SizeCounter* reserve_counter, 134 SizeCounter* commit_counter); 135 136 ~VirtualSpaceNode(); 137 138 //// Chunk allocation, splitting, merging ///// 139 140 // Allocate a root chunk from this node. Will fail and return NULL 141 // if the node is full. 142 // Note: this just returns a chunk whose memory is reserved; no memory is committed yet. 143 // Hence, before using this chunk, it must be committed. 144 // Also, no limits are checked, since no committing takes place. 145 Metachunk* allocate_root_chunk(); 146 147 // Given a chunk c, split it recursively until you get a chunk of the given target_level. 148 // 149 // The original chunk must not be part of a freelist. 150 // 151 // Returns pointer to the result chunk; returns split off chunks in splinters array. 152 // 153 // Returns NULL if chunk cannot be split at least once. 154 Metachunk* split(chklvl_t target_level, Metachunk* c, Metachunk* splinters[chklvl::NUM_CHUNK_LEVELS]); 155 156 // Given a chunk, attempt to merge it recursively with its neighboring chunks. 157 // 158 // If successful (merged at least once), returns address of 159 // the merged chunk; NULL otherwise. 160 // 161 // The merged chunks are removed from their freelist; the number of merged chunks is 162 // returned, split by level, in num_merged array. Note that these numbers does not 163 // include the original chunk. 164 // 165 // !!! Please note that if this method returns a non-NULL value, the 166 // original chunk will be invalid and should not be accessed anymore! !!! 167 Metachunk* merge(Metachunk* c, int num_merged[chklvl::NUM_CHUNK_LEVELS]); 168 169 170 /// misc ///// 171 172 // Returns size, in words, of the used space in this node alone. 173 // (Notes: 174 // - This is the space handed out to the ChunkManager, so it is "used" from the viewpoint of this node, 175 // but not necessarily used for Metadata. 176 // - This may or may not be committed memory. 177 size_t used_words() const { return _used_words; } 178 179 // Returns size, in words, of how much space is left in this node alone. 180 size_t free_words() const { return _word_size - _used_words; } 181 182 // Returns size, in words, of committed space in this node alone. 183 size_t committed_words() const; 184 185 //// Committing/uncommitting memory ///// 186 187 // Given an address range, ensure it is committed. 188 // 189 // The range does not have to be aligned to granule size. However, the function will always commit 190 // whole granules. 191 // 192 // Function will: 193 // - check how many granules in that region are uncommitted; If all are committed, it 194 // returns true immediately. 195 // - check if committing those uncommitted granules would bring us over the commit limit 196 // (GC threshold, MaxMetaspaceSize). If true, it returns false. 197 // - commit the memory. 198 // - mark the range as committed in the commit mask 199 // 200 // Returns true if success, false if it did hit a commit limit. 201 bool ensure_range_is_committed(MetaWord* p, size_t word_size); 202 203 // Given an address range (which has to be aligned to commit granule size): 204 // - uncommit it 205 // - mark it as uncommitted in the commit mask 206 bool uncommit_range(MetaWord* p, size_t word_size); 207 208 //// List stuff //// 209 VirtualSpaceNode* next() const { return _next; } 210 void set_next(VirtualSpaceNode* vsn) { _next = vsn; } 211 212 /// Debug stuff //// 213 214 // Verify counters and basic structure. Slow mode: verify all chunks in depth 215 bool contains(const MetaWord* p) const { 216 return p >= _base && p < _base + _used_words; 217 } 218 219 #ifdef ASSERT 220 void check_pointer(const MetaWord* p) const { 221 assert(contains(p), "invalid pointer"); 222 } 223 void verify(bool slow) const; 224 #endif 225 226 }; 227 228 229 } // namespace metaspace 230 231 #endif // SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP --- EOF ---