Tue, 08 Aug 2017 15:57:29 +0800
merge
aoqi@0 | 1 | /* |
aoqi@0 | 2 | * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. |
aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
aoqi@0 | 4 | * |
aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
aoqi@0 | 7 | * published by the Free Software Foundation. |
aoqi@0 | 8 | * |
aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
aoqi@0 | 13 | * accompanied this code). |
aoqi@0 | 14 | * |
aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
aoqi@0 | 18 | * |
aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
aoqi@0 | 21 | * questions. |
aoqi@0 | 22 | * |
aoqi@0 | 23 | */ |
aoqi@0 | 24 | |
aoqi@0 | 25 | #ifndef SHARE_VM_MEMORY_FREELIST_HPP |
aoqi@0 | 26 | #define SHARE_VM_MEMORY_FREELIST_HPP |
aoqi@0 | 27 | |
aoqi@0 | 28 | #include "gc_implementation/shared/allocationStats.hpp" |
aoqi@0 | 29 | |
aoqi@0 | 30 | class CompactibleFreeListSpace; |
aoqi@0 | 31 | |
aoqi@0 | 32 | // A class for maintaining a free list of Chunk's. The FreeList |
aoqi@0 | 33 | // maintains a the structure of the list (head, tail, etc.) plus |
aoqi@0 | 34 | // statistics for allocations from the list. The links between items |
aoqi@0 | 35 | // are not part of FreeList. The statistics are |
aoqi@0 | 36 | // used to make decisions about coalescing Chunk's when they |
aoqi@0 | 37 | // are swept during collection. |
aoqi@0 | 38 | // |
aoqi@0 | 39 | // See the corresponding .cpp file for a description of the specifics |
aoqi@0 | 40 | // for that implementation. |
aoqi@0 | 41 | |
aoqi@0 | 42 | class Mutex; |
aoqi@0 | 43 | |
aoqi@0 | 44 | template <class Chunk_t> |
aoqi@0 | 45 | class FreeList VALUE_OBJ_CLASS_SPEC { |
aoqi@0 | 46 | friend class CompactibleFreeListSpace; |
aoqi@0 | 47 | friend class VMStructs; |
aoqi@0 | 48 | |
aoqi@0 | 49 | private: |
aoqi@0 | 50 | Chunk_t* _head; // Head of list of free chunks |
aoqi@0 | 51 | Chunk_t* _tail; // Tail of list of free chunks |
aoqi@0 | 52 | size_t _size; // Size in Heap words of each chunk |
aoqi@0 | 53 | ssize_t _count; // Number of entries in list |
aoqi@0 | 54 | |
aoqi@0 | 55 | protected: |
aoqi@0 | 56 | |
aoqi@0 | 57 | #ifdef ASSERT |
aoqi@0 | 58 | Mutex* _protecting_lock; |
aoqi@0 | 59 | #endif |
aoqi@0 | 60 | |
aoqi@0 | 61 | // Asserts false if the protecting lock (if any) is not held. |
aoqi@0 | 62 | void assert_proper_lock_protection_work() const PRODUCT_RETURN; |
aoqi@0 | 63 | void assert_proper_lock_protection() const { |
aoqi@0 | 64 | #ifdef ASSERT |
aoqi@0 | 65 | if (_protecting_lock != NULL) |
aoqi@0 | 66 | assert_proper_lock_protection_work(); |
aoqi@0 | 67 | #endif |
aoqi@0 | 68 | } |
aoqi@0 | 69 | |
aoqi@0 | 70 | void increment_count() { |
aoqi@0 | 71 | _count++; |
aoqi@0 | 72 | } |
aoqi@0 | 73 | |
aoqi@0 | 74 | void decrement_count() { |
aoqi@0 | 75 | _count--; |
aoqi@0 | 76 | assert(_count >= 0, "Count should not be negative"); |
aoqi@0 | 77 | } |
aoqi@0 | 78 | |
aoqi@0 | 79 | public: |
aoqi@0 | 80 | // Constructor |
aoqi@0 | 81 | // Construct a list without any entries. |
aoqi@0 | 82 | FreeList(); |
aoqi@0 | 83 | |
aoqi@0 | 84 | // Do initialization |
aoqi@0 | 85 | void initialize(); |
aoqi@0 | 86 | |
aoqi@0 | 87 | // Reset the head, tail, and count of a free list. |
aoqi@0 | 88 | void reset(); |
aoqi@0 | 89 | |
aoqi@0 | 90 | // Declare the current free list to be protected by the given lock. |
aoqi@0 | 91 | #ifdef ASSERT |
aoqi@0 | 92 | Mutex* protecting_lock() const { return _protecting_lock; } |
aoqi@0 | 93 | void set_protecting_lock(Mutex* v) { |
aoqi@0 | 94 | _protecting_lock = v; |
aoqi@0 | 95 | } |
aoqi@0 | 96 | #endif |
aoqi@0 | 97 | |
aoqi@0 | 98 | // Accessors. |
aoqi@0 | 99 | Chunk_t* head() const { |
aoqi@0 | 100 | assert_proper_lock_protection(); |
aoqi@0 | 101 | return _head; |
aoqi@0 | 102 | } |
aoqi@0 | 103 | void set_head(Chunk_t* v) { |
aoqi@0 | 104 | assert_proper_lock_protection(); |
aoqi@0 | 105 | _head = v; |
aoqi@0 | 106 | assert(!_head || _head->size() == _size, "bad chunk size"); |
aoqi@0 | 107 | } |
aoqi@0 | 108 | // Set the head of the list and set the prev field of non-null |
aoqi@0 | 109 | // values to NULL. |
aoqi@0 | 110 | void link_head(Chunk_t* v); |
aoqi@0 | 111 | |
aoqi@0 | 112 | Chunk_t* tail() const { |
aoqi@0 | 113 | assert_proper_lock_protection(); |
aoqi@0 | 114 | return _tail; |
aoqi@0 | 115 | } |
aoqi@0 | 116 | void set_tail(Chunk_t* v) { |
aoqi@0 | 117 | assert_proper_lock_protection(); |
aoqi@0 | 118 | _tail = v; |
aoqi@0 | 119 | assert(!_tail || _tail->size() == _size, "bad chunk size"); |
aoqi@0 | 120 | } |
aoqi@0 | 121 | // Set the tail of the list and set the next field of non-null |
aoqi@0 | 122 | // values to NULL. |
aoqi@0 | 123 | void link_tail(Chunk_t* v) { |
aoqi@0 | 124 | assert_proper_lock_protection(); |
aoqi@0 | 125 | set_tail(v); |
aoqi@0 | 126 | if (v != NULL) { |
aoqi@0 | 127 | v->clear_next(); |
aoqi@0 | 128 | } |
aoqi@0 | 129 | } |
aoqi@0 | 130 | |
aoqi@0 | 131 | // No locking checks in read-accessors: lock-free reads (only) are benign. |
aoqi@0 | 132 | // Readers are expected to have the lock if they are doing work that |
aoqi@0 | 133 | // requires atomicity guarantees in sections of code. |
aoqi@0 | 134 | size_t size() const { |
aoqi@0 | 135 | return _size; |
aoqi@0 | 136 | } |
aoqi@0 | 137 | void set_size(size_t v) { |
aoqi@0 | 138 | assert_proper_lock_protection(); |
aoqi@0 | 139 | _size = v; |
aoqi@0 | 140 | } |
aoqi@0 | 141 | ssize_t count() const { return _count; } |
aoqi@0 | 142 | void set_count(ssize_t v) { _count = v;} |
aoqi@0 | 143 | |
aoqi@0 | 144 | size_t get_better_size() { return size(); } |
aoqi@0 | 145 | |
aoqi@0 | 146 | size_t returned_bytes() const { ShouldNotReachHere(); return 0; } |
aoqi@0 | 147 | void set_returned_bytes(size_t v) {} |
aoqi@0 | 148 | void increment_returned_bytes_by(size_t v) {} |
aoqi@0 | 149 | |
aoqi@0 | 150 | // Unlink head of list and return it. Returns NULL if |
aoqi@0 | 151 | // the list is empty. |
aoqi@0 | 152 | Chunk_t* get_chunk_at_head(); |
aoqi@0 | 153 | |
aoqi@0 | 154 | // Remove the first "n" or "count", whichever is smaller, chunks from the |
aoqi@0 | 155 | // list, setting "fl", which is required to be empty, to point to them. |
aoqi@0 | 156 | void getFirstNChunksFromList(size_t n, FreeList<Chunk_t>* fl); |
aoqi@0 | 157 | |
aoqi@0 | 158 | // Unlink this chunk from it's free list |
aoqi@0 | 159 | void remove_chunk(Chunk_t* fc); |
aoqi@0 | 160 | |
aoqi@0 | 161 | // Add this chunk to this free list. |
aoqi@0 | 162 | void return_chunk_at_head(Chunk_t* fc); |
aoqi@0 | 163 | void return_chunk_at_tail(Chunk_t* fc); |
aoqi@0 | 164 | |
aoqi@0 | 165 | // Similar to returnChunk* but also records some diagnostic |
aoqi@0 | 166 | // information. |
aoqi@0 | 167 | void return_chunk_at_head(Chunk_t* fc, bool record_return); |
aoqi@0 | 168 | void return_chunk_at_tail(Chunk_t* fc, bool record_return); |
aoqi@0 | 169 | |
aoqi@0 | 170 | // Prepend "fl" (whose size is required to be the same as that of "this") |
aoqi@0 | 171 | // to the front of "this" list. |
aoqi@0 | 172 | void prepend(FreeList<Chunk_t>* fl); |
aoqi@0 | 173 | |
aoqi@0 | 174 | // Verify that the chunk is in the list. |
aoqi@0 | 175 | // found. Return NULL if "fc" is not found. |
aoqi@0 | 176 | bool verify_chunk_in_free_list(Chunk_t* fc) const; |
aoqi@0 | 177 | |
aoqi@0 | 178 | // Printing support |
aoqi@0 | 179 | static void print_labels_on(outputStream* st, const char* c); |
aoqi@0 | 180 | void print_on(outputStream* st, const char* c = NULL) const; |
aoqi@0 | 181 | }; |
aoqi@0 | 182 | |
aoqi@0 | 183 | #endif // SHARE_VM_MEMORY_FREELIST_HPP |