1 /*
   2  * Copyright (c) 2018, 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_CHUNKMANAGER_HPP
  26 #define SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/binaryTreeDictionary.hpp"
  30 #include "memory/freeList.hpp"
  31 #include "memory/metaspace/metachunk.hpp"
  32 #include "memory/metaspace/metaspaceStatistics.hpp"
  33 #include "memory/metaspaceChunkFreeListSummary.hpp"
  34 #include "utilities/globalDefinitions.hpp"
  35 
  36 class ChunkManagerTest;
  37 
  38 namespace metaspace {
  39 
  40 typedef class FreeList<Metachunk> ChunkList;
  41 typedef BinaryTreeDictionary<Metachunk, FreeList<Metachunk> > ChunkTreeDictionary;
  42 
  43 // Manages the global free lists of chunks.
  44 class ChunkManager : public CHeapObj<mtInternal> {
  45   friend class ::ChunkManagerTest;
  46 
  47   // Free list of chunks of different sizes.
  48   //   SpecializedChunk
  49   //   SmallChunk
  50   //   MediumChunk
  51   ChunkList _free_chunks[NumberOfFreeLists];
  52 
  53   // Whether or not this is the class chunkmanager.
  54   const bool _is_class;
  55 
  56   // Return non-humongous chunk list by its index.
  57   ChunkList* free_chunks(ChunkIndex index);
  58 
  59   // Returns non-humongous chunk list for the given chunk word size.
  60   ChunkList* find_free_chunks_list(size_t word_size);
  61 
  62   //   HumongousChunk
  63   ChunkTreeDictionary _humongous_dictionary;
  64 
  65   // Returns the humongous chunk dictionary.
  66   ChunkTreeDictionary* humongous_dictionary() {
  67     return &_humongous_dictionary;
  68   }
  69 
  70   // Size, in metaspace words, of all chunks managed by this ChunkManager
  71   size_t _free_chunks_total;
  72   // Number of chunks in this ChunkManager
  73   size_t _free_chunks_count;
  74 
  75   // Update counters after a chunk was added or removed removed.
  76   void account_for_added_chunk(const Metachunk* c);
  77   void account_for_removed_chunk(const Metachunk* c);
  78 
  79   size_t sum_free_chunks();
  80   size_t sum_free_chunks_count();
  81 
  82   void locked_verify_free_chunks_total();
  83   void slow_locked_verify_free_chunks_total() {
  84     if (VerifyMetaspace) {
  85       locked_verify_free_chunks_total();
  86     }
  87   }
  88   void locked_verify_free_chunks_count();
  89   void slow_locked_verify_free_chunks_count() {
  90     if (VerifyMetaspace) {
  91       locked_verify_free_chunks_count();
  92     }
  93   }
  94 
  95   // Given a pointer to a chunk, attempts to merge it with neighboring
  96   // free chunks to form a bigger chunk. Returns true if successful.
  97   bool attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type);
  98 
  99   // Helper for chunk merging:
 100   //  Given an address range with 1-n chunks which are all supposed to be
 101   //  free and hence currently managed by this ChunkManager, remove them
 102   //  from this ChunkManager and mark them as invalid.
 103   // - This does not correct the occupancy map.
 104   // - This does not adjust the counters in ChunkManager.
 105   // - Does not adjust container count counter in containing VirtualSpaceNode.
 106   // Returns number of chunks removed.
 107   int remove_chunks_in_area(MetaWord* p, size_t word_size);
 108 
 109   // Helper for chunk splitting: given a target chunk size and a larger free chunk,
 110   // split up the larger chunk into n smaller chunks, at least one of which should be
 111   // the target chunk of target chunk size. The smaller chunks, including the target
 112   // chunk, are returned to the freelist. The pointer to the target chunk is returned.
 113   // Note that this chunk is supposed to be removed from the freelist right away.
 114   Metachunk* split_chunk(size_t target_chunk_word_size, Metachunk* chunk);
 115 
 116  public:
 117 
 118   ChunkManager(bool is_class);
 119 
 120   // Add or delete (return) a chunk to the global freelist.
 121   Metachunk* chunk_freelist_allocate(size_t word_size);
 122 
 123   // Map a size to a list index assuming that there are lists
 124   // for special, small, medium, and humongous chunks.
 125   ChunkIndex list_index(size_t size);
 126 
 127   // Map a given index to the chunk size.
 128   size_t size_by_index(ChunkIndex index) const;
 129 
 130   bool is_class() const { return _is_class; }
 131 
 132   // Convenience accessors.
 133   size_t medium_chunk_word_size() const { return size_by_index(MediumIndex); }
 134   size_t small_chunk_word_size() const { return size_by_index(SmallIndex); }
 135   size_t specialized_chunk_word_size() const { return size_by_index(SpecializedIndex); }
 136 
 137   // Take a chunk from the ChunkManager. The chunk is expected to be in
 138   // the chunk manager (the freelist if non-humongous, the dictionary if
 139   // humongous).
 140   void remove_chunk(Metachunk* chunk);
 141 
 142   // Return a single chunk of type index to the ChunkManager.
 143   void return_single_chunk(Metachunk* chunk);
 144 
 145   // Add the simple linked list of chunks to the freelist of chunks
 146   // of type index.
 147   void return_chunk_list(Metachunk* chunk);
 148 
 149   // Total of the space in the free chunks list
 150   size_t free_chunks_total_words();
 151   size_t free_chunks_total_bytes();
 152 
 153   // Number of chunks in the free chunks list
 154   size_t free_chunks_count();
 155 
 156   // Remove from a list by size.  Selects list based on size of chunk.
 157   Metachunk* free_chunks_get(size_t chunk_word_size);
 158 
 159 #define index_bounds_check(index)                                         \
 160   assert(is_valid_chunktype(index), "Bad index: %d", (int) index)
 161 
 162   size_t num_free_chunks(ChunkIndex index) const {
 163     index_bounds_check(index);
 164 
 165     if (index == HumongousIndex) {
 166       return _humongous_dictionary.total_free_blocks();
 167     }
 168 
 169     ssize_t count = _free_chunks[index].count();
 170     return count == -1 ? 0 : (size_t) count;
 171   }
 172 
 173   size_t size_free_chunks_in_bytes(ChunkIndex index) const {
 174     index_bounds_check(index);
 175 
 176     size_t word_size = 0;
 177     if (index == HumongousIndex) {
 178       word_size = _humongous_dictionary.total_size();
 179     } else {
 180       const size_t size_per_chunk_in_words = _free_chunks[index].size();
 181       word_size = size_per_chunk_in_words * num_free_chunks(index);
 182     }
 183 
 184     return word_size * BytesPerWord;
 185   }
 186 
 187   MetaspaceChunkFreeListSummary chunk_free_list_summary() const {
 188     return MetaspaceChunkFreeListSummary(num_free_chunks(SpecializedIndex),
 189                                          num_free_chunks(SmallIndex),
 190                                          num_free_chunks(MediumIndex),
 191                                          num_free_chunks(HumongousIndex),
 192                                          size_free_chunks_in_bytes(SpecializedIndex),
 193                                          size_free_chunks_in_bytes(SmallIndex),
 194                                          size_free_chunks_in_bytes(MediumIndex),
 195                                          size_free_chunks_in_bytes(HumongousIndex));
 196   }
 197 
 198   // Debug support
 199   void verify();
 200   void slow_verify() {
 201     if (VerifyMetaspace) {
 202       verify();
 203     }
 204   }
 205   void locked_verify();
 206   void slow_locked_verify() {
 207     if (VerifyMetaspace) {
 208       locked_verify();
 209     }
 210   }
 211 
 212   void locked_print_free_chunks(outputStream* st);
 213   void locked_print_sum_free_chunks(outputStream* st);
 214 
 215   // Fill in current statistic values to the given statistics object.
 216   void collect_statistics(ChunkManagerStatistics* out) const;
 217 
 218 };
 219 
 220 } // namespace metaspace
 221 
 222 
 223 #endif /* SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP_ */
 224