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 ChunkManagerTestAccessor;
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 ::ChunkManagerTestAccessor;
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() { return &_humongous_dictionary; }
67 const ChunkTreeDictionary* humongous_dictionary() const { return &_humongous_dictionary; }
68
69 // Size, in metaspace words, of all chunks managed by this ChunkManager
70 size_t _free_chunks_total;
71 // Number of chunks in this ChunkManager
72 size_t _free_chunks_count;
73
74 // Update counters after a chunk was added or removed removed.
75 void account_for_added_chunk(const Metachunk* c);
76 void account_for_removed_chunk(const Metachunk* c);
77
78 // Given a pointer to a chunk, attempts to merge it with neighboring
79 // free chunks to form a bigger chunk. Returns true if successful.
80 bool attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type);
81
82 // Helper for chunk merging:
83 // Given an address range with 1-n chunks which are all supposed to be
84 // free and hence currently managed by this ChunkManager, remove them
85 // from this ChunkManager and mark them as invalid.
86 // - This does not correct the occupancy map.
87 // - This does not adjust the counters in ChunkManager.
88 // - Does not adjust container count counter in containing VirtualSpaceNode.
89 // Returns number of chunks removed.
90 int remove_chunks_in_area(MetaWord* p, size_t word_size);
91
92 // Helper for chunk splitting: given a target chunk size and a larger free chunk,
93 // split up the larger chunk into n smaller chunks, at least one of which should be
94 // the target chunk of target chunk size. The smaller chunks, including the target
95 // chunk, are returned to the freelist. The pointer to the target chunk is returned.
96 // Note that this chunk is supposed to be removed from the freelist right away.
97 Metachunk* split_chunk(size_t target_chunk_word_size, Metachunk* chunk);
98
99 public:
100
101 ChunkManager(bool is_class);
102
103 // Add or delete (return) a chunk to the global freelist.
104 Metachunk* chunk_freelist_allocate(size_t word_size);
105
106 // Map a size to a list index assuming that there are lists
107 // for special, small, medium, and humongous chunks.
108 ChunkIndex list_index(size_t size);
109
110 // Map a given index to the chunk size.
111 size_t size_by_index(ChunkIndex index) const;
112
113 bool is_class() const { return _is_class; }
114
115 // Convenience accessors.
116 size_t medium_chunk_word_size() const { return size_by_index(MediumIndex); }
117 size_t small_chunk_word_size() const { return size_by_index(SmallIndex); }
118 size_t specialized_chunk_word_size() const { return size_by_index(SpecializedIndex); }
119
120 // Take a chunk from the ChunkManager. The chunk is expected to be in
121 // the chunk manager (the freelist if non-humongous, the dictionary if
122 // humongous).
123 void remove_chunk(Metachunk* chunk);
124
125 // Return a single chunk of type index to the ChunkManager.
126 void return_single_chunk(Metachunk* chunk);
127
128 // Add the simple linked list of chunks to the freelist of chunks
129 // of type index.
130 void return_chunk_list(Metachunk* chunk);
131
132 // Total of the space in the free chunks list
133 size_t free_chunks_total_words() const { return _free_chunks_total; }
134 size_t free_chunks_total_bytes() const { return free_chunks_total_words() * BytesPerWord; }
135
136 // Number of chunks in the free chunks list
137 size_t free_chunks_count() const { return _free_chunks_count; }
138
139 // Remove from a list by size. Selects list based on size of chunk.
140 Metachunk* free_chunks_get(size_t chunk_word_size);
141
142 #define index_bounds_check(index) \
143 assert(is_valid_chunktype(index), "Bad index: %d", (int) index)
144
145 size_t num_free_chunks(ChunkIndex index) const {
146 index_bounds_check(index);
147
148 if (index == HumongousIndex) {
149 return _humongous_dictionary.total_free_blocks();
150 }
151
152 ssize_t count = _free_chunks[index].count();
153 return count == -1 ? 0 : (size_t) count;
154 }
155
156 size_t size_free_chunks_in_bytes(ChunkIndex index) const {
157 index_bounds_check(index);
158
159 size_t word_size = 0;
160 if (index == HumongousIndex) {
161 word_size = _humongous_dictionary.total_size();
162 } else {
163 const size_t size_per_chunk_in_words = _free_chunks[index].size();
164 word_size = size_per_chunk_in_words * num_free_chunks(index);
165 }
166
167 return word_size * BytesPerWord;
168 }
169
170 MetaspaceChunkFreeListSummary chunk_free_list_summary() const {
171 return MetaspaceChunkFreeListSummary(num_free_chunks(SpecializedIndex),
172 num_free_chunks(SmallIndex),
173 num_free_chunks(MediumIndex),
174 num_free_chunks(HumongousIndex),
175 size_free_chunks_in_bytes(SpecializedIndex),
176 size_free_chunks_in_bytes(SmallIndex),
177 size_free_chunks_in_bytes(MediumIndex),
178 size_free_chunks_in_bytes(HumongousIndex));
179 }
180
181 #ifdef ASSERT
182 // Debug support
183 // Verify free list integrity. slow=true: verify chunk-internal integrity too.
184 void verify(bool slow) const;
185 void locked_verify(bool slow) const;
186 #endif
187
188 void locked_print_free_chunks(outputStream* st);
189
190 // Fill in current statistic values to the given statistics object.
191 void collect_statistics(ChunkManagerStatistics* out) const;
192
193 };
194
195 } // namespace metaspace
196
197
198 #endif // SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP
|
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/metaspace/chunkLevel.hpp"
30 #include "memory/metaspace/counter.hpp"
31 #include "memory/metaspace/metachunk.hpp"
32
33 namespace metaspace {
34
35 class VirtualSpaceList;
36
37
38 // class ChunkManager
39 //
40 // The ChunkManager has a central role. Callers request chunks from it.
41 // It keeps the freelists for chunks. If the freelist is exhausted it
42 // allocates new chunks from a connected VirtualSpaceList.
43 //
44 class ChunkManager : public CHeapObj<mtInternal> {
45
46 // A chunk manager is connected to a virtual space list which is used
47 // to allocate new root chunks when no free chunks are found.
48 VirtualSpaceList* const _vslist;
49
50 // Name
51 const char* const _name;
52
53 // Freelist
54 MetachunkList _chunks [chklvl::NUM_CHUNK_LEVELS];
55
56 // Total size, in words, of all chunks combined.
57 SizeCounter _total_word_size;
58
59 // Returns true if this manager contains the given chunk. Slow (walks free list) and
60 // only needed for verifications.
61 DEBUG_ONLY(bool contains_chunk(Metachunk* metachunk) const;)
62
63 // Given a chunk we are about to handout to the caller, make sure it is committed
64 // according to constants::committed_words_on_fresh_chunks.
65 // May fail if we hit the commit limit.
66 static bool commit_chunk_before_handout(Metachunk* c);
67
68 // Return a single chunk to the freelist and adjust accounting. No merge is attempted.
69 void return_chunk_simple(Metachunk* c);
70
71 // Remove the given chunk from its free list and adjust accounting.
72 void remove_chunk(Metachunk* chunk);
73
74 // Given a chunk which must be outside of a freelist and must be free, split it to
75 // meet a target level and return it. Splinters are added to the freelist.
76 Metachunk* split_chunk_and_add_splinters(Metachunk* c, chklvl_t target_level);
77
78 public:
79
80 // Creates a chunk manager with a given name (which is for debug purposes only)
81 // and an associated space list which will be used to request new chunks from
82 // (see get_chunk())
83 ChunkManager(const char* name, VirtualSpaceList* space_list);
84
85 // Get a chunk and be smart about it.
86 // - 1) Attempt to find a free chunk of exactly the pref_level level
87 // - 2) Failing that, attempt to find a chunk smaller or equal the minimal level.
88 // - 3) Failing that, attempt to find a free chunk of larger size and split it.
89 // - 4) Failing that, attempt to allocate a new chunk from the connected virtual space.
90 // - Failing that, give up and return NULL.
91 // Note: this is not guaranteed to return a *committed* chunk. The chunk manager will
92 // attempt to commit the returned chunk according to constants::committed_words_on_fresh_chunks;
93 // but this may fail if we hit a commit limit. In that case, a partly uncommitted chunk
94 // will be returned, and the commit is attempted again when we allocate from the chunk's
95 // uncommitted area. See also Metachunk::allocate.
96 Metachunk* get_chunk(chklvl_t min_level, chklvl_t pref_level);
97
98 // Return a single chunk to the ChunkManager and adjust accounting. May merge chunk
99 // with neighbors.
100 // Happens after a Classloader was unloaded and releases its metaspace chunks.
101 // !! Note: this may invalidate the chunk. Do not access the chunk after
102 // this function returns !!
103 void return_chunk(Metachunk* c);
104
105 // Uncommit payload area of free chunks. Will be called during Metaspace GC.
106 void uncommit_free_chunks();
107
108 // Run verifications. slow=true: verify chunk-internal integrity too.
109 DEBUG_ONLY(void verify(bool slow) const;)
110
111 // Returns the name of this chunk manager.
112 const char* name() const { return _name; }
113
114 // Returns number of words in all free chunks.
115 size_t total_word_size() const { return _total_word_size.get(); }
116
117
118 private:
119
120 static ChunkManager* _chunkmanager_class;
121 static ChunkManager* _chunkmanager_nonclass;
122
123 public:
124
125 static ChunkManager* chunkmanager_class() { return _chunkmanager_class; }
126 static ChunkManager* chunkmanager_nonclass() { return _chunkmanager_nonclass; }
127
128 static void initialize(ChunkManager* chunkmanager_class, ChunkManager* chunkmanager_nonclass);
129
130
131 };
132
133 } // namespace metaspace
134
135 #endif // SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP
|