Thu, 12 Oct 2017 21:27:07 +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_REFERENCEPROCESSOR_HPP |
aoqi@0 | 26 | #define SHARE_VM_MEMORY_REFERENCEPROCESSOR_HPP |
aoqi@0 | 27 | |
brutisso@6904 | 28 | #include "gc_implementation/shared/gcTrace.hpp" |
aoqi@0 | 29 | #include "memory/referencePolicy.hpp" |
aoqi@0 | 30 | #include "memory/referenceProcessorStats.hpp" |
aoqi@0 | 31 | #include "memory/referenceType.hpp" |
aoqi@0 | 32 | #include "oops/instanceRefKlass.hpp" |
aoqi@0 | 33 | |
aoqi@0 | 34 | class GCTimer; |
aoqi@0 | 35 | |
aoqi@0 | 36 | // ReferenceProcessor class encapsulates the per-"collector" processing |
aoqi@0 | 37 | // of java.lang.Reference objects for GC. The interface is useful for supporting |
aoqi@0 | 38 | // a generational abstraction, in particular when there are multiple |
aoqi@0 | 39 | // generations that are being independently collected -- possibly |
aoqi@0 | 40 | // concurrently and/or incrementally. Note, however, that the |
aoqi@0 | 41 | // ReferenceProcessor class abstracts away from a generational setting |
aoqi@0 | 42 | // by using only a heap interval (called "span" below), thus allowing |
aoqi@0 | 43 | // its use in a straightforward manner in a general, non-generational |
aoqi@0 | 44 | // setting. |
aoqi@0 | 45 | // |
aoqi@0 | 46 | // The basic idea is that each ReferenceProcessor object concerns |
aoqi@0 | 47 | // itself with ("weak") reference processing in a specific "span" |
aoqi@0 | 48 | // of the heap of interest to a specific collector. Currently, |
aoqi@0 | 49 | // the span is a convex interval of the heap, but, efficiency |
aoqi@0 | 50 | // apart, there seems to be no reason it couldn't be extended |
aoqi@0 | 51 | // (with appropriate modifications) to any "non-convex interval". |
aoqi@0 | 52 | |
aoqi@0 | 53 | // forward references |
aoqi@0 | 54 | class ReferencePolicy; |
aoqi@0 | 55 | class AbstractRefProcTaskExecutor; |
aoqi@0 | 56 | |
aoqi@0 | 57 | // List of discovered references. |
aoqi@0 | 58 | class DiscoveredList { |
aoqi@0 | 59 | public: |
aoqi@0 | 60 | DiscoveredList() : _len(0), _compressed_head(0), _oop_head(NULL) { } |
aoqi@0 | 61 | oop head() const { |
aoqi@0 | 62 | return UseCompressedOops ? oopDesc::decode_heap_oop(_compressed_head) : |
aoqi@0 | 63 | _oop_head; |
aoqi@0 | 64 | } |
aoqi@0 | 65 | HeapWord* adr_head() { |
aoqi@0 | 66 | return UseCompressedOops ? (HeapWord*)&_compressed_head : |
aoqi@0 | 67 | (HeapWord*)&_oop_head; |
aoqi@0 | 68 | } |
aoqi@0 | 69 | void set_head(oop o) { |
aoqi@0 | 70 | if (UseCompressedOops) { |
aoqi@0 | 71 | // Must compress the head ptr. |
aoqi@0 | 72 | _compressed_head = oopDesc::encode_heap_oop(o); |
aoqi@0 | 73 | } else { |
aoqi@0 | 74 | _oop_head = o; |
aoqi@0 | 75 | } |
aoqi@0 | 76 | } |
aoqi@0 | 77 | bool is_empty() const { return head() == NULL; } |
aoqi@0 | 78 | size_t length() { return _len; } |
aoqi@0 | 79 | void set_length(size_t len) { _len = len; } |
aoqi@0 | 80 | void inc_length(size_t inc) { _len += inc; assert(_len > 0, "Error"); } |
aoqi@0 | 81 | void dec_length(size_t dec) { _len -= dec; } |
aoqi@0 | 82 | private: |
aoqi@0 | 83 | // Set value depending on UseCompressedOops. This could be a template class |
aoqi@0 | 84 | // but then we have to fix all the instantiations and declarations that use this class. |
aoqi@0 | 85 | oop _oop_head; |
aoqi@0 | 86 | narrowOop _compressed_head; |
aoqi@0 | 87 | size_t _len; |
aoqi@0 | 88 | }; |
aoqi@0 | 89 | |
aoqi@0 | 90 | // Iterator for the list of discovered references. |
aoqi@0 | 91 | class DiscoveredListIterator { |
aoqi@0 | 92 | private: |
aoqi@0 | 93 | DiscoveredList& _refs_list; |
aoqi@0 | 94 | HeapWord* _prev_next; |
aoqi@0 | 95 | oop _prev; |
aoqi@0 | 96 | oop _ref; |
aoqi@0 | 97 | HeapWord* _discovered_addr; |
aoqi@0 | 98 | oop _next; |
aoqi@0 | 99 | HeapWord* _referent_addr; |
aoqi@0 | 100 | oop _referent; |
aoqi@0 | 101 | OopClosure* _keep_alive; |
aoqi@0 | 102 | BoolObjectClosure* _is_alive; |
aoqi@0 | 103 | |
aoqi@0 | 104 | DEBUG_ONLY( |
aoqi@0 | 105 | oop _first_seen; // cyclic linked list check |
aoqi@0 | 106 | ) |
aoqi@0 | 107 | |
aoqi@0 | 108 | NOT_PRODUCT( |
aoqi@0 | 109 | size_t _processed; |
aoqi@0 | 110 | size_t _removed; |
aoqi@0 | 111 | ) |
aoqi@0 | 112 | |
aoqi@0 | 113 | public: |
aoqi@0 | 114 | inline DiscoveredListIterator(DiscoveredList& refs_list, |
aoqi@0 | 115 | OopClosure* keep_alive, |
aoqi@0 | 116 | BoolObjectClosure* is_alive): |
aoqi@0 | 117 | _refs_list(refs_list), |
aoqi@0 | 118 | _prev_next(refs_list.adr_head()), |
aoqi@0 | 119 | _prev(NULL), |
aoqi@0 | 120 | _ref(refs_list.head()), |
aoqi@0 | 121 | #ifdef ASSERT |
aoqi@0 | 122 | _first_seen(refs_list.head()), |
aoqi@0 | 123 | #endif |
aoqi@0 | 124 | #ifndef PRODUCT |
aoqi@0 | 125 | _processed(0), |
aoqi@0 | 126 | _removed(0), |
aoqi@0 | 127 | #endif |
aoqi@0 | 128 | _next(NULL), |
aoqi@0 | 129 | _keep_alive(keep_alive), |
aoqi@0 | 130 | _is_alive(is_alive) |
aoqi@0 | 131 | { } |
aoqi@0 | 132 | |
aoqi@0 | 133 | // End Of List. |
aoqi@0 | 134 | inline bool has_next() const { return _ref != NULL; } |
aoqi@0 | 135 | |
aoqi@0 | 136 | // Get oop to the Reference object. |
aoqi@0 | 137 | inline oop obj() const { return _ref; } |
aoqi@0 | 138 | |
aoqi@0 | 139 | // Get oop to the referent object. |
aoqi@0 | 140 | inline oop referent() const { return _referent; } |
aoqi@0 | 141 | |
aoqi@0 | 142 | // Returns true if referent is alive. |
aoqi@0 | 143 | inline bool is_referent_alive() const { |
aoqi@0 | 144 | return _is_alive->do_object_b(_referent); |
aoqi@0 | 145 | } |
aoqi@0 | 146 | |
aoqi@0 | 147 | // Loads data for the current reference. |
aoqi@0 | 148 | // The "allow_null_referent" argument tells us to allow for the possibility |
aoqi@0 | 149 | // of a NULL referent in the discovered Reference object. This typically |
aoqi@0 | 150 | // happens in the case of concurrent collectors that may have done the |
aoqi@0 | 151 | // discovery concurrently, or interleaved, with mutator execution. |
aoqi@0 | 152 | void load_ptrs(DEBUG_ONLY(bool allow_null_referent)); |
aoqi@0 | 153 | |
aoqi@0 | 154 | // Move to the next discovered reference. |
aoqi@0 | 155 | inline void next() { |
aoqi@0 | 156 | _prev_next = _discovered_addr; |
aoqi@0 | 157 | _prev = _ref; |
aoqi@0 | 158 | move_to_next(); |
aoqi@0 | 159 | } |
aoqi@0 | 160 | |
aoqi@0 | 161 | // Remove the current reference from the list |
aoqi@0 | 162 | void remove(); |
aoqi@0 | 163 | |
aoqi@0 | 164 | // Make the Reference object active again. |
aoqi@0 | 165 | void make_active(); |
aoqi@0 | 166 | |
aoqi@0 | 167 | // Make the referent alive. |
aoqi@0 | 168 | inline void make_referent_alive() { |
aoqi@0 | 169 | if (UseCompressedOops) { |
aoqi@0 | 170 | _keep_alive->do_oop((narrowOop*)_referent_addr); |
aoqi@0 | 171 | } else { |
aoqi@0 | 172 | _keep_alive->do_oop((oop*)_referent_addr); |
aoqi@0 | 173 | } |
aoqi@0 | 174 | } |
aoqi@0 | 175 | |
aoqi@0 | 176 | // Update the discovered field. |
aoqi@0 | 177 | inline void update_discovered() { |
aoqi@0 | 178 | // First _prev_next ref actually points into DiscoveredList (gross). |
aoqi@0 | 179 | if (UseCompressedOops) { |
aoqi@0 | 180 | if (!oopDesc::is_null(*(narrowOop*)_prev_next)) { |
aoqi@0 | 181 | _keep_alive->do_oop((narrowOop*)_prev_next); |
aoqi@0 | 182 | } |
aoqi@0 | 183 | } else { |
aoqi@0 | 184 | if (!oopDesc::is_null(*(oop*)_prev_next)) { |
aoqi@0 | 185 | _keep_alive->do_oop((oop*)_prev_next); |
aoqi@0 | 186 | } |
aoqi@0 | 187 | } |
aoqi@0 | 188 | } |
aoqi@0 | 189 | |
aoqi@0 | 190 | // NULL out referent pointer. |
aoqi@0 | 191 | void clear_referent(); |
aoqi@0 | 192 | |
aoqi@0 | 193 | // Statistics |
aoqi@0 | 194 | NOT_PRODUCT( |
aoqi@0 | 195 | inline size_t processed() const { return _processed; } |
aoqi@0 | 196 | inline size_t removed() const { return _removed; } |
aoqi@0 | 197 | ) |
aoqi@0 | 198 | |
aoqi@0 | 199 | inline void move_to_next() { |
aoqi@0 | 200 | if (_ref == _next) { |
aoqi@0 | 201 | // End of the list. |
aoqi@0 | 202 | _ref = NULL; |
aoqi@0 | 203 | } else { |
aoqi@0 | 204 | _ref = _next; |
aoqi@0 | 205 | } |
aoqi@0 | 206 | assert(_ref != _first_seen, "cyclic ref_list found"); |
aoqi@0 | 207 | NOT_PRODUCT(_processed++); |
aoqi@0 | 208 | } |
aoqi@0 | 209 | }; |
aoqi@0 | 210 | |
aoqi@0 | 211 | class ReferenceProcessor : public CHeapObj<mtGC> { |
aoqi@0 | 212 | |
aoqi@0 | 213 | private: |
aoqi@0 | 214 | size_t total_count(DiscoveredList lists[]); |
aoqi@0 | 215 | |
aoqi@0 | 216 | protected: |
aoqi@0 | 217 | // Compatibility with pre-4965777 JDK's |
aoqi@0 | 218 | static bool _pending_list_uses_discovered_field; |
aoqi@0 | 219 | |
aoqi@0 | 220 | // The SoftReference master timestamp clock |
aoqi@0 | 221 | static jlong _soft_ref_timestamp_clock; |
aoqi@0 | 222 | |
aoqi@0 | 223 | MemRegion _span; // (right-open) interval of heap |
aoqi@0 | 224 | // subject to wkref discovery |
aoqi@0 | 225 | |
aoqi@0 | 226 | bool _discovering_refs; // true when discovery enabled |
aoqi@0 | 227 | bool _discovery_is_atomic; // if discovery is atomic wrt |
aoqi@0 | 228 | // other collectors in configuration |
aoqi@0 | 229 | bool _discovery_is_mt; // true if reference discovery is MT. |
aoqi@0 | 230 | |
aoqi@0 | 231 | bool _enqueuing_is_done; // true if all weak references enqueued |
aoqi@0 | 232 | bool _processing_is_mt; // true during phases when |
aoqi@0 | 233 | // reference processing is MT. |
aoqi@0 | 234 | uint _next_id; // round-robin mod _num_q counter in |
aoqi@0 | 235 | // support of work distribution |
aoqi@0 | 236 | |
aoqi@0 | 237 | // For collectors that do not keep GC liveness information |
aoqi@0 | 238 | // in the object header, this field holds a closure that |
aoqi@0 | 239 | // helps the reference processor determine the reachability |
aoqi@0 | 240 | // of an oop. It is currently initialized to NULL for all |
aoqi@0 | 241 | // collectors except for CMS and G1. |
aoqi@0 | 242 | BoolObjectClosure* _is_alive_non_header; |
aoqi@0 | 243 | |
aoqi@0 | 244 | // Soft ref clearing policies |
aoqi@0 | 245 | // . the default policy |
aoqi@0 | 246 | static ReferencePolicy* _default_soft_ref_policy; |
aoqi@0 | 247 | // . the "clear all" policy |
aoqi@0 | 248 | static ReferencePolicy* _always_clear_soft_ref_policy; |
aoqi@0 | 249 | // . the current policy below is either one of the above |
aoqi@0 | 250 | ReferencePolicy* _current_soft_ref_policy; |
aoqi@0 | 251 | |
aoqi@0 | 252 | // The discovered ref lists themselves |
aoqi@0 | 253 | |
aoqi@0 | 254 | // The active MT'ness degree of the queues below |
aoqi@0 | 255 | uint _num_q; |
aoqi@0 | 256 | // The maximum MT'ness degree of the queues below |
aoqi@0 | 257 | uint _max_num_q; |
aoqi@0 | 258 | |
aoqi@0 | 259 | // Master array of discovered oops |
aoqi@0 | 260 | DiscoveredList* _discovered_refs; |
aoqi@0 | 261 | |
aoqi@0 | 262 | // Arrays of lists of oops, one per thread (pointers into master array above) |
aoqi@0 | 263 | DiscoveredList* _discoveredSoftRefs; |
aoqi@0 | 264 | DiscoveredList* _discoveredWeakRefs; |
aoqi@0 | 265 | DiscoveredList* _discoveredFinalRefs; |
aoqi@0 | 266 | DiscoveredList* _discoveredPhantomRefs; |
jmasa@7469 | 267 | DiscoveredList* _discoveredCleanerRefs; |
aoqi@0 | 268 | |
aoqi@0 | 269 | public: |
jmasa@7469 | 270 | static int number_of_subclasses_of_ref() { return (REF_CLEANER - REF_OTHER); } |
aoqi@0 | 271 | |
aoqi@0 | 272 | uint num_q() { return _num_q; } |
aoqi@0 | 273 | uint max_num_q() { return _max_num_q; } |
aoqi@0 | 274 | void set_active_mt_degree(uint v) { _num_q = v; } |
aoqi@0 | 275 | |
aoqi@0 | 276 | DiscoveredList* discovered_refs() { return _discovered_refs; } |
aoqi@0 | 277 | |
aoqi@0 | 278 | ReferencePolicy* setup_policy(bool always_clear) { |
aoqi@0 | 279 | _current_soft_ref_policy = always_clear ? |
aoqi@0 | 280 | _always_clear_soft_ref_policy : _default_soft_ref_policy; |
aoqi@0 | 281 | _current_soft_ref_policy->setup(); // snapshot the policy threshold |
aoqi@0 | 282 | return _current_soft_ref_policy; |
aoqi@0 | 283 | } |
aoqi@0 | 284 | |
aoqi@0 | 285 | // Process references with a certain reachability level. |
aoqi@0 | 286 | size_t process_discovered_reflist(DiscoveredList refs_lists[], |
aoqi@0 | 287 | ReferencePolicy* policy, |
aoqi@0 | 288 | bool clear_referent, |
aoqi@0 | 289 | BoolObjectClosure* is_alive, |
aoqi@0 | 290 | OopClosure* keep_alive, |
aoqi@0 | 291 | VoidClosure* complete_gc, |
aoqi@0 | 292 | AbstractRefProcTaskExecutor* task_executor); |
aoqi@0 | 293 | |
aoqi@0 | 294 | void process_phaseJNI(BoolObjectClosure* is_alive, |
aoqi@0 | 295 | OopClosure* keep_alive, |
aoqi@0 | 296 | VoidClosure* complete_gc); |
aoqi@0 | 297 | |
aoqi@0 | 298 | // Work methods used by the method process_discovered_reflist |
aoqi@0 | 299 | // Phase1: keep alive all those referents that are otherwise |
aoqi@0 | 300 | // dead but which must be kept alive by policy (and their closure). |
aoqi@0 | 301 | void process_phase1(DiscoveredList& refs_list, |
aoqi@0 | 302 | ReferencePolicy* policy, |
aoqi@0 | 303 | BoolObjectClosure* is_alive, |
aoqi@0 | 304 | OopClosure* keep_alive, |
aoqi@0 | 305 | VoidClosure* complete_gc); |
aoqi@0 | 306 | // Phase2: remove all those references whose referents are |
aoqi@0 | 307 | // reachable. |
aoqi@0 | 308 | inline void process_phase2(DiscoveredList& refs_list, |
aoqi@0 | 309 | BoolObjectClosure* is_alive, |
aoqi@0 | 310 | OopClosure* keep_alive, |
aoqi@0 | 311 | VoidClosure* complete_gc) { |
aoqi@0 | 312 | if (discovery_is_atomic()) { |
aoqi@0 | 313 | // complete_gc is ignored in this case for this phase |
aoqi@0 | 314 | pp2_work(refs_list, is_alive, keep_alive); |
aoqi@0 | 315 | } else { |
aoqi@0 | 316 | assert(complete_gc != NULL, "Error"); |
aoqi@0 | 317 | pp2_work_concurrent_discovery(refs_list, is_alive, |
aoqi@0 | 318 | keep_alive, complete_gc); |
aoqi@0 | 319 | } |
aoqi@0 | 320 | } |
aoqi@0 | 321 | // Work methods in support of process_phase2 |
aoqi@0 | 322 | void pp2_work(DiscoveredList& refs_list, |
aoqi@0 | 323 | BoolObjectClosure* is_alive, |
aoqi@0 | 324 | OopClosure* keep_alive); |
aoqi@0 | 325 | void pp2_work_concurrent_discovery( |
aoqi@0 | 326 | DiscoveredList& refs_list, |
aoqi@0 | 327 | BoolObjectClosure* is_alive, |
aoqi@0 | 328 | OopClosure* keep_alive, |
aoqi@0 | 329 | VoidClosure* complete_gc); |
aoqi@0 | 330 | // Phase3: process the referents by either clearing them |
aoqi@0 | 331 | // or keeping them alive (and their closure) |
aoqi@0 | 332 | void process_phase3(DiscoveredList& refs_list, |
aoqi@0 | 333 | bool clear_referent, |
aoqi@0 | 334 | BoolObjectClosure* is_alive, |
aoqi@0 | 335 | OopClosure* keep_alive, |
aoqi@0 | 336 | VoidClosure* complete_gc); |
aoqi@0 | 337 | |
aoqi@0 | 338 | // Enqueue references with a certain reachability level |
aoqi@0 | 339 | void enqueue_discovered_reflist(DiscoveredList& refs_list, HeapWord* pending_list_addr); |
aoqi@0 | 340 | |
aoqi@0 | 341 | // "Preclean" all the discovered reference lists |
aoqi@0 | 342 | // by removing references with strongly reachable referents. |
aoqi@0 | 343 | // The first argument is a predicate on an oop that indicates |
aoqi@0 | 344 | // its (strong) reachability and the second is a closure that |
aoqi@0 | 345 | // may be used to incrementalize or abort the precleaning process. |
aoqi@0 | 346 | // The caller is responsible for taking care of potential |
aoqi@0 | 347 | // interference with concurrent operations on these lists |
aoqi@0 | 348 | // (or predicates involved) by other threads. Currently |
aoqi@0 | 349 | // only used by the CMS collector. |
aoqi@0 | 350 | void preclean_discovered_references(BoolObjectClosure* is_alive, |
aoqi@0 | 351 | OopClosure* keep_alive, |
aoqi@0 | 352 | VoidClosure* complete_gc, |
aoqi@0 | 353 | YieldClosure* yield, |
brutisso@6904 | 354 | GCTimer* gc_timer, |
brutisso@6904 | 355 | GCId gc_id); |
aoqi@0 | 356 | |
aoqi@0 | 357 | // Delete entries in the discovered lists that have |
aoqi@0 | 358 | // either a null referent or are not active. Such |
aoqi@0 | 359 | // Reference objects can result from the clearing |
aoqi@0 | 360 | // or enqueueing of Reference objects concurrent |
aoqi@0 | 361 | // with their discovery by a (concurrent) collector. |
aoqi@0 | 362 | // For a definition of "active" see java.lang.ref.Reference; |
aoqi@0 | 363 | // Refs are born active, become inactive when enqueued, |
aoqi@0 | 364 | // and never become active again. The state of being |
aoqi@0 | 365 | // active is encoded as follows: A Ref is active |
aoqi@0 | 366 | // if and only if its "next" field is NULL. |
aoqi@0 | 367 | void clean_up_discovered_references(); |
aoqi@0 | 368 | void clean_up_discovered_reflist(DiscoveredList& refs_list); |
aoqi@0 | 369 | |
aoqi@0 | 370 | // Returns the name of the discovered reference list |
aoqi@0 | 371 | // occupying the i / _num_q slot. |
aoqi@0 | 372 | const char* list_name(uint i); |
aoqi@0 | 373 | |
aoqi@0 | 374 | void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor); |
aoqi@0 | 375 | |
aoqi@0 | 376 | protected: |
aoqi@0 | 377 | // "Preclean" the given discovered reference list |
aoqi@0 | 378 | // by removing references with strongly reachable referents. |
aoqi@0 | 379 | // Currently used in support of CMS only. |
aoqi@0 | 380 | void preclean_discovered_reflist(DiscoveredList& refs_list, |
aoqi@0 | 381 | BoolObjectClosure* is_alive, |
aoqi@0 | 382 | OopClosure* keep_alive, |
aoqi@0 | 383 | VoidClosure* complete_gc, |
aoqi@0 | 384 | YieldClosure* yield); |
aoqi@0 | 385 | |
aoqi@0 | 386 | // round-robin mod _num_q (not: _not_ mode _max_num_q) |
aoqi@0 | 387 | uint next_id() { |
aoqi@0 | 388 | uint id = _next_id; |
aoqi@0 | 389 | if (++_next_id == _num_q) { |
aoqi@0 | 390 | _next_id = 0; |
aoqi@0 | 391 | } |
aoqi@0 | 392 | return id; |
aoqi@0 | 393 | } |
aoqi@0 | 394 | DiscoveredList* get_discovered_list(ReferenceType rt); |
aoqi@0 | 395 | inline void add_to_discovered_list_mt(DiscoveredList& refs_list, oop obj, |
aoqi@0 | 396 | HeapWord* discovered_addr); |
aoqi@0 | 397 | void verify_ok_to_handle_reflists() PRODUCT_RETURN; |
aoqi@0 | 398 | |
aoqi@0 | 399 | void clear_discovered_references(DiscoveredList& refs_list); |
aoqi@0 | 400 | void abandon_partial_discovered_list(DiscoveredList& refs_list); |
aoqi@0 | 401 | |
aoqi@0 | 402 | // Calculate the number of jni handles. |
aoqi@0 | 403 | unsigned int count_jni_refs(); |
aoqi@0 | 404 | |
aoqi@0 | 405 | // Balances reference queues. |
aoqi@0 | 406 | void balance_queues(DiscoveredList ref_lists[]); |
aoqi@0 | 407 | |
aoqi@0 | 408 | // Update (advance) the soft ref master clock field. |
aoqi@0 | 409 | void update_soft_ref_master_clock(); |
aoqi@0 | 410 | |
aoqi@0 | 411 | public: |
aoqi@0 | 412 | // Default parameters give you a vanilla reference processor. |
aoqi@0 | 413 | ReferenceProcessor(MemRegion span, |
aoqi@0 | 414 | bool mt_processing = false, uint mt_processing_degree = 1, |
aoqi@0 | 415 | bool mt_discovery = false, uint mt_discovery_degree = 1, |
aoqi@0 | 416 | bool atomic_discovery = true, |
aoqi@0 | 417 | BoolObjectClosure* is_alive_non_header = NULL); |
aoqi@0 | 418 | |
aoqi@0 | 419 | // RefDiscoveryPolicy values |
aoqi@0 | 420 | enum DiscoveryPolicy { |
aoqi@0 | 421 | ReferenceBasedDiscovery = 0, |
aoqi@0 | 422 | ReferentBasedDiscovery = 1, |
aoqi@0 | 423 | DiscoveryPolicyMin = ReferenceBasedDiscovery, |
aoqi@0 | 424 | DiscoveryPolicyMax = ReferentBasedDiscovery |
aoqi@0 | 425 | }; |
aoqi@0 | 426 | |
aoqi@0 | 427 | static void init_statics(); |
aoqi@0 | 428 | |
aoqi@0 | 429 | public: |
aoqi@0 | 430 | // get and set "is_alive_non_header" field |
aoqi@0 | 431 | BoolObjectClosure* is_alive_non_header() { |
aoqi@0 | 432 | return _is_alive_non_header; |
aoqi@0 | 433 | } |
aoqi@0 | 434 | void set_is_alive_non_header(BoolObjectClosure* is_alive_non_header) { |
aoqi@0 | 435 | _is_alive_non_header = is_alive_non_header; |
aoqi@0 | 436 | } |
aoqi@0 | 437 | |
aoqi@0 | 438 | // get and set span |
aoqi@0 | 439 | MemRegion span() { return _span; } |
aoqi@0 | 440 | void set_span(MemRegion span) { _span = span; } |
aoqi@0 | 441 | |
aoqi@0 | 442 | // start and stop weak ref discovery |
aoqi@0 | 443 | void enable_discovery(bool verify_disabled, bool check_no_refs); |
aoqi@0 | 444 | void disable_discovery() { _discovering_refs = false; } |
aoqi@0 | 445 | bool discovery_enabled() { return _discovering_refs; } |
aoqi@0 | 446 | |
aoqi@0 | 447 | // whether discovery is atomic wrt other collectors |
aoqi@0 | 448 | bool discovery_is_atomic() const { return _discovery_is_atomic; } |
aoqi@0 | 449 | void set_atomic_discovery(bool atomic) { _discovery_is_atomic = atomic; } |
aoqi@0 | 450 | |
aoqi@0 | 451 | // whether the JDK in which we are embedded is a pre-4965777 JDK, |
aoqi@0 | 452 | // and thus whether or not it uses the discovered field to chain |
aoqi@0 | 453 | // the entries in the pending list. |
aoqi@0 | 454 | static bool pending_list_uses_discovered_field() { |
aoqi@0 | 455 | return _pending_list_uses_discovered_field; |
aoqi@0 | 456 | } |
aoqi@0 | 457 | |
aoqi@0 | 458 | // whether discovery is done by multiple threads same-old-timeously |
aoqi@0 | 459 | bool discovery_is_mt() const { return _discovery_is_mt; } |
aoqi@0 | 460 | void set_mt_discovery(bool mt) { _discovery_is_mt = mt; } |
aoqi@0 | 461 | |
aoqi@0 | 462 | // Whether we are in a phase when _processing_ is MT. |
aoqi@0 | 463 | bool processing_is_mt() const { return _processing_is_mt; } |
aoqi@0 | 464 | void set_mt_processing(bool mt) { _processing_is_mt = mt; } |
aoqi@0 | 465 | |
aoqi@0 | 466 | // whether all enqueuing of weak references is complete |
aoqi@0 | 467 | bool enqueuing_is_done() { return _enqueuing_is_done; } |
aoqi@0 | 468 | void set_enqueuing_is_done(bool v) { _enqueuing_is_done = v; } |
aoqi@0 | 469 | |
aoqi@0 | 470 | // iterate over oops |
aoqi@0 | 471 | void weak_oops_do(OopClosure* f); // weak roots |
aoqi@0 | 472 | |
aoqi@0 | 473 | // Balance each of the discovered lists. |
aoqi@0 | 474 | void balance_all_queues(); |
aoqi@0 | 475 | void verify_list(DiscoveredList& ref_list); |
aoqi@0 | 476 | |
aoqi@0 | 477 | // Discover a Reference object, using appropriate discovery criteria |
aoqi@0 | 478 | bool discover_reference(oop obj, ReferenceType rt); |
aoqi@0 | 479 | |
aoqi@0 | 480 | // Process references found during GC (called by the garbage collector) |
aoqi@0 | 481 | ReferenceProcessorStats |
aoqi@0 | 482 | process_discovered_references(BoolObjectClosure* is_alive, |
aoqi@0 | 483 | OopClosure* keep_alive, |
aoqi@0 | 484 | VoidClosure* complete_gc, |
aoqi@0 | 485 | AbstractRefProcTaskExecutor* task_executor, |
brutisso@6904 | 486 | GCTimer *gc_timer, |
brutisso@6904 | 487 | GCId gc_id); |
aoqi@0 | 488 | |
aoqi@0 | 489 | // Enqueue references at end of GC (called by the garbage collector) |
aoqi@0 | 490 | bool enqueue_discovered_references(AbstractRefProcTaskExecutor* task_executor = NULL); |
aoqi@0 | 491 | |
aoqi@0 | 492 | // If a discovery is in process that is being superceded, abandon it: all |
aoqi@0 | 493 | // the discovered lists will be empty, and all the objects on them will |
aoqi@0 | 494 | // have NULL discovered fields. Must be called only at a safepoint. |
aoqi@0 | 495 | void abandon_partial_discovery(); |
aoqi@0 | 496 | |
aoqi@0 | 497 | // debugging |
aoqi@0 | 498 | void verify_no_references_recorded() PRODUCT_RETURN; |
aoqi@0 | 499 | void verify_referent(oop obj) PRODUCT_RETURN; |
aoqi@0 | 500 | |
aoqi@0 | 501 | // clear the discovered lists (unlinking each entry). |
aoqi@0 | 502 | void clear_discovered_references() PRODUCT_RETURN; |
aoqi@0 | 503 | }; |
aoqi@0 | 504 | |
aoqi@0 | 505 | // A utility class to disable reference discovery in |
aoqi@0 | 506 | // the scope which contains it, for given ReferenceProcessor. |
aoqi@0 | 507 | class NoRefDiscovery: StackObj { |
aoqi@0 | 508 | private: |
aoqi@0 | 509 | ReferenceProcessor* _rp; |
aoqi@0 | 510 | bool _was_discovering_refs; |
aoqi@0 | 511 | public: |
aoqi@0 | 512 | NoRefDiscovery(ReferenceProcessor* rp) : _rp(rp) { |
aoqi@0 | 513 | _was_discovering_refs = _rp->discovery_enabled(); |
aoqi@0 | 514 | if (_was_discovering_refs) { |
aoqi@0 | 515 | _rp->disable_discovery(); |
aoqi@0 | 516 | } |
aoqi@0 | 517 | } |
aoqi@0 | 518 | |
aoqi@0 | 519 | ~NoRefDiscovery() { |
aoqi@0 | 520 | if (_was_discovering_refs) { |
aoqi@0 | 521 | _rp->enable_discovery(true /*verify_disabled*/, false /*check_no_refs*/); |
aoqi@0 | 522 | } |
aoqi@0 | 523 | } |
aoqi@0 | 524 | }; |
aoqi@0 | 525 | |
aoqi@0 | 526 | |
aoqi@0 | 527 | // A utility class to temporarily mutate the span of the |
aoqi@0 | 528 | // given ReferenceProcessor in the scope that contains it. |
aoqi@0 | 529 | class ReferenceProcessorSpanMutator: StackObj { |
aoqi@0 | 530 | private: |
aoqi@0 | 531 | ReferenceProcessor* _rp; |
aoqi@0 | 532 | MemRegion _saved_span; |
aoqi@0 | 533 | |
aoqi@0 | 534 | public: |
aoqi@0 | 535 | ReferenceProcessorSpanMutator(ReferenceProcessor* rp, |
aoqi@0 | 536 | MemRegion span): |
aoqi@0 | 537 | _rp(rp) { |
aoqi@0 | 538 | _saved_span = _rp->span(); |
aoqi@0 | 539 | _rp->set_span(span); |
aoqi@0 | 540 | } |
aoqi@0 | 541 | |
aoqi@0 | 542 | ~ReferenceProcessorSpanMutator() { |
aoqi@0 | 543 | _rp->set_span(_saved_span); |
aoqi@0 | 544 | } |
aoqi@0 | 545 | }; |
aoqi@0 | 546 | |
aoqi@0 | 547 | // A utility class to temporarily change the MT'ness of |
aoqi@0 | 548 | // reference discovery for the given ReferenceProcessor |
aoqi@0 | 549 | // in the scope that contains it. |
aoqi@0 | 550 | class ReferenceProcessorMTDiscoveryMutator: StackObj { |
aoqi@0 | 551 | private: |
aoqi@0 | 552 | ReferenceProcessor* _rp; |
aoqi@0 | 553 | bool _saved_mt; |
aoqi@0 | 554 | |
aoqi@0 | 555 | public: |
aoqi@0 | 556 | ReferenceProcessorMTDiscoveryMutator(ReferenceProcessor* rp, |
aoqi@0 | 557 | bool mt): |
aoqi@0 | 558 | _rp(rp) { |
aoqi@0 | 559 | _saved_mt = _rp->discovery_is_mt(); |
aoqi@0 | 560 | _rp->set_mt_discovery(mt); |
aoqi@0 | 561 | } |
aoqi@0 | 562 | |
aoqi@0 | 563 | ~ReferenceProcessorMTDiscoveryMutator() { |
aoqi@0 | 564 | _rp->set_mt_discovery(_saved_mt); |
aoqi@0 | 565 | } |
aoqi@0 | 566 | }; |
aoqi@0 | 567 | |
aoqi@0 | 568 | |
aoqi@0 | 569 | // A utility class to temporarily change the disposition |
aoqi@0 | 570 | // of the "is_alive_non_header" closure field of the |
aoqi@0 | 571 | // given ReferenceProcessor in the scope that contains it. |
aoqi@0 | 572 | class ReferenceProcessorIsAliveMutator: StackObj { |
aoqi@0 | 573 | private: |
aoqi@0 | 574 | ReferenceProcessor* _rp; |
aoqi@0 | 575 | BoolObjectClosure* _saved_cl; |
aoqi@0 | 576 | |
aoqi@0 | 577 | public: |
aoqi@0 | 578 | ReferenceProcessorIsAliveMutator(ReferenceProcessor* rp, |
aoqi@0 | 579 | BoolObjectClosure* cl): |
aoqi@0 | 580 | _rp(rp) { |
aoqi@0 | 581 | _saved_cl = _rp->is_alive_non_header(); |
aoqi@0 | 582 | _rp->set_is_alive_non_header(cl); |
aoqi@0 | 583 | } |
aoqi@0 | 584 | |
aoqi@0 | 585 | ~ReferenceProcessorIsAliveMutator() { |
aoqi@0 | 586 | _rp->set_is_alive_non_header(_saved_cl); |
aoqi@0 | 587 | } |
aoqi@0 | 588 | }; |
aoqi@0 | 589 | |
aoqi@0 | 590 | // A utility class to temporarily change the disposition |
aoqi@0 | 591 | // of the "discovery_is_atomic" field of the |
aoqi@0 | 592 | // given ReferenceProcessor in the scope that contains it. |
aoqi@0 | 593 | class ReferenceProcessorAtomicMutator: StackObj { |
aoqi@0 | 594 | private: |
aoqi@0 | 595 | ReferenceProcessor* _rp; |
aoqi@0 | 596 | bool _saved_atomic_discovery; |
aoqi@0 | 597 | |
aoqi@0 | 598 | public: |
aoqi@0 | 599 | ReferenceProcessorAtomicMutator(ReferenceProcessor* rp, |
aoqi@0 | 600 | bool atomic): |
aoqi@0 | 601 | _rp(rp) { |
aoqi@0 | 602 | _saved_atomic_discovery = _rp->discovery_is_atomic(); |
aoqi@0 | 603 | _rp->set_atomic_discovery(atomic); |
aoqi@0 | 604 | } |
aoqi@0 | 605 | |
aoqi@0 | 606 | ~ReferenceProcessorAtomicMutator() { |
aoqi@0 | 607 | _rp->set_atomic_discovery(_saved_atomic_discovery); |
aoqi@0 | 608 | } |
aoqi@0 | 609 | }; |
aoqi@0 | 610 | |
aoqi@0 | 611 | |
aoqi@0 | 612 | // A utility class to temporarily change the MT processing |
aoqi@0 | 613 | // disposition of the given ReferenceProcessor instance |
aoqi@0 | 614 | // in the scope that contains it. |
aoqi@0 | 615 | class ReferenceProcessorMTProcMutator: StackObj { |
aoqi@0 | 616 | private: |
aoqi@0 | 617 | ReferenceProcessor* _rp; |
aoqi@0 | 618 | bool _saved_mt; |
aoqi@0 | 619 | |
aoqi@0 | 620 | public: |
aoqi@0 | 621 | ReferenceProcessorMTProcMutator(ReferenceProcessor* rp, |
aoqi@0 | 622 | bool mt): |
aoqi@0 | 623 | _rp(rp) { |
aoqi@0 | 624 | _saved_mt = _rp->processing_is_mt(); |
aoqi@0 | 625 | _rp->set_mt_processing(mt); |
aoqi@0 | 626 | } |
aoqi@0 | 627 | |
aoqi@0 | 628 | ~ReferenceProcessorMTProcMutator() { |
aoqi@0 | 629 | _rp->set_mt_processing(_saved_mt); |
aoqi@0 | 630 | } |
aoqi@0 | 631 | }; |
aoqi@0 | 632 | |
aoqi@0 | 633 | |
aoqi@0 | 634 | // This class is an interface used to implement task execution for the |
aoqi@0 | 635 | // reference processing. |
aoqi@0 | 636 | class AbstractRefProcTaskExecutor { |
aoqi@0 | 637 | public: |
aoqi@0 | 638 | |
aoqi@0 | 639 | // Abstract tasks to execute. |
aoqi@0 | 640 | class ProcessTask; |
aoqi@0 | 641 | class EnqueueTask; |
aoqi@0 | 642 | |
aoqi@0 | 643 | // Executes a task using worker threads. |
aoqi@0 | 644 | virtual void execute(ProcessTask& task) = 0; |
aoqi@0 | 645 | virtual void execute(EnqueueTask& task) = 0; |
aoqi@0 | 646 | |
aoqi@0 | 647 | // Switch to single threaded mode. |
aoqi@0 | 648 | virtual void set_single_threaded_mode() { }; |
aoqi@0 | 649 | }; |
aoqi@0 | 650 | |
aoqi@0 | 651 | // Abstract reference processing task to execute. |
aoqi@0 | 652 | class AbstractRefProcTaskExecutor::ProcessTask { |
aoqi@0 | 653 | protected: |
aoqi@0 | 654 | ProcessTask(ReferenceProcessor& ref_processor, |
aoqi@0 | 655 | DiscoveredList refs_lists[], |
aoqi@0 | 656 | bool marks_oops_alive) |
aoqi@0 | 657 | : _ref_processor(ref_processor), |
aoqi@0 | 658 | _refs_lists(refs_lists), |
aoqi@0 | 659 | _marks_oops_alive(marks_oops_alive) |
aoqi@0 | 660 | { } |
aoqi@0 | 661 | |
aoqi@0 | 662 | public: |
aoqi@0 | 663 | virtual void work(unsigned int work_id, BoolObjectClosure& is_alive, |
aoqi@0 | 664 | OopClosure& keep_alive, |
aoqi@0 | 665 | VoidClosure& complete_gc) = 0; |
aoqi@0 | 666 | |
aoqi@0 | 667 | // Returns true if a task marks some oops as alive. |
aoqi@0 | 668 | bool marks_oops_alive() const |
aoqi@0 | 669 | { return _marks_oops_alive; } |
aoqi@0 | 670 | |
aoqi@0 | 671 | protected: |
aoqi@0 | 672 | ReferenceProcessor& _ref_processor; |
aoqi@0 | 673 | DiscoveredList* _refs_lists; |
aoqi@0 | 674 | const bool _marks_oops_alive; |
aoqi@0 | 675 | }; |
aoqi@0 | 676 | |
aoqi@0 | 677 | // Abstract reference processing task to execute. |
aoqi@0 | 678 | class AbstractRefProcTaskExecutor::EnqueueTask { |
aoqi@0 | 679 | protected: |
aoqi@0 | 680 | EnqueueTask(ReferenceProcessor& ref_processor, |
aoqi@0 | 681 | DiscoveredList refs_lists[], |
aoqi@0 | 682 | HeapWord* pending_list_addr, |
aoqi@0 | 683 | int n_queues) |
aoqi@0 | 684 | : _ref_processor(ref_processor), |
aoqi@0 | 685 | _refs_lists(refs_lists), |
aoqi@0 | 686 | _pending_list_addr(pending_list_addr), |
aoqi@0 | 687 | _n_queues(n_queues) |
aoqi@0 | 688 | { } |
aoqi@0 | 689 | |
aoqi@0 | 690 | public: |
aoqi@0 | 691 | virtual void work(unsigned int work_id) = 0; |
aoqi@0 | 692 | |
aoqi@0 | 693 | protected: |
aoqi@0 | 694 | ReferenceProcessor& _ref_processor; |
aoqi@0 | 695 | DiscoveredList* _refs_lists; |
aoqi@0 | 696 | HeapWord* _pending_list_addr; |
aoqi@0 | 697 | int _n_queues; |
aoqi@0 | 698 | }; |
aoqi@0 | 699 | |
aoqi@0 | 700 | #endif // SHARE_VM_MEMORY_REFERENCEPROCESSOR_HPP |