1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,301 @@
1.4 +/*
1.5 + * Copyright 2001-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +class CompactibleFreeListSpace;
1.29 +
1.30 +// A class for maintaining a free list of FreeChunk's. The FreeList
1.31 +// maintains a the structure of the list (head, tail, etc.) plus
1.32 +// statistics for allocations from the list. The links between items
1.33 +// are not part of FreeList. The statistics are
1.34 +// used to make decisions about coalescing FreeChunk's when they
1.35 +// are swept during collection.
1.36 +//
1.37 +// See the corresponding .cpp file for a description of the specifics
1.38 +// for that implementation.
1.39 +
1.40 +class Mutex;
1.41 +
1.42 +class FreeList VALUE_OBJ_CLASS_SPEC {
1.43 + friend class CompactibleFreeListSpace;
1.44 + FreeChunk* _head; // List of free chunks
1.45 + FreeChunk* _tail; // Tail of list of free chunks
1.46 + size_t _size; // Size in Heap words of each chunks
1.47 + ssize_t _count; // Number of entries in list
1.48 + size_t _hint; // next larger size list with a positive surplus
1.49 +
1.50 + AllocationStats _allocation_stats; // statistics for smart allocation
1.51 +
1.52 +#ifdef ASSERT
1.53 + Mutex* _protecting_lock;
1.54 +#endif
1.55 +
1.56 + // Asserts false if the protecting lock (if any) is not held.
1.57 + void assert_proper_lock_protection_work() const PRODUCT_RETURN;
1.58 + void assert_proper_lock_protection() const {
1.59 +#ifdef ASSERT
1.60 + if (_protecting_lock != NULL)
1.61 + assert_proper_lock_protection_work();
1.62 +#endif
1.63 + }
1.64 +
1.65 + // Initialize the allocation statistics.
1.66 + protected:
1.67 + void init_statistics();
1.68 + void set_count(ssize_t v) { _count = v;}
1.69 + void increment_count() { _count++; }
1.70 + void decrement_count() {
1.71 + _count--;
1.72 + assert(_count >= 0, "Count should not be negative"); }
1.73 +
1.74 + public:
1.75 + // Constructor
1.76 + // Construct a list without any entries.
1.77 + FreeList();
1.78 + // Construct a list with "fc" as the first (and lone) entry in the list.
1.79 + FreeList(FreeChunk* fc);
1.80 + // Construct a list which will have a FreeChunk at address "addr" and
1.81 + // of size "size" as the first (and lone) entry in the list.
1.82 + FreeList(HeapWord* addr, size_t size);
1.83 +
1.84 + // Reset the head, tail, hint, and count of a free list.
1.85 + void reset(size_t hint);
1.86 +
1.87 + // Declare the current free list to be protected by the given lock.
1.88 +#ifdef ASSERT
1.89 + void set_protecting_lock(Mutex* protecting_lock) {
1.90 + _protecting_lock = protecting_lock;
1.91 + }
1.92 +#endif
1.93 +
1.94 + // Accessors.
1.95 + FreeChunk* head() const {
1.96 + assert_proper_lock_protection();
1.97 + return _head;
1.98 + }
1.99 + void set_head(FreeChunk* v) {
1.100 + assert_proper_lock_protection();
1.101 + _head = v;
1.102 + assert(!_head || _head->size() == _size, "bad chunk size");
1.103 + }
1.104 + // Set the head of the list and set the prev field of non-null
1.105 + // values to NULL.
1.106 + void link_head(FreeChunk* v) {
1.107 + assert_proper_lock_protection();
1.108 + set_head(v);
1.109 + // If this method is not used (just set the head instead),
1.110 + // this check can be avoided.
1.111 + if (v != NULL) {
1.112 + v->linkPrev(NULL);
1.113 + }
1.114 + }
1.115 +
1.116 + FreeChunk* tail() const {
1.117 + assert_proper_lock_protection();
1.118 + return _tail;
1.119 + }
1.120 + void set_tail(FreeChunk* v) {
1.121 + assert_proper_lock_protection();
1.122 + _tail = v;
1.123 + assert(!_tail || _tail->size() == _size, "bad chunk size");
1.124 + }
1.125 + // Set the tail of the list and set the next field of non-null
1.126 + // values to NULL.
1.127 + void link_tail(FreeChunk* v) {
1.128 + assert_proper_lock_protection();
1.129 + set_tail(v);
1.130 + if (v != NULL) {
1.131 + v->clearNext();
1.132 + }
1.133 + }
1.134 +
1.135 + // No locking checks in read-accessors: lock-free reads (only) are benign.
1.136 + // Readers are expected to have the lock if they are doing work that
1.137 + // requires atomicity guarantees in sections of code.
1.138 + size_t size() const {
1.139 + return _size;
1.140 + }
1.141 + void set_size(size_t v) {
1.142 + assert_proper_lock_protection();
1.143 + _size = v;
1.144 + }
1.145 + ssize_t count() const {
1.146 + return _count;
1.147 + }
1.148 + size_t hint() const {
1.149 + return _hint;
1.150 + }
1.151 + void set_hint(size_t v) {
1.152 + assert_proper_lock_protection();
1.153 + assert(v == 0 || _size < v, "Bad hint"); _hint = v;
1.154 + }
1.155 +
1.156 + // Accessors for statistics
1.157 + AllocationStats* allocation_stats() {
1.158 + assert_proper_lock_protection();
1.159 + return &_allocation_stats;
1.160 + }
1.161 +
1.162 + ssize_t desired() const {
1.163 + return _allocation_stats.desired();
1.164 + }
1.165 + void compute_desired(float inter_sweep_current,
1.166 + float inter_sweep_estimate) {
1.167 + assert_proper_lock_protection();
1.168 + _allocation_stats.compute_desired(_count,
1.169 + inter_sweep_current,
1.170 + inter_sweep_estimate);
1.171 + }
1.172 + ssize_t coalDesired() const {
1.173 + return _allocation_stats.coalDesired();
1.174 + }
1.175 + void set_coalDesired(ssize_t v) {
1.176 + assert_proper_lock_protection();
1.177 + _allocation_stats.set_coalDesired(v);
1.178 + }
1.179 +
1.180 + ssize_t surplus() const {
1.181 + return _allocation_stats.surplus();
1.182 + }
1.183 + void set_surplus(ssize_t v) {
1.184 + assert_proper_lock_protection();
1.185 + _allocation_stats.set_surplus(v);
1.186 + }
1.187 + void increment_surplus() {
1.188 + assert_proper_lock_protection();
1.189 + _allocation_stats.increment_surplus();
1.190 + }
1.191 + void decrement_surplus() {
1.192 + assert_proper_lock_protection();
1.193 + _allocation_stats.decrement_surplus();
1.194 + }
1.195 +
1.196 + ssize_t bfrSurp() const {
1.197 + return _allocation_stats.bfrSurp();
1.198 + }
1.199 + void set_bfrSurp(ssize_t v) {
1.200 + assert_proper_lock_protection();
1.201 + _allocation_stats.set_bfrSurp(v);
1.202 + }
1.203 + ssize_t prevSweep() const {
1.204 + return _allocation_stats.prevSweep();
1.205 + }
1.206 + void set_prevSweep(ssize_t v) {
1.207 + assert_proper_lock_protection();
1.208 + _allocation_stats.set_prevSweep(v);
1.209 + }
1.210 + ssize_t beforeSweep() const {
1.211 + return _allocation_stats.beforeSweep();
1.212 + }
1.213 + void set_beforeSweep(ssize_t v) {
1.214 + assert_proper_lock_protection();
1.215 + _allocation_stats.set_beforeSweep(v);
1.216 + }
1.217 +
1.218 + ssize_t coalBirths() const {
1.219 + return _allocation_stats.coalBirths();
1.220 + }
1.221 + void set_coalBirths(ssize_t v) {
1.222 + assert_proper_lock_protection();
1.223 + _allocation_stats.set_coalBirths(v);
1.224 + }
1.225 + void increment_coalBirths() {
1.226 + assert_proper_lock_protection();
1.227 + _allocation_stats.increment_coalBirths();
1.228 + }
1.229 +
1.230 + ssize_t coalDeaths() const {
1.231 + return _allocation_stats.coalDeaths();
1.232 + }
1.233 + void set_coalDeaths(ssize_t v) {
1.234 + assert_proper_lock_protection();
1.235 + _allocation_stats.set_coalDeaths(v);
1.236 + }
1.237 + void increment_coalDeaths() {
1.238 + assert_proper_lock_protection();
1.239 + _allocation_stats.increment_coalDeaths();
1.240 + }
1.241 +
1.242 + ssize_t splitBirths() const {
1.243 + return _allocation_stats.splitBirths();
1.244 + }
1.245 + void set_splitBirths(ssize_t v) {
1.246 + assert_proper_lock_protection();
1.247 + _allocation_stats.set_splitBirths(v);
1.248 + }
1.249 + void increment_splitBirths() {
1.250 + assert_proper_lock_protection();
1.251 + _allocation_stats.increment_splitBirths();
1.252 + }
1.253 +
1.254 + ssize_t splitDeaths() const {
1.255 + return _allocation_stats.splitDeaths();
1.256 + }
1.257 + void set_splitDeaths(ssize_t v) {
1.258 + assert_proper_lock_protection();
1.259 + _allocation_stats.set_splitDeaths(v);
1.260 + }
1.261 + void increment_splitDeaths() {
1.262 + assert_proper_lock_protection();
1.263 + _allocation_stats.increment_splitDeaths();
1.264 + }
1.265 +
1.266 + NOT_PRODUCT(
1.267 + // For debugging. The "_returnedBytes" in all the lists are summed
1.268 + // and compared with the total number of bytes swept during a
1.269 + // collection.
1.270 + size_t returnedBytes() const { return _allocation_stats.returnedBytes(); }
1.271 + void set_returnedBytes(size_t v) { _allocation_stats.set_returnedBytes(v); }
1.272 + void increment_returnedBytes_by(size_t v) {
1.273 + _allocation_stats.set_returnedBytes(_allocation_stats.returnedBytes() + v);
1.274 + }
1.275 + )
1.276 +
1.277 + // Unlink head of list and return it. Returns NULL if
1.278 + // the list is empty.
1.279 + FreeChunk* getChunkAtHead();
1.280 +
1.281 + // Remove the first "n" or "count", whichever is smaller, chunks from the
1.282 + // list, setting "fl", which is required to be empty, to point to them.
1.283 + void getFirstNChunksFromList(size_t n, FreeList* fl);
1.284 +
1.285 + // Unlink this chunk from it's free list
1.286 + void removeChunk(FreeChunk* fc);
1.287 +
1.288 + // Add this chunk to this free list.
1.289 + void returnChunkAtHead(FreeChunk* fc);
1.290 + void returnChunkAtTail(FreeChunk* fc);
1.291 +
1.292 + // Similar to returnChunk* but also records some diagnostic
1.293 + // information.
1.294 + void returnChunkAtHead(FreeChunk* fc, bool record_return);
1.295 + void returnChunkAtTail(FreeChunk* fc, bool record_return);
1.296 +
1.297 + // Prepend "fl" (whose size is required to be the same as that of "this")
1.298 + // to the front of "this" list.
1.299 + void prepend(FreeList* fl);
1.300 +
1.301 + // Verify that the chunk is in the list.
1.302 + // found. Return NULL if "fc" is not found.
1.303 + bool verifyChunkInFreeLists(FreeChunk* fc) const;
1.304 +};
