J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 1 | /* |
Xiomara Jayasena | c96a95c | 2008-07-02 12:55:16 -0700 | [diff] [blame] | 2 | * Copyright 2001-2008 Sun Microsystems, Inc. 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 | * |
| 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | // ReferenceProcessor class encapsulates the per-"collector" processing |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 26 | // 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] | 27 | // a generational abstraction, in particular when there are multiple |
| 28 | // generations that are being independently collected -- possibly |
| 29 | // concurrently and/or incrementally. Note, however, that the |
| 30 | // ReferenceProcessor class abstracts away from a generational setting |
| 31 | // by using only a heap interval (called "span" below), thus allowing |
| 32 | // its use in a straightforward manner in a general, non-generational |
| 33 | // setting. |
| 34 | // |
| 35 | // The basic idea is that each ReferenceProcessor object concerns |
| 36 | // itself with ("weak") reference processing in a specific "span" |
| 37 | // of the heap of interest to a specific collector. Currently, |
| 38 | // the span is a convex interval of the heap, but, efficiency |
| 39 | // apart, there seems to be no reason it couldn't be extended |
| 40 | // (with appropriate modifications) to any "non-convex interval". |
| 41 | |
| 42 | // forward references |
| 43 | class ReferencePolicy; |
| 44 | class AbstractRefProcTaskExecutor; |
| 45 | class DiscoveredList; |
| 46 | |
| 47 | class ReferenceProcessor : public CHeapObj { |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 48 | protected: |
| 49 | // End of list marker |
| 50 | static oop _sentinelRef; |
| 51 | MemRegion _span; // (right-open) interval of heap |
| 52 | // subject to wkref discovery |
| 53 | bool _discovering_refs; // true when discovery enabled |
| 54 | bool _discovery_is_atomic; // if discovery is atomic wrt |
| 55 | // other collectors in configuration |
| 56 | bool _discovery_is_mt; // true if reference discovery is MT. |
Y. Srinivas Ramakrishna | 18f3386 | 2008-06-05 15:57:56 -0700 | [diff] [blame] | 57 | // If true, setting "next" field of a discovered refs list requires |
| 58 | // write barrier(s). (Must be true if used in a collector in which |
| 59 | // elements of a discovered list may be moved during discovery: for |
| 60 | // example, a collector like Garbage-First that moves objects during a |
| 61 | // long-term concurrent marking phase that does weak reference |
| 62 | // discovery.) |
| 63 | bool _discovered_list_needs_barrier; |
| 64 | BarrierSet* _bs; // Cached copy of BarrierSet. |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 65 | bool _enqueuing_is_done; // true if all weak references enqueued |
| 66 | bool _processing_is_mt; // true during phases when |
| 67 | // reference processing is MT. |
| 68 | int _next_id; // round-robin counter in |
| 69 | // support of work distribution |
| 70 | |
| 71 | // For collectors that do not keep GC marking information |
| 72 | // in the object header, this field holds a closure that |
| 73 | // helps the reference processor determine the reachability |
| 74 | // of an oop (the field is currently initialized to NULL for |
| 75 | // all collectors but the CMS collector). |
| 76 | BoolObjectClosure* _is_alive_non_header; |
| 77 | |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 78 | // Soft ref clearing policies |
| 79 | // . the default policy |
| 80 | static ReferencePolicy* _default_soft_ref_policy; |
| 81 | // . the "clear all" policy |
| 82 | static ReferencePolicy* _always_clear_soft_ref_policy; |
| 83 | // . the current policy below is either one of the above |
| 84 | ReferencePolicy* _current_soft_ref_policy; |
| 85 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 86 | // The discovered ref lists themselves |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 87 | |
| 88 | // The MT'ness degree of the queues below |
| 89 | int _num_q; |
| 90 | // Arrays of lists of oops, one per thread |
| 91 | DiscoveredList* _discoveredSoftRefs; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 92 | DiscoveredList* _discoveredWeakRefs; |
| 93 | DiscoveredList* _discoveredFinalRefs; |
| 94 | DiscoveredList* _discoveredPhantomRefs; |
| 95 | |
| 96 | public: |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 97 | int num_q() { return _num_q; } |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 98 | DiscoveredList* discovered_soft_refs() { return _discoveredSoftRefs; } |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 99 | static oop sentinel_ref() { return _sentinelRef; } |
| 100 | static oop* adr_sentinel_ref() { return &_sentinelRef; } |
Y. Srinivas Ramakrishna | 16aa57c | 2008-12-01 23:25:24 -0800 | [diff] [blame] | 101 | ReferencePolicy* setup_policy(bool always_clear) { |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 102 | _current_soft_ref_policy = always_clear ? |
| 103 | _always_clear_soft_ref_policy : _default_soft_ref_policy; |
Y. Srinivas Ramakrishna | 16aa57c | 2008-12-01 23:25:24 -0800 | [diff] [blame] | 104 | _current_soft_ref_policy->setup(); // snapshot the policy threshold |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 105 | return _current_soft_ref_policy; |
| 106 | } |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 107 | |
| 108 | public: |
| 109 | // Process references with a certain reachability level. |
| 110 | void process_discovered_reflist(DiscoveredList refs_lists[], |
| 111 | ReferencePolicy* policy, |
| 112 | bool clear_referent, |
| 113 | BoolObjectClosure* is_alive, |
| 114 | OopClosure* keep_alive, |
| 115 | VoidClosure* complete_gc, |
| 116 | AbstractRefProcTaskExecutor* task_executor); |
| 117 | |
| 118 | void process_phaseJNI(BoolObjectClosure* is_alive, |
| 119 | OopClosure* keep_alive, |
| 120 | VoidClosure* complete_gc); |
| 121 | |
| 122 | // Work methods used by the method process_discovered_reflist |
| 123 | // Phase1: keep alive all those referents that are otherwise |
| 124 | // dead but which must be kept alive by policy (and their closure). |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 125 | void process_phase1(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 126 | ReferencePolicy* policy, |
| 127 | BoolObjectClosure* is_alive, |
| 128 | OopClosure* keep_alive, |
| 129 | VoidClosure* complete_gc); |
| 130 | // Phase2: remove all those references whose referents are |
| 131 | // reachable. |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 132 | inline void process_phase2(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 133 | BoolObjectClosure* is_alive, |
| 134 | OopClosure* keep_alive, |
| 135 | VoidClosure* complete_gc) { |
| 136 | if (discovery_is_atomic()) { |
| 137 | // complete_gc is ignored in this case for this phase |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 138 | pp2_work(refs_list, is_alive, keep_alive); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 139 | } else { |
| 140 | assert(complete_gc != NULL, "Error"); |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 141 | pp2_work_concurrent_discovery(refs_list, is_alive, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 142 | keep_alive, complete_gc); |
| 143 | } |
| 144 | } |
| 145 | // Work methods in support of process_phase2 |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 146 | void pp2_work(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 147 | BoolObjectClosure* is_alive, |
| 148 | OopClosure* keep_alive); |
| 149 | void pp2_work_concurrent_discovery( |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 150 | DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 151 | BoolObjectClosure* is_alive, |
| 152 | OopClosure* keep_alive, |
| 153 | VoidClosure* complete_gc); |
| 154 | // Phase3: process the referents by either clearing them |
| 155 | // or keeping them alive (and their closure) |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 156 | void process_phase3(DiscoveredList& refs_list, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 157 | bool clear_referent, |
| 158 | BoolObjectClosure* is_alive, |
| 159 | OopClosure* keep_alive, |
| 160 | VoidClosure* complete_gc); |
| 161 | |
| 162 | // Enqueue references with a certain reachability level |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 163 | void enqueue_discovered_reflist(DiscoveredList& refs_list, HeapWord* pending_list_addr); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 164 | |
| 165 | // "Preclean" all the discovered reference lists |
| 166 | // by removing references with strongly reachable referents. |
| 167 | // The first argument is a predicate on an oop that indicates |
| 168 | // its (strong) reachability and the second is a closure that |
| 169 | // may be used to incrementalize or abort the precleaning process. |
| 170 | // The caller is responsible for taking care of potential |
| 171 | // interference with concurrent operations on these lists |
| 172 | // (or predicates involved) by other threads. Currently |
Jon Masamitsu | b2ed547 | 2010-01-21 11:33:32 -0800 | [diff] [blame] | 173 | // only used by the CMS collector. should_unload_classes is |
| 174 | // used to aid assertion checking when classes are collected. |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 175 | void preclean_discovered_references(BoolObjectClosure* is_alive, |
| 176 | OopClosure* keep_alive, |
| 177 | VoidClosure* complete_gc, |
Jon Masamitsu | b2ed547 | 2010-01-21 11:33:32 -0800 | [diff] [blame] | 178 | YieldClosure* yield, |
| 179 | bool should_unload_classes); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 180 | |
| 181 | // Delete entries in the discovered lists that have |
| 182 | // either a null referent or are not active. Such |
| 183 | // Reference objects can result from the clearing |
| 184 | // or enqueueing of Reference objects concurrent |
| 185 | // with their discovery by a (concurrent) collector. |
| 186 | // For a definition of "active" see java.lang.ref.Reference; |
| 187 | // Refs are born active, become inactive when enqueued, |
| 188 | // and never become active again. The state of being |
| 189 | // active is encoded as follows: A Ref is active |
| 190 | // if and only if its "next" field is NULL. |
| 191 | void clean_up_discovered_references(); |
| 192 | void clean_up_discovered_reflist(DiscoveredList& refs_list); |
| 193 | |
| 194 | // Returns the name of the discovered reference list |
| 195 | // occupying the i / _num_q slot. |
| 196 | const char* list_name(int i); |
| 197 | |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 198 | void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor); |
| 199 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 200 | protected: |
| 201 | // "Preclean" the given discovered reference list |
| 202 | // by removing references with strongly reachable referents. |
| 203 | // Currently used in support of CMS only. |
| 204 | void preclean_discovered_reflist(DiscoveredList& refs_list, |
| 205 | BoolObjectClosure* is_alive, |
| 206 | OopClosure* keep_alive, |
| 207 | VoidClosure* complete_gc, |
| 208 | YieldClosure* yield); |
| 209 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 210 | int next_id() { |
| 211 | int id = _next_id; |
| 212 | if (++_next_id == _num_q) { |
| 213 | _next_id = 0; |
| 214 | } |
| 215 | return id; |
| 216 | } |
| 217 | DiscoveredList* get_discovered_list(ReferenceType rt); |
| 218 | inline void add_to_discovered_list_mt(DiscoveredList& refs_list, oop obj, |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 219 | HeapWord* discovered_addr); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 220 | void verify_ok_to_handle_reflists() PRODUCT_RETURN; |
| 221 | |
| 222 | void abandon_partial_discovered_list(DiscoveredList& refs_list); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 223 | |
| 224 | // Calculate the number of jni handles. |
| 225 | unsigned int count_jni_refs(); |
| 226 | |
| 227 | // Balances reference queues. |
| 228 | void balance_queues(DiscoveredList ref_lists[]); |
| 229 | |
| 230 | // Update (advance) the soft ref master clock field. |
| 231 | void update_soft_ref_master_clock(); |
| 232 | |
| 233 | public: |
| 234 | // constructor |
| 235 | ReferenceProcessor(): |
| 236 | _span((HeapWord*)NULL, (HeapWord*)NULL), |
| 237 | _discoveredSoftRefs(NULL), _discoveredWeakRefs(NULL), |
| 238 | _discoveredFinalRefs(NULL), _discoveredPhantomRefs(NULL), |
| 239 | _discovering_refs(false), |
| 240 | _discovery_is_atomic(true), |
| 241 | _enqueuing_is_done(false), |
| 242 | _discovery_is_mt(false), |
Y. Srinivas Ramakrishna | 18f3386 | 2008-06-05 15:57:56 -0700 | [diff] [blame] | 243 | _discovered_list_needs_barrier(false), |
| 244 | _bs(NULL), |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 245 | _is_alive_non_header(NULL), |
| 246 | _num_q(0), |
| 247 | _processing_is_mt(false), |
| 248 | _next_id(0) |
| 249 | {} |
| 250 | |
| 251 | ReferenceProcessor(MemRegion span, bool atomic_discovery, |
Y. Srinivas Ramakrishna | 18f3386 | 2008-06-05 15:57:56 -0700 | [diff] [blame] | 252 | bool mt_discovery, |
| 253 | int mt_degree = 1, |
| 254 | bool mt_processing = false, |
| 255 | bool discovered_list_needs_barrier = false); |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 256 | |
| 257 | // Allocates and initializes a reference processor. |
| 258 | static ReferenceProcessor* create_ref_processor( |
| 259 | MemRegion span, |
| 260 | bool atomic_discovery, |
| 261 | bool mt_discovery, |
| 262 | BoolObjectClosure* is_alive_non_header = NULL, |
| 263 | int parallel_gc_threads = 1, |
Y. Srinivas Ramakrishna | 18f3386 | 2008-06-05 15:57:56 -0700 | [diff] [blame] | 264 | bool mt_processing = false, |
| 265 | bool discovered_list_needs_barrier = false); |
John Cuthbertson | b34027a | 2010-01-29 14:51:38 -0800 | [diff] [blame^] | 266 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 267 | // RefDiscoveryPolicy values |
John Cuthbertson | b34027a | 2010-01-29 14:51:38 -0800 | [diff] [blame^] | 268 | enum DiscoveryPolicy { |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 269 | ReferenceBasedDiscovery = 0, |
John Cuthbertson | b34027a | 2010-01-29 14:51:38 -0800 | [diff] [blame^] | 270 | ReferentBasedDiscovery = 1, |
| 271 | DiscoveryPolicyMin = ReferenceBasedDiscovery, |
| 272 | DiscoveryPolicyMax = ReferentBasedDiscovery |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 273 | }; |
| 274 | |
| 275 | static void init_statics(); |
| 276 | |
| 277 | public: |
| 278 | // get and set "is_alive_non_header" field |
| 279 | BoolObjectClosure* is_alive_non_header() { |
| 280 | return _is_alive_non_header; |
| 281 | } |
| 282 | void set_is_alive_non_header(BoolObjectClosure* is_alive_non_header) { |
| 283 | _is_alive_non_header = is_alive_non_header; |
| 284 | } |
| 285 | |
| 286 | // get and set span |
| 287 | MemRegion span() { return _span; } |
| 288 | void set_span(MemRegion span) { _span = span; } |
| 289 | |
| 290 | // start and stop weak ref discovery |
| 291 | void enable_discovery() { _discovering_refs = true; } |
| 292 | void disable_discovery() { _discovering_refs = false; } |
| 293 | bool discovery_enabled() { return _discovering_refs; } |
| 294 | |
| 295 | // whether discovery is atomic wrt other collectors |
| 296 | bool discovery_is_atomic() const { return _discovery_is_atomic; } |
| 297 | void set_atomic_discovery(bool atomic) { _discovery_is_atomic = atomic; } |
| 298 | |
| 299 | // whether discovery is done by multiple threads same-old-timeously |
| 300 | bool discovery_is_mt() const { return _discovery_is_mt; } |
| 301 | void set_mt_discovery(bool mt) { _discovery_is_mt = mt; } |
| 302 | |
| 303 | // Whether we are in a phase when _processing_ is MT. |
| 304 | bool processing_is_mt() const { return _processing_is_mt; } |
| 305 | void set_mt_processing(bool mt) { _processing_is_mt = mt; } |
| 306 | |
| 307 | // whether all enqueuing of weak references is complete |
| 308 | bool enqueuing_is_done() { return _enqueuing_is_done; } |
| 309 | void set_enqueuing_is_done(bool v) { _enqueuing_is_done = v; } |
| 310 | |
| 311 | // iterate over oops |
| 312 | void weak_oops_do(OopClosure* f); // weak roots |
| 313 | static void oops_do(OopClosure* f); // strong root(s) |
| 314 | |
| 315 | // Discover a Reference object, using appropriate discovery criteria |
| 316 | bool discover_reference(oop obj, ReferenceType rt); |
| 317 | |
| 318 | // Process references found during GC (called by the garbage collector) |
Y. Srinivas Ramakrishna | 7d7cf3f | 2008-11-20 16:56:09 -0800 | [diff] [blame] | 319 | void process_discovered_references(BoolObjectClosure* is_alive, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 320 | OopClosure* keep_alive, |
| 321 | VoidClosure* complete_gc, |
| 322 | AbstractRefProcTaskExecutor* task_executor); |
| 323 | |
| 324 | public: |
| 325 | // Enqueue references at end of GC (called by the garbage collector) |
| 326 | bool enqueue_discovered_references(AbstractRefProcTaskExecutor* task_executor = NULL); |
| 327 | |
Y. Srinivas Ramakrishna | 18f3386 | 2008-06-05 15:57:56 -0700 | [diff] [blame] | 328 | // If a discovery is in process that is being superceded, abandon it: all |
| 329 | // the discovered lists will be empty, and all the objects on them will |
| 330 | // have NULL discovered fields. Must be called only at a safepoint. |
| 331 | void abandon_partial_discovery(); |
| 332 | |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 333 | // debugging |
| 334 | void verify_no_references_recorded() PRODUCT_RETURN; |
| 335 | static void verify(); |
| 336 | |
| 337 | // clear the discovered lists (unlinking each entry). |
| 338 | void clear_discovered_references() PRODUCT_RETURN; |
| 339 | }; |
| 340 | |
| 341 | // A utility class to disable reference discovery in |
| 342 | // the scope which contains it, for given ReferenceProcessor. |
| 343 | class NoRefDiscovery: StackObj { |
| 344 | private: |
| 345 | ReferenceProcessor* _rp; |
| 346 | bool _was_discovering_refs; |
| 347 | public: |
| 348 | NoRefDiscovery(ReferenceProcessor* rp) : _rp(rp) { |
| 349 | if (_was_discovering_refs = _rp->discovery_enabled()) { |
| 350 | _rp->disable_discovery(); |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | ~NoRefDiscovery() { |
| 355 | if (_was_discovering_refs) { |
| 356 | _rp->enable_discovery(); |
| 357 | } |
| 358 | } |
| 359 | }; |
| 360 | |
| 361 | |
| 362 | // A utility class to temporarily mutate the span of the |
| 363 | // given ReferenceProcessor in the scope that contains it. |
| 364 | class ReferenceProcessorSpanMutator: StackObj { |
| 365 | private: |
| 366 | ReferenceProcessor* _rp; |
| 367 | MemRegion _saved_span; |
| 368 | |
| 369 | public: |
| 370 | ReferenceProcessorSpanMutator(ReferenceProcessor* rp, |
| 371 | MemRegion span): |
| 372 | _rp(rp) { |
| 373 | _saved_span = _rp->span(); |
| 374 | _rp->set_span(span); |
| 375 | } |
| 376 | |
| 377 | ~ReferenceProcessorSpanMutator() { |
| 378 | _rp->set_span(_saved_span); |
| 379 | } |
| 380 | }; |
| 381 | |
| 382 | // A utility class to temporarily change the MT'ness of |
| 383 | // reference discovery for the given ReferenceProcessor |
| 384 | // in the scope that contains it. |
| 385 | class ReferenceProcessorMTMutator: StackObj { |
| 386 | private: |
| 387 | ReferenceProcessor* _rp; |
| 388 | bool _saved_mt; |
| 389 | |
| 390 | public: |
| 391 | ReferenceProcessorMTMutator(ReferenceProcessor* rp, |
| 392 | bool mt): |
| 393 | _rp(rp) { |
| 394 | _saved_mt = _rp->discovery_is_mt(); |
| 395 | _rp->set_mt_discovery(mt); |
| 396 | } |
| 397 | |
| 398 | ~ReferenceProcessorMTMutator() { |
| 399 | _rp->set_mt_discovery(_saved_mt); |
| 400 | } |
| 401 | }; |
| 402 | |
| 403 | |
| 404 | // A utility class to temporarily change the disposition |
| 405 | // of the "is_alive_non_header" closure field of the |
| 406 | // given ReferenceProcessor in the scope that contains it. |
| 407 | class ReferenceProcessorIsAliveMutator: StackObj { |
| 408 | private: |
| 409 | ReferenceProcessor* _rp; |
| 410 | BoolObjectClosure* _saved_cl; |
| 411 | |
| 412 | public: |
| 413 | ReferenceProcessorIsAliveMutator(ReferenceProcessor* rp, |
| 414 | BoolObjectClosure* cl): |
| 415 | _rp(rp) { |
| 416 | _saved_cl = _rp->is_alive_non_header(); |
| 417 | _rp->set_is_alive_non_header(cl); |
| 418 | } |
| 419 | |
| 420 | ~ReferenceProcessorIsAliveMutator() { |
| 421 | _rp->set_is_alive_non_header(_saved_cl); |
| 422 | } |
| 423 | }; |
| 424 | |
| 425 | // A utility class to temporarily change the disposition |
| 426 | // of the "discovery_is_atomic" field of the |
| 427 | // given ReferenceProcessor in the scope that contains it. |
| 428 | class ReferenceProcessorAtomicMutator: StackObj { |
| 429 | private: |
| 430 | ReferenceProcessor* _rp; |
| 431 | bool _saved_atomic_discovery; |
| 432 | |
| 433 | public: |
| 434 | ReferenceProcessorAtomicMutator(ReferenceProcessor* rp, |
| 435 | bool atomic): |
| 436 | _rp(rp) { |
| 437 | _saved_atomic_discovery = _rp->discovery_is_atomic(); |
| 438 | _rp->set_atomic_discovery(atomic); |
| 439 | } |
| 440 | |
| 441 | ~ReferenceProcessorAtomicMutator() { |
| 442 | _rp->set_atomic_discovery(_saved_atomic_discovery); |
| 443 | } |
| 444 | }; |
| 445 | |
| 446 | |
| 447 | // A utility class to temporarily change the MT processing |
| 448 | // disposition of the given ReferenceProcessor instance |
| 449 | // in the scope that contains it. |
| 450 | class ReferenceProcessorMTProcMutator: StackObj { |
| 451 | private: |
| 452 | ReferenceProcessor* _rp; |
| 453 | bool _saved_mt; |
| 454 | |
| 455 | public: |
| 456 | ReferenceProcessorMTProcMutator(ReferenceProcessor* rp, |
| 457 | bool mt): |
| 458 | _rp(rp) { |
| 459 | _saved_mt = _rp->processing_is_mt(); |
| 460 | _rp->set_mt_processing(mt); |
| 461 | } |
| 462 | |
| 463 | ~ReferenceProcessorMTProcMutator() { |
| 464 | _rp->set_mt_processing(_saved_mt); |
| 465 | } |
| 466 | }; |
| 467 | |
| 468 | |
| 469 | // This class is an interface used to implement task execution for the |
| 470 | // reference processing. |
| 471 | class AbstractRefProcTaskExecutor { |
| 472 | public: |
| 473 | |
| 474 | // Abstract tasks to execute. |
| 475 | class ProcessTask; |
| 476 | class EnqueueTask; |
| 477 | |
| 478 | // Executes a task using worker threads. |
| 479 | virtual void execute(ProcessTask& task) = 0; |
| 480 | virtual void execute(EnqueueTask& task) = 0; |
| 481 | |
| 482 | // Switch to single threaded mode. |
| 483 | virtual void set_single_threaded_mode() { }; |
| 484 | }; |
| 485 | |
| 486 | // Abstract reference processing task to execute. |
| 487 | class AbstractRefProcTaskExecutor::ProcessTask { |
| 488 | protected: |
| 489 | ProcessTask(ReferenceProcessor& ref_processor, |
| 490 | DiscoveredList refs_lists[], |
| 491 | bool marks_oops_alive) |
| 492 | : _ref_processor(ref_processor), |
| 493 | _refs_lists(refs_lists), |
| 494 | _marks_oops_alive(marks_oops_alive) |
| 495 | { } |
| 496 | |
| 497 | public: |
| 498 | virtual void work(unsigned int work_id, BoolObjectClosure& is_alive, |
| 499 | OopClosure& keep_alive, |
| 500 | VoidClosure& complete_gc) = 0; |
| 501 | |
| 502 | // Returns true if a task marks some oops as alive. |
| 503 | bool marks_oops_alive() const |
| 504 | { return _marks_oops_alive; } |
| 505 | |
| 506 | protected: |
| 507 | ReferenceProcessor& _ref_processor; |
| 508 | DiscoveredList* _refs_lists; |
| 509 | const bool _marks_oops_alive; |
| 510 | }; |
| 511 | |
| 512 | // Abstract reference processing task to execute. |
| 513 | class AbstractRefProcTaskExecutor::EnqueueTask { |
| 514 | protected: |
| 515 | EnqueueTask(ReferenceProcessor& ref_processor, |
| 516 | DiscoveredList refs_lists[], |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 517 | HeapWord* pending_list_addr, |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 518 | oop sentinel_ref, |
| 519 | int n_queues) |
| 520 | : _ref_processor(ref_processor), |
| 521 | _refs_lists(refs_lists), |
| 522 | _pending_list_addr(pending_list_addr), |
| 523 | _sentinel_ref(sentinel_ref), |
| 524 | _n_queues(n_queues) |
| 525 | { } |
| 526 | |
| 527 | public: |
| 528 | virtual void work(unsigned int work_id) = 0; |
| 529 | |
| 530 | protected: |
| 531 | ReferenceProcessor& _ref_processor; |
| 532 | DiscoveredList* _refs_lists; |
Coleen Phillimore | 4a831d4 | 2008-04-13 17:43:42 -0400 | [diff] [blame] | 533 | HeapWord* _pending_list_addr; |
J. Duke | 8153779 | 2007-12-01 00:00:00 +0000 | [diff] [blame] | 534 | oop _sentinel_ref; |
| 535 | int _n_queues; |
| 536 | }; |