1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/freeList.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,183 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_MEMORY_FREELIST_HPP
1.29 +#define SHARE_VM_MEMORY_FREELIST_HPP
1.30 +
1.31 +#include "gc_implementation/shared/allocationStats.hpp"
1.32 +
1.33 +class CompactibleFreeListSpace;
1.34 +
1.35 +// A class for maintaining a free list of Chunk's. The FreeList
1.36 +// maintains a the structure of the list (head, tail, etc.) plus
1.37 +// statistics for allocations from the list. The links between items
1.38 +// are not part of FreeList. The statistics are
1.39 +// used to make decisions about coalescing Chunk's when they
1.40 +// are swept during collection.
1.41 +//
1.42 +// See the corresponding .cpp file for a description of the specifics
1.43 +// for that implementation.
1.44 +
1.45 +class Mutex;
1.46 +
1.47 +template <class Chunk_t>
1.48 +class FreeList VALUE_OBJ_CLASS_SPEC {
1.49 + friend class CompactibleFreeListSpace;
1.50 + friend class VMStructs;
1.51 +
1.52 + private:
1.53 + Chunk_t* _head; // Head of list of free chunks
1.54 + Chunk_t* _tail; // Tail of list of free chunks
1.55 + size_t _size; // Size in Heap words of each chunk
1.56 + ssize_t _count; // Number of entries in list
1.57 +
1.58 + protected:
1.59 +
1.60 +#ifdef ASSERT
1.61 + Mutex* _protecting_lock;
1.62 +#endif
1.63 +
1.64 + // Asserts false if the protecting lock (if any) is not held.
1.65 + void assert_proper_lock_protection_work() const PRODUCT_RETURN;
1.66 + void assert_proper_lock_protection() const {
1.67 +#ifdef ASSERT
1.68 + if (_protecting_lock != NULL)
1.69 + assert_proper_lock_protection_work();
1.70 +#endif
1.71 + }
1.72 +
1.73 + void increment_count() {
1.74 + _count++;
1.75 + }
1.76 +
1.77 + void decrement_count() {
1.78 + _count--;
1.79 + assert(_count >= 0, "Count should not be negative");
1.80 + }
1.81 +
1.82 + public:
1.83 + // Constructor
1.84 + // Construct a list without any entries.
1.85 + FreeList();
1.86 +
1.87 + // Do initialization
1.88 + void initialize();
1.89 +
1.90 + // Reset the head, tail, and count of a free list.
1.91 + void reset();
1.92 +
1.93 + // Declare the current free list to be protected by the given lock.
1.94 +#ifdef ASSERT
1.95 + Mutex* protecting_lock() const { return _protecting_lock; }
1.96 + void set_protecting_lock(Mutex* v) {
1.97 + _protecting_lock = v;
1.98 + }
1.99 +#endif
1.100 +
1.101 + // Accessors.
1.102 + Chunk_t* head() const {
1.103 + assert_proper_lock_protection();
1.104 + return _head;
1.105 + }
1.106 + void set_head(Chunk_t* v) {
1.107 + assert_proper_lock_protection();
1.108 + _head = v;
1.109 + assert(!_head || _head->size() == _size, "bad chunk size");
1.110 + }
1.111 + // Set the head of the list and set the prev field of non-null
1.112 + // values to NULL.
1.113 + void link_head(Chunk_t* v);
1.114 +
1.115 + Chunk_t* tail() const {
1.116 + assert_proper_lock_protection();
1.117 + return _tail;
1.118 + }
1.119 + void set_tail(Chunk_t* v) {
1.120 + assert_proper_lock_protection();
1.121 + _tail = v;
1.122 + assert(!_tail || _tail->size() == _size, "bad chunk size");
1.123 + }
1.124 + // Set the tail of the list and set the next field of non-null
1.125 + // values to NULL.
1.126 + void link_tail(Chunk_t* v) {
1.127 + assert_proper_lock_protection();
1.128 + set_tail(v);
1.129 + if (v != NULL) {
1.130 + v->clear_next();
1.131 + }
1.132 + }
1.133 +
1.134 + // No locking checks in read-accessors: lock-free reads (only) are benign.
1.135 + // Readers are expected to have the lock if they are doing work that
1.136 + // requires atomicity guarantees in sections of code.
1.137 + size_t size() const {
1.138 + return _size;
1.139 + }
1.140 + void set_size(size_t v) {
1.141 + assert_proper_lock_protection();
1.142 + _size = v;
1.143 + }
1.144 + ssize_t count() const { return _count; }
1.145 + void set_count(ssize_t v) { _count = v;}
1.146 +
1.147 + size_t get_better_size() { return size(); }
1.148 +
1.149 + size_t returned_bytes() const { ShouldNotReachHere(); return 0; }
1.150 + void set_returned_bytes(size_t v) {}
1.151 + void increment_returned_bytes_by(size_t v) {}
1.152 +
1.153 + // Unlink head of list and return it. Returns NULL if
1.154 + // the list is empty.
1.155 + Chunk_t* get_chunk_at_head();
1.156 +
1.157 + // Remove the first "n" or "count", whichever is smaller, chunks from the
1.158 + // list, setting "fl", which is required to be empty, to point to them.
1.159 + void getFirstNChunksFromList(size_t n, FreeList<Chunk_t>* fl);
1.160 +
1.161 + // Unlink this chunk from it's free list
1.162 + void remove_chunk(Chunk_t* fc);
1.163 +
1.164 + // Add this chunk to this free list.
1.165 + void return_chunk_at_head(Chunk_t* fc);
1.166 + void return_chunk_at_tail(Chunk_t* fc);
1.167 +
1.168 + // Similar to returnChunk* but also records some diagnostic
1.169 + // information.
1.170 + void return_chunk_at_head(Chunk_t* fc, bool record_return);
1.171 + void return_chunk_at_tail(Chunk_t* fc, bool record_return);
1.172 +
1.173 + // Prepend "fl" (whose size is required to be the same as that of "this")
1.174 + // to the front of "this" list.
1.175 + void prepend(FreeList<Chunk_t>* fl);
1.176 +
1.177 + // Verify that the chunk is in the list.
1.178 + // found. Return NULL if "fc" is not found.
1.179 + bool verify_chunk_in_free_list(Chunk_t* fc) const;
1.180 +
1.181 + // Printing support
1.182 + static void print_labels_on(outputStream* st, const char* c);
1.183 + void print_on(outputStream* st, const char* c = NULL) const;
1.184 +};
1.185 +
1.186 +#endif // SHARE_VM_MEMORY_FREELIST_HPP
