J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 1 | /* |
Kim Barrett | c3808b2 | 2015-12-28 13:59:20 -0500 | [diff] [blame] | 2 | * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved. |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 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 | * |
Erik Trimble | ba7c173 | 2010-05-27 19:08:38 -0700 | [diff] [blame] | 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. |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 22 | * |
| 23 | */ |
| 24 | |
Per Lidén | 4dc240f | 2015-05-13 15:16:06 +0200 | [diff] [blame] | 25 | #ifndef SHARE_VM_GC_SHARED_REFERENCEPROCESSOR_HPP |
| 26 | #define SHARE_VM_GC_SHARED_REFERENCEPROCESSOR_HPP |
Stefan Karlsson | 8006fe8 | 2010-11-23 13:22:55 -0800 | [diff] [blame] | 27 | |
Per Lidén | 4dc240f | 2015-05-13 15:16:06 +0200 | [diff] [blame] | 28 | #include "gc/shared/gcTrace.hpp" |
| 29 | #include "gc/shared/referencePolicy.hpp" |
| 30 | #include "gc/shared/referenceProcessorStats.hpp" |
Staffan Larsen | 718f325 | 2013-06-10 11:30:51 +0200 | [diff] [blame] | 31 | #include "memory/referenceType.hpp" |
Stefan Karlsson | 8006fe8 | 2010-11-23 13:22:55 -0800 | [diff] [blame] | 32 | #include "oops/instanceRefKlass.hpp" |
| 33 | |
Staffan Larsen | 718f325 | 2013-06-10 11:30:51 +0200 | [diff] [blame] | 34 | class GCTimer; |
| 35 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 36 | // ReferenceProcessor class encapsulates the per-"collector" processing |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 37 | // of java.lang.Reference objects for GC. The interface is useful for supporting |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 38 | // a generational abstraction, in particular when there are multiple |
| 39 | // generations that are being independently collected -- possibly |
| 40 | // concurrently and/or incrementally. Note, however, that the |
| 41 | // ReferenceProcessor class abstracts away from a generational setting |
| 42 | // by using only a heap interval (called "span" below), thus allowing |
| 43 | // its use in a straightforward manner in a general, non-generational |
| 44 | // setting. |
| 45 | // |
| 46 | // The basic idea is that each ReferenceProcessor object concerns |
| 47 | // itself with ("weak") reference processing in a specific "span" |
| 48 | // of the heap of interest to a specific collector. Currently, |
| 49 | // the span is a convex interval of the heap, but, efficiency |
| 50 | // apart, there seems to be no reason it couldn't be extended |
| 51 | // (with appropriate modifications) to any "non-convex interval". |
| 52 | |
| 53 | // forward references |
| 54 | class ReferencePolicy; |
| 55 | class AbstractRefProcTaskExecutor; |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 56 | |
| 57 | // List of discovered references. |
| 58 | class DiscoveredList { |
| 59 | public: |
| 60 | DiscoveredList() : _len(0), _compressed_head(0), _oop_head(NULL) { } |
Goetz Lindenmaier | 6397e80 | 2016-01-18 10:25:41 +0100 | [diff] [blame] | 61 | inline oop head() const; |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 62 | HeapWord* adr_head() { |
| 63 | return UseCompressedOops ? (HeapWord*)&_compressed_head : |
| 64 | (HeapWord*)&_oop_head; |
| 65 | } |
Goetz Lindenmaier | 6397e80 | 2016-01-18 10:25:41 +0100 | [diff] [blame] | 66 | inline void set_head(oop o); |
| 67 | inline bool is_empty() const; |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 68 | size_t length() { return _len; } |
| 69 | void set_length(size_t len) { _len = len; } |
| 70 | void inc_length(size_t inc) { _len += inc; assert(_len > 0, "Error"); } |
| 71 | void dec_length(size_t dec) { _len -= dec; } |
| 72 | private: |
| 73 | // Set value depending on UseCompressedOops. This could be a template class |
| 74 | // but then we have to fix all the instantiations and declarations that use this class. |
| 75 | oop _oop_head; |
| 76 | narrowOop _compressed_head; |
| 77 | size_t _len; |
| 78 | }; |
| 79 | |
| 80 | // Iterator for the list of discovered references. |
| 81 | class DiscoveredListIterator { |
| 82 | private: |
| 83 | DiscoveredList& _refs_list; |
| 84 | HeapWord* _prev_next; |
| 85 | oop _prev; |
| 86 | oop _ref; |
| 87 | HeapWord* _discovered_addr; |
| 88 | oop _next; |
| 89 | HeapWord* _referent_addr; |
| 90 | oop _referent; |
| 91 | OopClosure* _keep_alive; |
| 92 | BoolObjectClosure* _is_alive; |
| 93 | |
| 94 | DEBUG_ONLY( |
| 95 | oop _first_seen; // cyclic linked list check |
| 96 | ) |
| 97 | |
| 98 | NOT_PRODUCT( |
| 99 | size_t _processed; |
| 100 | size_t _removed; |
| 101 | ) |
| 102 | |
| 103 | public: |
| 104 | inline DiscoveredListIterator(DiscoveredList& refs_list, |
| 105 | OopClosure* keep_alive, |
Goetz Lindenmaier | 6397e80 | 2016-01-18 10:25:41 +0100 | [diff] [blame] | 106 | BoolObjectClosure* is_alive); |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 107 | |
| 108 | // End Of List. |
| 109 | inline bool has_next() const { return _ref != NULL; } |
| 110 | |
| 111 | // Get oop to the Reference object. |
| 112 | inline oop obj() const { return _ref; } |
| 113 | |
| 114 | // Get oop to the referent object. |
| 115 | inline oop referent() const { return _referent; } |
| 116 | |
| 117 | // Returns true if referent is alive. |
| 118 | inline bool is_referent_alive() const { |
| 119 | return _is_alive->do_object_b(_referent); |
| 120 | } |
| 121 | |
| 122 | // Loads data for the current reference. |
| 123 | // The "allow_null_referent" argument tells us to allow for the possibility |
| 124 | // of a NULL referent in the discovered Reference object. This typically |
| 125 | // happens in the case of concurrent collectors that may have done the |
| 126 | // discovery concurrently, or interleaved, with mutator execution. |
| 127 | void load_ptrs(DEBUG_ONLY(bool allow_null_referent)); |
| 128 | |
| 129 | // Move to the next discovered reference. |
| 130 | inline void next() { |
| 131 | _prev_next = _discovered_addr; |
| 132 | _prev = _ref; |
| 133 | move_to_next(); |
| 134 | } |
| 135 | |
| 136 | // Remove the current reference from the list |
| 137 | void remove(); |
| 138 | |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 139 | // Make the referent alive. |
| 140 | inline void make_referent_alive() { |
| 141 | if (UseCompressedOops) { |
| 142 | _keep_alive->do_oop((narrowOop*)_referent_addr); |
| 143 | } else { |
| 144 | _keep_alive->do_oop((oop*)_referent_addr); |
| 145 | } |
| 146 | } |
| 147 | |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 148 | // NULL out referent pointer. |
| 149 | void clear_referent(); |
| 150 | |
| 151 | // Statistics |
| 152 | NOT_PRODUCT( |
| 153 | inline size_t processed() const { return _processed; } |
| 154 | inline size_t removed() const { return _removed; } |
| 155 | ) |
| 156 | |
| 157 | inline void move_to_next() { |
| 158 | if (_ref == _next) { |
| 159 | // End of the list. |
| 160 | _ref = NULL; |
| 161 | } else { |
| 162 | _ref = _next; |
| 163 | } |
| 164 | assert(_ref != _first_seen, "cyclic ref_list found"); |
| 165 | NOT_PRODUCT(_processed++); |
| 166 | } |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 167 | }; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 168 | |
Zhengyu Gu | a39b176 | 2012-06-28 17:03:16 -0400 | [diff] [blame] | 169 | class ReferenceProcessor : public CHeapObj<mtGC> { |
Staffan Larsen | 718f325 | 2013-06-10 11:30:51 +0200 | [diff] [blame] | 170 | |
| 171 | private: |
| 172 | size_t total_count(DiscoveredList lists[]); |
| 173 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 174 | protected: |
John Cuthbertson | 4738ed8 | 2011-10-12 10:25:51 -0700 | [diff] [blame] | 175 | // The SoftReference master timestamp clock |
| 176 | static jlong _soft_ref_timestamp_clock; |
| 177 | |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 178 | MemRegion _span; // (right-open) interval of heap |
| 179 | // subject to wkref discovery |
| 180 | |
| 181 | bool _discovering_refs; // true when discovery enabled |
| 182 | bool _discovery_is_atomic; // if discovery is atomic wrt |
| 183 | // other collectors in configuration |
| 184 | bool _discovery_is_mt; // true if reference discovery is MT. |
| 185 | |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 186 | bool _enqueuing_is_done; // true if all weak references enqueued |
| 187 | bool _processing_is_mt; // true during phases when |
| 188 | // reference processing is MT. |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 189 | uint _next_id; // round-robin mod _num_q counter in |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 190 | // support of work distribution |
| 191 | |
| 192 | // For collectors that do not keep GC liveness information |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 193 | // in the object header, this field holds a closure that |
| 194 | // helps the reference processor determine the reachability |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 195 | // of an oop. It is currently initialized to NULL for all |
| 196 | // collectors except for CMS and G1. |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 197 | BoolObjectClosure* _is_alive_non_header; |
| 198 | |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 199 | // Soft ref clearing policies |
| 200 | // . the default policy |
| 201 | static ReferencePolicy* _default_soft_ref_policy; |
| 202 | // . the "clear all" policy |
| 203 | static ReferencePolicy* _always_clear_soft_ref_policy; |
| 204 | // . the current policy below is either one of the above |
| 205 | ReferencePolicy* _current_soft_ref_policy; |
| 206 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 207 | // The discovered ref lists themselves |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 208 | |
Jon Masamitsu | 28e56b8 | 2010-09-20 14:38:38 -0700 | [diff] [blame] | 209 | // The active MT'ness degree of the queues below |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 210 | uint _num_q; |
Jon Masamitsu | 28e56b8 | 2010-09-20 14:38:38 -0700 | [diff] [blame] | 211 | // The maximum MT'ness degree of the queues below |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 212 | uint _max_num_q; |
John Cuthbertson | cab4072 | 2011-10-17 09:57:41 -0700 | [diff] [blame] | 213 | |
| 214 | // Master array of discovered oops |
| 215 | DiscoveredList* _discovered_refs; |
| 216 | |
| 217 | // Arrays of lists of oops, one per thread (pointers into master array above) |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 218 | DiscoveredList* _discoveredSoftRefs; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 219 | DiscoveredList* _discoveredWeakRefs; |
| 220 | DiscoveredList* _discoveredFinalRefs; |
| 221 | DiscoveredList* _discoveredPhantomRefs; |
| 222 | |
| 223 | public: |
Kim Barrett | c3808b2 | 2015-12-28 13:59:20 -0500 | [diff] [blame] | 224 | static int number_of_subclasses_of_ref() { return (REF_PHANTOM - REF_OTHER); } |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 225 | |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 226 | uint num_q() { return _num_q; } |
| 227 | uint max_num_q() { return _max_num_q; } |
| 228 | void set_active_mt_degree(uint v) { _num_q = v; } |
John Cuthbertson | cab4072 | 2011-10-17 09:57:41 -0700 | [diff] [blame] | 229 | |
| 230 | DiscoveredList* discovered_refs() { return _discovered_refs; } |
John Cuthbertson | 1b62d10 | 2011-09-22 10:57:37 -0700 | [diff] [blame] | 231 | |
Y. Srinivas Ramakrishna | 16aa57c | 2008-12-01 23:25:24 -0800 | [diff] [blame] | 232 | ReferencePolicy* setup_policy(bool always_clear) { |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 233 | _current_soft_ref_policy = always_clear ? |
| 234 | _always_clear_soft_ref_policy : _default_soft_ref_policy; |
Y. Srinivas Ramakrishna | 16aa57c | 2008-12-01 23:25:24 -0800 | [diff] [blame] | 235 | _current_soft_ref_policy->setup(); // snapshot the policy threshold |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 236 | return _current_soft_ref_policy; |
| 237 | } |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 238 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 239 | // Process references with a certain reachability level. |
Bengt Rutisson | d3651ac | 2015-09-28 09:28:53 +0200 | [diff] [blame] | 240 | void process_discovered_reflist(DiscoveredList refs_lists[], |
| 241 | ReferencePolicy* policy, |
| 242 | bool clear_referent, |
| 243 | BoolObjectClosure* is_alive, |
| 244 | OopClosure* keep_alive, |
| 245 | VoidClosure* complete_gc, |
| 246 | AbstractRefProcTaskExecutor* task_executor); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 247 | |
Kim Barrett | b78e967 | 2015-09-16 16:25:02 +0200 | [diff] [blame] | 248 | void process_phaseJNI(BoolObjectClosure* is_alive, |
| 249 | OopClosure* keep_alive, |
| 250 | VoidClosure* complete_gc); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 251 | |
| 252 | // Work methods used by the method process_discovered_reflist |
| 253 | // Phase1: keep alive all those referents that are otherwise |
| 254 | // dead but which must be kept alive by policy (and their closure). |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 255 | void process_phase1(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 256 | ReferencePolicy* policy, |
| 257 | BoolObjectClosure* is_alive, |
| 258 | OopClosure* keep_alive, |
| 259 | VoidClosure* complete_gc); |
| 260 | // Phase2: remove all those references whose referents are |
| 261 | // reachable. |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 262 | inline void process_phase2(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 263 | BoolObjectClosure* is_alive, |
| 264 | OopClosure* keep_alive, |
| 265 | VoidClosure* complete_gc) { |
| 266 | if (discovery_is_atomic()) { |
| 267 | // complete_gc is ignored in this case for this phase |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 268 | pp2_work(refs_list, is_alive, keep_alive); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 269 | } else { |
| 270 | assert(complete_gc != NULL, "Error"); |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 271 | pp2_work_concurrent_discovery(refs_list, is_alive, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 272 | keep_alive, complete_gc); |
| 273 | } |
| 274 | } |
| 275 | // Work methods in support of process_phase2 |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 276 | void pp2_work(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 277 | BoolObjectClosure* is_alive, |
| 278 | OopClosure* keep_alive); |
| 279 | void pp2_work_concurrent_discovery( |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 280 | DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 281 | BoolObjectClosure* is_alive, |
| 282 | OopClosure* keep_alive, |
| 283 | VoidClosure* complete_gc); |
| 284 | // Phase3: process the referents by either clearing them |
| 285 | // or keeping them alive (and their closure) |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 286 | void process_phase3(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 287 | bool clear_referent, |
| 288 | BoolObjectClosure* is_alive, |
| 289 | OopClosure* keep_alive, |
| 290 | VoidClosure* complete_gc); |
| 291 | |
| 292 | // Enqueue references with a certain reachability level |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 293 | void enqueue_discovered_reflist(DiscoveredList& refs_list, HeapWord* pending_list_addr); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 294 | |
| 295 | // "Preclean" all the discovered reference lists |
| 296 | // by removing references with strongly reachable referents. |
| 297 | // The first argument is a predicate on an oop that indicates |
| 298 | // its (strong) reachability and the second is a closure that |
| 299 | // may be used to incrementalize or abort the precleaning process. |
| 300 | // The caller is responsible for taking care of potential |
| 301 | // interference with concurrent operations on these lists |
| 302 | // (or predicates involved) by other threads. Currently |
Jon Masamitsu | 5c58d27 | 2012-09-01 13:25:18 -0400 | [diff] [blame] | 303 | // only used by the CMS collector. |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 304 | void preclean_discovered_references(BoolObjectClosure* is_alive, |
| 305 | OopClosure* keep_alive, |
| 306 | VoidClosure* complete_gc, |
Staffan Larsen | 718f325 | 2013-06-10 11:30:51 +0200 | [diff] [blame] | 307 | YieldClosure* yield, |
Bengt Rutisson | 003892f | 2015-09-30 09:07:21 +0200 | [diff] [blame] | 308 | GCTimer* gc_timer); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 309 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 310 | // Returns the name of the discovered reference list |
| 311 | // occupying the i / _num_q slot. |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 312 | const char* list_name(uint i); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 313 | |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 314 | void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor); |
| 315 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 316 | protected: |
| 317 | // "Preclean" the given discovered reference list |
| 318 | // by removing references with strongly reachable referents. |
| 319 | // Currently used in support of CMS only. |
| 320 | void preclean_discovered_reflist(DiscoveredList& refs_list, |
| 321 | BoolObjectClosure* is_alive, |
| 322 | OopClosure* keep_alive, |
| 323 | VoidClosure* complete_gc, |
| 324 | YieldClosure* yield); |
| 325 | |
Y. Srinivas Ramakrishna | b4b287e | 2011-03-17 10:32:46 -0700 | [diff] [blame] | 326 | // round-robin mod _num_q (not: _not_ mode _max_num_q) |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 327 | uint next_id() { |
| 328 | uint id = _next_id; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 329 | if (++_next_id == _num_q) { |
| 330 | _next_id = 0; |
| 331 | } |
| 332 | return id; |
| 333 | } |
| 334 | DiscoveredList* get_discovered_list(ReferenceType rt); |
| 335 | inline void add_to_discovered_list_mt(DiscoveredList& refs_list, oop obj, |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 336 | HeapWord* discovered_addr); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 337 | |
Stefan Karlsson | 5b6ba4e | 2011-09-01 16:18:17 +0200 | [diff] [blame] | 338 | void clear_discovered_references(DiscoveredList& refs_list); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 339 | |
| 340 | // Calculate the number of jni handles. |
Bengt Rutisson | ffeb0bd | 2015-12-10 14:57:55 +0100 | [diff] [blame] | 341 | size_t count_jni_refs(); |
| 342 | |
| 343 | void log_reflist_counts(DiscoveredList ref_lists[], size_t total_count) PRODUCT_RETURN; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 344 | |
| 345 | // Balances reference queues. |
| 346 | void balance_queues(DiscoveredList ref_lists[]); |
| 347 | |
| 348 | // Update (advance) the soft ref master clock field. |
| 349 | void update_soft_ref_master_clock(); |
| 350 | |
| 351 | public: |
Y. Srinivas Ramakrishna | b4b287e | 2011-03-17 10:32:46 -0700 | [diff] [blame] | 352 | // Default parameters give you a vanilla reference processor. |
| 353 | ReferenceProcessor(MemRegion span, |
Jon Masamitsu | 0ebc10b | 2011-12-14 13:34:57 -0800 | [diff] [blame] | 354 | bool mt_processing = false, uint mt_processing_degree = 1, |
| 355 | bool mt_discovery = false, uint mt_discovery_degree = 1, |
Y. Srinivas Ramakrishna | b4b287e | 2011-03-17 10:32:46 -0700 | [diff] [blame] | 356 | bool atomic_discovery = true, |
Bengt Rutisson | 426151a | 2014-06-03 10:44:36 +0200 | [diff] [blame] | 357 | BoolObjectClosure* is_alive_non_header = NULL); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 358 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 359 | // RefDiscoveryPolicy values |
John Cuthbertson | b34027a | 2010-01-29 14:51:38 -0800 | [diff] [blame] | 360 | enum DiscoveryPolicy { |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 361 | ReferenceBasedDiscovery = 0, |
John Cuthbertson | b34027a | 2010-01-29 14:51:38 -0800 | [diff] [blame] | 362 | ReferentBasedDiscovery = 1, |
| 363 | DiscoveryPolicyMin = ReferenceBasedDiscovery, |
| 364 | DiscoveryPolicyMax = ReferentBasedDiscovery |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 365 | }; |
| 366 | |
| 367 | static void init_statics(); |
| 368 | |
| 369 | public: |
| 370 | // get and set "is_alive_non_header" field |
| 371 | BoolObjectClosure* is_alive_non_header() { |
| 372 | return _is_alive_non_header; |
| 373 | } |
| 374 | void set_is_alive_non_header(BoolObjectClosure* is_alive_non_header) { |
| 375 | _is_alive_non_header = is_alive_non_header; |
| 376 | } |
| 377 | |
| 378 | // get and set span |
| 379 | MemRegion span() { return _span; } |
| 380 | void set_span(MemRegion span) { _span = span; } |
| 381 | |
| 382 | // start and stop weak ref discovery |
Kim Barrett | 093d269 | 2014-12-17 22:32:44 -0500 | [diff] [blame] | 383 | void enable_discovery(bool check_no_refs = true); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 384 | void disable_discovery() { _discovering_refs = false; } |
| 385 | bool discovery_enabled() { return _discovering_refs; } |
| 386 | |
| 387 | // whether discovery is atomic wrt other collectors |
| 388 | bool discovery_is_atomic() const { return _discovery_is_atomic; } |
| 389 | void set_atomic_discovery(bool atomic) { _discovery_is_atomic = atomic; } |
| 390 | |
| 391 | // whether discovery is done by multiple threads same-old-timeously |
| 392 | bool discovery_is_mt() const { return _discovery_is_mt; } |
| 393 | void set_mt_discovery(bool mt) { _discovery_is_mt = mt; } |
| 394 | |
| 395 | // Whether we are in a phase when _processing_ is MT. |
| 396 | bool processing_is_mt() const { return _processing_is_mt; } |
| 397 | void set_mt_processing(bool mt) { _processing_is_mt = mt; } |
| 398 | |
Jesper Wilhelmsson | 81ba2e3 | 2014-01-23 14:47:23 +0100 | [diff] [blame] | 399 | // whether all enqueueing of weak references is complete |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 400 | bool enqueuing_is_done() { return _enqueuing_is_done; } |
| 401 | void set_enqueuing_is_done(bool v) { _enqueuing_is_done = v; } |
| 402 | |
| 403 | // iterate over oops |
| 404 | void weak_oops_do(OopClosure* f); // weak roots |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 405 | |
Jon Masamitsu | 28e56b8 | 2010-09-20 14:38:38 -0700 | [diff] [blame] | 406 | // Balance each of the discovered lists. |
| 407 | void balance_all_queues(); |
Jon Masamitsu | 5c58d27 | 2012-09-01 13:25:18 -0400 | [diff] [blame] | 408 | void verify_list(DiscoveredList& ref_list); |
Jon Masamitsu | 28e56b8 | 2010-09-20 14:38:38 -0700 | [diff] [blame] | 409 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 410 | // Discover a Reference object, using appropriate discovery criteria |
| 411 | bool discover_reference(oop obj, ReferenceType rt); |
| 412 | |
| 413 | // Process references found during GC (called by the garbage collector) |
Staffan Larsen | 718f325 | 2013-06-10 11:30:51 +0200 | [diff] [blame] | 414 | ReferenceProcessorStats |
| 415 | process_discovered_references(BoolObjectClosure* is_alive, |
| 416 | OopClosure* keep_alive, |
| 417 | VoidClosure* complete_gc, |
| 418 | AbstractRefProcTaskExecutor* task_executor, |
Bengt Rutisson | 003892f | 2015-09-30 09:07:21 +0200 | [diff] [blame] | 419 | GCTimer *gc_timer); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 420 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 421 | // Enqueue references at end of GC (called by the garbage collector) |
| 422 | bool enqueue_discovered_references(AbstractRefProcTaskExecutor* task_executor = NULL); |
| 423 | |
Y. Srinivas Ramakrishna | 18f3386 | 2008-06-05 15:57:56 -0700 | [diff] [blame] | 424 | // If a discovery is in process that is being superceded, abandon it: all |
| 425 | // the discovered lists will be empty, and all the objects on them will |
| 426 | // have NULL discovered fields. Must be called only at a safepoint. |
| 427 | void abandon_partial_discovery(); |
| 428 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 429 | // debugging |
| 430 | void verify_no_references_recorded() PRODUCT_RETURN; |
Y. Srinivas Ramakrishna | 8baafdf | 2010-12-09 09:22:57 -0800 | [diff] [blame] | 431 | void verify_referent(oop obj) PRODUCT_RETURN; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 432 | }; |
| 433 | |
| 434 | // A utility class to disable reference discovery in |
| 435 | // the scope which contains it, for given ReferenceProcessor. |
| 436 | class NoRefDiscovery: StackObj { |
| 437 | private: |
| 438 | ReferenceProcessor* _rp; |
| 439 | bool _was_discovering_refs; |
| 440 | public: |
| 441 | NoRefDiscovery(ReferenceProcessor* rp) : _rp(rp) { |
Pavel Tisnovsky | af25487 | 2010-09-09 05:24:11 -0700 | [diff] [blame] | 442 | _was_discovering_refs = _rp->discovery_enabled(); |
| 443 | if (_was_discovering_refs) { |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 444 | _rp->disable_discovery(); |
| 445 | } |
| 446 | } |
| 447 | |
| 448 | ~NoRefDiscovery() { |
| 449 | if (_was_discovering_refs) { |
Kim Barrett | 093d269 | 2014-12-17 22:32:44 -0500 | [diff] [blame] | 450 | _rp->enable_discovery(false /*check_no_refs*/); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 451 | } |
| 452 | } |
| 453 | }; |
| 454 | |
| 455 | |
| 456 | // A utility class to temporarily mutate the span of the |
| 457 | // given ReferenceProcessor in the scope that contains it. |
| 458 | class ReferenceProcessorSpanMutator: StackObj { |
| 459 | private: |
| 460 | ReferenceProcessor* _rp; |
| 461 | MemRegion _saved_span; |
| 462 | |
| 463 | public: |
| 464 | ReferenceProcessorSpanMutator(ReferenceProcessor* rp, |
| 465 | MemRegion span): |
| 466 | _rp(rp) { |
| 467 | _saved_span = _rp->span(); |
| 468 | _rp->set_span(span); |
| 469 | } |
| 470 | |
| 471 | ~ReferenceProcessorSpanMutator() { |
| 472 | _rp->set_span(_saved_span); |
| 473 | } |
| 474 | }; |
| 475 | |
| 476 | // A utility class to temporarily change the MT'ness of |
| 477 | // reference discovery for the given ReferenceProcessor |
| 478 | // in the scope that contains it. |
Y. Srinivas Ramakrishna | b4b287e | 2011-03-17 10:32:46 -0700 | [diff] [blame] | 479 | class ReferenceProcessorMTDiscoveryMutator: StackObj { |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 480 | private: |
| 481 | ReferenceProcessor* _rp; |
| 482 | bool _saved_mt; |
| 483 | |
| 484 | public: |
Y. Srinivas Ramakrishna | b4b287e | 2011-03-17 10:32:46 -0700 | [diff] [blame] | 485 | ReferenceProcessorMTDiscoveryMutator(ReferenceProcessor* rp, |
| 486 | bool mt): |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 487 | _rp(rp) { |
| 488 | _saved_mt = _rp->discovery_is_mt(); |
| 489 | _rp->set_mt_discovery(mt); |
| 490 | } |
| 491 | |
Y. Srinivas Ramakrishna | b4b287e | 2011-03-17 10:32:46 -0700 | [diff] [blame] | 492 | ~ReferenceProcessorMTDiscoveryMutator() { |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 493 | _rp->set_mt_discovery(_saved_mt); |
| 494 | } |
| 495 | }; |
| 496 | |
| 497 | |
| 498 | // A utility class to temporarily change the disposition |
| 499 | // of the "is_alive_non_header" closure field of the |
| 500 | // given ReferenceProcessor in the scope that contains it. |
| 501 | class ReferenceProcessorIsAliveMutator: StackObj { |
| 502 | private: |
| 503 | ReferenceProcessor* _rp; |
| 504 | BoolObjectClosure* _saved_cl; |
| 505 | |
| 506 | public: |
| 507 | ReferenceProcessorIsAliveMutator(ReferenceProcessor* rp, |
| 508 | BoolObjectClosure* cl): |
| 509 | _rp(rp) { |
| 510 | _saved_cl = _rp->is_alive_non_header(); |
| 511 | _rp->set_is_alive_non_header(cl); |
| 512 | } |
| 513 | |
| 514 | ~ReferenceProcessorIsAliveMutator() { |
| 515 | _rp->set_is_alive_non_header(_saved_cl); |
| 516 | } |
| 517 | }; |
| 518 | |
| 519 | // A utility class to temporarily change the disposition |
| 520 | // of the "discovery_is_atomic" field of the |
| 521 | // given ReferenceProcessor in the scope that contains it. |
| 522 | class ReferenceProcessorAtomicMutator: StackObj { |
| 523 | private: |
| 524 | ReferenceProcessor* _rp; |
| 525 | bool _saved_atomic_discovery; |
| 526 | |
| 527 | public: |
| 528 | ReferenceProcessorAtomicMutator(ReferenceProcessor* rp, |
| 529 | bool atomic): |
| 530 | _rp(rp) { |
| 531 | _saved_atomic_discovery = _rp->discovery_is_atomic(); |
| 532 | _rp->set_atomic_discovery(atomic); |
| 533 | } |
| 534 | |
| 535 | ~ReferenceProcessorAtomicMutator() { |
| 536 | _rp->set_atomic_discovery(_saved_atomic_discovery); |
| 537 | } |
| 538 | }; |
| 539 | |
| 540 | |
| 541 | // A utility class to temporarily change the MT processing |
| 542 | // disposition of the given ReferenceProcessor instance |
| 543 | // in the scope that contains it. |
| 544 | class ReferenceProcessorMTProcMutator: StackObj { |
| 545 | private: |
| 546 | ReferenceProcessor* _rp; |
| 547 | bool _saved_mt; |
| 548 | |
| 549 | public: |
| 550 | ReferenceProcessorMTProcMutator(ReferenceProcessor* rp, |
| 551 | bool mt): |
| 552 | _rp(rp) { |
| 553 | _saved_mt = _rp->processing_is_mt(); |
| 554 | _rp->set_mt_processing(mt); |
| 555 | } |
| 556 | |
| 557 | ~ReferenceProcessorMTProcMutator() { |
| 558 | _rp->set_mt_processing(_saved_mt); |
| 559 | } |
| 560 | }; |
| 561 | |
| 562 | |
| 563 | // This class is an interface used to implement task execution for the |
| 564 | // reference processing. |
| 565 | class AbstractRefProcTaskExecutor { |
| 566 | public: |
| 567 | |
| 568 | // Abstract tasks to execute. |
| 569 | class ProcessTask; |
| 570 | class EnqueueTask; |
| 571 | |
| 572 | // Executes a task using worker threads. |
| 573 | virtual void execute(ProcessTask& task) = 0; |
| 574 | virtual void execute(EnqueueTask& task) = 0; |
| 575 | |
| 576 | // Switch to single threaded mode. |
| 577 | virtual void set_single_threaded_mode() { }; |
| 578 | }; |
| 579 | |
| 580 | // Abstract reference processing task to execute. |
| 581 | class AbstractRefProcTaskExecutor::ProcessTask { |
| 582 | protected: |
| 583 | ProcessTask(ReferenceProcessor& ref_processor, |
| 584 | DiscoveredList refs_lists[], |
| 585 | bool marks_oops_alive) |
| 586 | : _ref_processor(ref_processor), |
| 587 | _refs_lists(refs_lists), |
| 588 | _marks_oops_alive(marks_oops_alive) |
| 589 | { } |
| 590 | |
| 591 | public: |
| 592 | virtual void work(unsigned int work_id, BoolObjectClosure& is_alive, |
| 593 | OopClosure& keep_alive, |
| 594 | VoidClosure& complete_gc) = 0; |
| 595 | |
| 596 | // Returns true if a task marks some oops as alive. |
| 597 | bool marks_oops_alive() const |
| 598 | { return _marks_oops_alive; } |
| 599 | |
| 600 | protected: |
| 601 | ReferenceProcessor& _ref_processor; |
| 602 | DiscoveredList* _refs_lists; |
| 603 | const bool _marks_oops_alive; |
| 604 | }; |
| 605 | |
| 606 | // Abstract reference processing task to execute. |
| 607 | class AbstractRefProcTaskExecutor::EnqueueTask { |
| 608 | protected: |
| 609 | EnqueueTask(ReferenceProcessor& ref_processor, |
| 610 | DiscoveredList refs_lists[], |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 611 | HeapWord* pending_list_addr, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 612 | int n_queues) |
| 613 | : _ref_processor(ref_processor), |
| 614 | _refs_lists(refs_lists), |
| 615 | _pending_list_addr(pending_list_addr), |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 616 | _n_queues(n_queues) |
| 617 | { } |
| 618 | |
| 619 | public: |
| 620 | virtual void work(unsigned int work_id) = 0; |
| 621 | |
| 622 | protected: |
| 623 | ReferenceProcessor& _ref_processor; |
| 624 | DiscoveredList* _refs_lists; |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 625 | HeapWord* _pending_list_addr; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 626 | int _n_queues; |
| 627 | }; |
Stefan Karlsson | 8006fe8 | 2010-11-23 13:22:55 -0800 | [diff] [blame] | 628 | |
Per Lidén | 4dc240f | 2015-05-13 15:16:06 +0200 | [diff] [blame] | 629 | #endif // SHARE_VM_GC_SHARED_REFERENCEPROCESSOR_HPP |