Wed, 26 Jun 2013 16:58:37 +0200
8013590: NPG: Add a memory pool MXBean for Metaspace
Reviewed-by: jmasa, mgerdin
duke@435 | 1 | /* |
sla@5237 | 2 | * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #ifndef SHARE_VM_MEMORY_REFERENCEPROCESSOR_HPP |
stefank@2314 | 26 | #define SHARE_VM_MEMORY_REFERENCEPROCESSOR_HPP |
stefank@2314 | 27 | |
stefank@2314 | 28 | #include "memory/referencePolicy.hpp" |
sla@5237 | 29 | #include "memory/referenceProcessorStats.hpp" |
sla@5237 | 30 | #include "memory/referenceType.hpp" |
stefank@2314 | 31 | #include "oops/instanceRefKlass.hpp" |
stefank@2314 | 32 | |
sla@5237 | 33 | class GCTimer; |
sla@5237 | 34 | |
duke@435 | 35 | // ReferenceProcessor class encapsulates the per-"collector" processing |
ysr@888 | 36 | // of java.lang.Reference objects for GC. The interface is useful for supporting |
duke@435 | 37 | // a generational abstraction, in particular when there are multiple |
duke@435 | 38 | // generations that are being independently collected -- possibly |
duke@435 | 39 | // concurrently and/or incrementally. Note, however, that the |
duke@435 | 40 | // ReferenceProcessor class abstracts away from a generational setting |
duke@435 | 41 | // by using only a heap interval (called "span" below), thus allowing |
duke@435 | 42 | // its use in a straightforward manner in a general, non-generational |
duke@435 | 43 | // setting. |
duke@435 | 44 | // |
duke@435 | 45 | // The basic idea is that each ReferenceProcessor object concerns |
duke@435 | 46 | // itself with ("weak") reference processing in a specific "span" |
duke@435 | 47 | // of the heap of interest to a specific collector. Currently, |
duke@435 | 48 | // the span is a convex interval of the heap, but, efficiency |
duke@435 | 49 | // apart, there seems to be no reason it couldn't be extended |
duke@435 | 50 | // (with appropriate modifications) to any "non-convex interval". |
duke@435 | 51 | |
duke@435 | 52 | // forward references |
duke@435 | 53 | class ReferencePolicy; |
duke@435 | 54 | class AbstractRefProcTaskExecutor; |
johnc@3175 | 55 | |
johnc@3175 | 56 | // List of discovered references. |
johnc@3175 | 57 | class DiscoveredList { |
johnc@3175 | 58 | public: |
johnc@3175 | 59 | DiscoveredList() : _len(0), _compressed_head(0), _oop_head(NULL) { } |
johnc@3175 | 60 | oop head() const { |
johnc@3175 | 61 | return UseCompressedOops ? oopDesc::decode_heap_oop(_compressed_head) : |
johnc@3175 | 62 | _oop_head; |
johnc@3175 | 63 | } |
johnc@3175 | 64 | HeapWord* adr_head() { |
johnc@3175 | 65 | return UseCompressedOops ? (HeapWord*)&_compressed_head : |
johnc@3175 | 66 | (HeapWord*)&_oop_head; |
johnc@3175 | 67 | } |
johnc@3175 | 68 | void set_head(oop o) { |
johnc@3175 | 69 | if (UseCompressedOops) { |
johnc@3175 | 70 | // Must compress the head ptr. |
johnc@3175 | 71 | _compressed_head = oopDesc::encode_heap_oop(o); |
johnc@3175 | 72 | } else { |
johnc@3175 | 73 | _oop_head = o; |
johnc@3175 | 74 | } |
johnc@3175 | 75 | } |
johnc@3175 | 76 | bool is_empty() const { return head() == NULL; } |
johnc@3175 | 77 | size_t length() { return _len; } |
johnc@3175 | 78 | void set_length(size_t len) { _len = len; } |
johnc@3175 | 79 | void inc_length(size_t inc) { _len += inc; assert(_len > 0, "Error"); } |
johnc@3175 | 80 | void dec_length(size_t dec) { _len -= dec; } |
johnc@3175 | 81 | private: |
johnc@3175 | 82 | // Set value depending on UseCompressedOops. This could be a template class |
johnc@3175 | 83 | // but then we have to fix all the instantiations and declarations that use this class. |
johnc@3175 | 84 | oop _oop_head; |
johnc@3175 | 85 | narrowOop _compressed_head; |
johnc@3175 | 86 | size_t _len; |
johnc@3175 | 87 | }; |
johnc@3175 | 88 | |
johnc@3175 | 89 | // Iterator for the list of discovered references. |
johnc@3175 | 90 | class DiscoveredListIterator { |
johnc@3175 | 91 | private: |
johnc@3175 | 92 | DiscoveredList& _refs_list; |
johnc@3175 | 93 | HeapWord* _prev_next; |
johnc@3175 | 94 | oop _prev; |
johnc@3175 | 95 | oop _ref; |
johnc@3175 | 96 | HeapWord* _discovered_addr; |
johnc@3175 | 97 | oop _next; |
johnc@3175 | 98 | HeapWord* _referent_addr; |
johnc@3175 | 99 | oop _referent; |
johnc@3175 | 100 | OopClosure* _keep_alive; |
johnc@3175 | 101 | BoolObjectClosure* _is_alive; |
johnc@3175 | 102 | |
johnc@3175 | 103 | DEBUG_ONLY( |
johnc@3175 | 104 | oop _first_seen; // cyclic linked list check |
johnc@3175 | 105 | ) |
johnc@3175 | 106 | |
johnc@3175 | 107 | NOT_PRODUCT( |
johnc@3175 | 108 | size_t _processed; |
johnc@3175 | 109 | size_t _removed; |
johnc@3175 | 110 | ) |
johnc@3175 | 111 | |
johnc@3175 | 112 | public: |
johnc@3175 | 113 | inline DiscoveredListIterator(DiscoveredList& refs_list, |
johnc@3175 | 114 | OopClosure* keep_alive, |
johnc@3175 | 115 | BoolObjectClosure* is_alive): |
johnc@3175 | 116 | _refs_list(refs_list), |
johnc@3175 | 117 | _prev_next(refs_list.adr_head()), |
johnc@3175 | 118 | _prev(NULL), |
johnc@3175 | 119 | _ref(refs_list.head()), |
johnc@3175 | 120 | #ifdef ASSERT |
johnc@3175 | 121 | _first_seen(refs_list.head()), |
johnc@3175 | 122 | #endif |
johnc@3175 | 123 | #ifndef PRODUCT |
johnc@3175 | 124 | _processed(0), |
johnc@3175 | 125 | _removed(0), |
johnc@3175 | 126 | #endif |
johnc@3175 | 127 | _next(NULL), |
johnc@3175 | 128 | _keep_alive(keep_alive), |
johnc@3175 | 129 | _is_alive(is_alive) |
johnc@3175 | 130 | { } |
johnc@3175 | 131 | |
johnc@3175 | 132 | // End Of List. |
johnc@3175 | 133 | inline bool has_next() const { return _ref != NULL; } |
johnc@3175 | 134 | |
johnc@3175 | 135 | // Get oop to the Reference object. |
johnc@3175 | 136 | inline oop obj() const { return _ref; } |
johnc@3175 | 137 | |
johnc@3175 | 138 | // Get oop to the referent object. |
johnc@3175 | 139 | inline oop referent() const { return _referent; } |
johnc@3175 | 140 | |
johnc@3175 | 141 | // Returns true if referent is alive. |
johnc@3175 | 142 | inline bool is_referent_alive() const { |
johnc@3175 | 143 | return _is_alive->do_object_b(_referent); |
johnc@3175 | 144 | } |
johnc@3175 | 145 | |
johnc@3175 | 146 | // Loads data for the current reference. |
johnc@3175 | 147 | // The "allow_null_referent" argument tells us to allow for the possibility |
johnc@3175 | 148 | // of a NULL referent in the discovered Reference object. This typically |
johnc@3175 | 149 | // happens in the case of concurrent collectors that may have done the |
johnc@3175 | 150 | // discovery concurrently, or interleaved, with mutator execution. |
johnc@3175 | 151 | void load_ptrs(DEBUG_ONLY(bool allow_null_referent)); |
johnc@3175 | 152 | |
johnc@3175 | 153 | // Move to the next discovered reference. |
johnc@3175 | 154 | inline void next() { |
johnc@3175 | 155 | _prev_next = _discovered_addr; |
johnc@3175 | 156 | _prev = _ref; |
johnc@3175 | 157 | move_to_next(); |
johnc@3175 | 158 | } |
johnc@3175 | 159 | |
johnc@3175 | 160 | // Remove the current reference from the list |
johnc@3175 | 161 | void remove(); |
johnc@3175 | 162 | |
johnc@3175 | 163 | // Make the Reference object active again. |
johnc@3175 | 164 | void make_active(); |
johnc@3175 | 165 | |
johnc@3175 | 166 | // Make the referent alive. |
johnc@3175 | 167 | inline void make_referent_alive() { |
johnc@3175 | 168 | if (UseCompressedOops) { |
johnc@3175 | 169 | _keep_alive->do_oop((narrowOop*)_referent_addr); |
johnc@3175 | 170 | } else { |
johnc@3175 | 171 | _keep_alive->do_oop((oop*)_referent_addr); |
johnc@3175 | 172 | } |
johnc@3175 | 173 | } |
johnc@3175 | 174 | |
johnc@3175 | 175 | // Update the discovered field. |
johnc@3175 | 176 | inline void update_discovered() { |
johnc@3175 | 177 | // First _prev_next ref actually points into DiscoveredList (gross). |
johnc@3175 | 178 | if (UseCompressedOops) { |
johnc@3175 | 179 | if (!oopDesc::is_null(*(narrowOop*)_prev_next)) { |
johnc@3175 | 180 | _keep_alive->do_oop((narrowOop*)_prev_next); |
johnc@3175 | 181 | } |
johnc@3175 | 182 | } else { |
johnc@3175 | 183 | if (!oopDesc::is_null(*(oop*)_prev_next)) { |
johnc@3175 | 184 | _keep_alive->do_oop((oop*)_prev_next); |
johnc@3175 | 185 | } |
johnc@3175 | 186 | } |
johnc@3175 | 187 | } |
johnc@3175 | 188 | |
johnc@3175 | 189 | // NULL out referent pointer. |
johnc@3175 | 190 | void clear_referent(); |
johnc@3175 | 191 | |
johnc@3175 | 192 | // Statistics |
johnc@3175 | 193 | NOT_PRODUCT( |
johnc@3175 | 194 | inline size_t processed() const { return _processed; } |
johnc@3175 | 195 | inline size_t removed() const { return _removed; } |
johnc@3175 | 196 | ) |
johnc@3175 | 197 | |
johnc@3175 | 198 | inline void move_to_next() { |
johnc@3175 | 199 | if (_ref == _next) { |
johnc@3175 | 200 | // End of the list. |
johnc@3175 | 201 | _ref = NULL; |
johnc@3175 | 202 | } else { |
johnc@3175 | 203 | _ref = _next; |
johnc@3175 | 204 | } |
johnc@3175 | 205 | assert(_ref != _first_seen, "cyclic ref_list found"); |
johnc@3175 | 206 | NOT_PRODUCT(_processed++); |
johnc@3175 | 207 | } |
johnc@3175 | 208 | }; |
duke@435 | 209 | |
zgu@3900 | 210 | class ReferenceProcessor : public CHeapObj<mtGC> { |
sla@5237 | 211 | |
sla@5237 | 212 | private: |
sla@5237 | 213 | size_t total_count(DiscoveredList lists[]); |
sla@5237 | 214 | |
duke@435 | 215 | protected: |
ysr@3117 | 216 | // Compatibility with pre-4965777 JDK's |
ysr@3117 | 217 | static bool _pending_list_uses_discovered_field; |
johnc@3175 | 218 | |
johnc@3188 | 219 | // The SoftReference master timestamp clock |
johnc@3188 | 220 | static jlong _soft_ref_timestamp_clock; |
johnc@3188 | 221 | |
johnc@3175 | 222 | MemRegion _span; // (right-open) interval of heap |
johnc@3175 | 223 | // subject to wkref discovery |
johnc@3175 | 224 | |
johnc@3175 | 225 | bool _discovering_refs; // true when discovery enabled |
johnc@3175 | 226 | bool _discovery_is_atomic; // if discovery is atomic wrt |
johnc@3175 | 227 | // other collectors in configuration |
johnc@3175 | 228 | bool _discovery_is_mt; // true if reference discovery is MT. |
johnc@3175 | 229 | |
ysr@777 | 230 | // If true, setting "next" field of a discovered refs list requires |
ysr@777 | 231 | // write barrier(s). (Must be true if used in a collector in which |
ysr@777 | 232 | // elements of a discovered list may be moved during discovery: for |
ysr@777 | 233 | // example, a collector like Garbage-First that moves objects during a |
ysr@777 | 234 | // long-term concurrent marking phase that does weak reference |
ysr@777 | 235 | // discovery.) |
ysr@777 | 236 | bool _discovered_list_needs_barrier; |
duke@435 | 237 | |
johnc@3175 | 238 | BarrierSet* _bs; // Cached copy of BarrierSet. |
johnc@3175 | 239 | bool _enqueuing_is_done; // true if all weak references enqueued |
johnc@3175 | 240 | bool _processing_is_mt; // true during phases when |
johnc@3175 | 241 | // reference processing is MT. |
jmasa@3357 | 242 | uint _next_id; // round-robin mod _num_q counter in |
johnc@3175 | 243 | // support of work distribution |
johnc@3175 | 244 | |
johnc@3175 | 245 | // For collectors that do not keep GC liveness information |
duke@435 | 246 | // in the object header, this field holds a closure that |
duke@435 | 247 | // helps the reference processor determine the reachability |
johnc@3175 | 248 | // of an oop. It is currently initialized to NULL for all |
johnc@3175 | 249 | // collectors except for CMS and G1. |
duke@435 | 250 | BoolObjectClosure* _is_alive_non_header; |
duke@435 | 251 | |
ysr@888 | 252 | // Soft ref clearing policies |
ysr@888 | 253 | // . the default policy |
ysr@888 | 254 | static ReferencePolicy* _default_soft_ref_policy; |
ysr@888 | 255 | // . the "clear all" policy |
ysr@888 | 256 | static ReferencePolicy* _always_clear_soft_ref_policy; |
ysr@888 | 257 | // . the current policy below is either one of the above |
ysr@888 | 258 | ReferencePolicy* _current_soft_ref_policy; |
ysr@888 | 259 | |
duke@435 | 260 | // The discovered ref lists themselves |
coleenp@548 | 261 | |
jmasa@2188 | 262 | // The active MT'ness degree of the queues below |
jmasa@3357 | 263 | uint _num_q; |
jmasa@2188 | 264 | // The maximum MT'ness degree of the queues below |
jmasa@3357 | 265 | uint _max_num_q; |
johnc@3210 | 266 | |
johnc@3210 | 267 | // Master array of discovered oops |
johnc@3210 | 268 | DiscoveredList* _discovered_refs; |
johnc@3210 | 269 | |
johnc@3210 | 270 | // Arrays of lists of oops, one per thread (pointers into master array above) |
coleenp@548 | 271 | DiscoveredList* _discoveredSoftRefs; |
duke@435 | 272 | DiscoveredList* _discoveredWeakRefs; |
duke@435 | 273 | DiscoveredList* _discoveredFinalRefs; |
duke@435 | 274 | DiscoveredList* _discoveredPhantomRefs; |
duke@435 | 275 | |
duke@435 | 276 | public: |
johnc@3175 | 277 | static int number_of_subclasses_of_ref() { return (REF_PHANTOM - REF_OTHER); } |
johnc@3175 | 278 | |
jmasa@3357 | 279 | uint num_q() { return _num_q; } |
jmasa@3357 | 280 | uint max_num_q() { return _max_num_q; } |
jmasa@3357 | 281 | void set_active_mt_degree(uint v) { _num_q = v; } |
johnc@3210 | 282 | |
johnc@3210 | 283 | DiscoveredList* discovered_refs() { return _discovered_refs; } |
johnc@3175 | 284 | |
ysr@892 | 285 | ReferencePolicy* setup_policy(bool always_clear) { |
ysr@888 | 286 | _current_soft_ref_policy = always_clear ? |
ysr@888 | 287 | _always_clear_soft_ref_policy : _default_soft_ref_policy; |
ysr@892 | 288 | _current_soft_ref_policy->setup(); // snapshot the policy threshold |
ysr@888 | 289 | return _current_soft_ref_policy; |
ysr@888 | 290 | } |
duke@435 | 291 | |
duke@435 | 292 | // Process references with a certain reachability level. |
sla@5237 | 293 | size_t process_discovered_reflist(DiscoveredList refs_lists[], |
sla@5237 | 294 | ReferencePolicy* policy, |
sla@5237 | 295 | bool clear_referent, |
sla@5237 | 296 | BoolObjectClosure* is_alive, |
sla@5237 | 297 | OopClosure* keep_alive, |
sla@5237 | 298 | VoidClosure* complete_gc, |
sla@5237 | 299 | AbstractRefProcTaskExecutor* task_executor); |
duke@435 | 300 | |
duke@435 | 301 | void process_phaseJNI(BoolObjectClosure* is_alive, |
duke@435 | 302 | OopClosure* keep_alive, |
duke@435 | 303 | VoidClosure* complete_gc); |
duke@435 | 304 | |
duke@435 | 305 | // Work methods used by the method process_discovered_reflist |
duke@435 | 306 | // Phase1: keep alive all those referents that are otherwise |
duke@435 | 307 | // dead but which must be kept alive by policy (and their closure). |
coleenp@548 | 308 | void process_phase1(DiscoveredList& refs_list, |
duke@435 | 309 | ReferencePolicy* policy, |
duke@435 | 310 | BoolObjectClosure* is_alive, |
duke@435 | 311 | OopClosure* keep_alive, |
duke@435 | 312 | VoidClosure* complete_gc); |
duke@435 | 313 | // Phase2: remove all those references whose referents are |
duke@435 | 314 | // reachable. |
coleenp@548 | 315 | inline void process_phase2(DiscoveredList& refs_list, |
duke@435 | 316 | BoolObjectClosure* is_alive, |
duke@435 | 317 | OopClosure* keep_alive, |
duke@435 | 318 | VoidClosure* complete_gc) { |
duke@435 | 319 | if (discovery_is_atomic()) { |
duke@435 | 320 | // complete_gc is ignored in this case for this phase |
coleenp@548 | 321 | pp2_work(refs_list, is_alive, keep_alive); |
duke@435 | 322 | } else { |
duke@435 | 323 | assert(complete_gc != NULL, "Error"); |
coleenp@548 | 324 | pp2_work_concurrent_discovery(refs_list, is_alive, |
duke@435 | 325 | keep_alive, complete_gc); |
duke@435 | 326 | } |
duke@435 | 327 | } |
duke@435 | 328 | // Work methods in support of process_phase2 |
coleenp@548 | 329 | void pp2_work(DiscoveredList& refs_list, |
duke@435 | 330 | BoolObjectClosure* is_alive, |
duke@435 | 331 | OopClosure* keep_alive); |
duke@435 | 332 | void pp2_work_concurrent_discovery( |
coleenp@548 | 333 | DiscoveredList& refs_list, |
duke@435 | 334 | BoolObjectClosure* is_alive, |
duke@435 | 335 | OopClosure* keep_alive, |
duke@435 | 336 | VoidClosure* complete_gc); |
duke@435 | 337 | // Phase3: process the referents by either clearing them |
duke@435 | 338 | // or keeping them alive (and their closure) |
coleenp@548 | 339 | void process_phase3(DiscoveredList& refs_list, |
duke@435 | 340 | bool clear_referent, |
duke@435 | 341 | BoolObjectClosure* is_alive, |
duke@435 | 342 | OopClosure* keep_alive, |
duke@435 | 343 | VoidClosure* complete_gc); |
duke@435 | 344 | |
duke@435 | 345 | // Enqueue references with a certain reachability level |
coleenp@548 | 346 | void enqueue_discovered_reflist(DiscoveredList& refs_list, HeapWord* pending_list_addr); |
duke@435 | 347 | |
duke@435 | 348 | // "Preclean" all the discovered reference lists |
duke@435 | 349 | // by removing references with strongly reachable referents. |
duke@435 | 350 | // The first argument is a predicate on an oop that indicates |
duke@435 | 351 | // its (strong) reachability and the second is a closure that |
duke@435 | 352 | // may be used to incrementalize or abort the precleaning process. |
duke@435 | 353 | // The caller is responsible for taking care of potential |
duke@435 | 354 | // interference with concurrent operations on these lists |
duke@435 | 355 | // (or predicates involved) by other threads. Currently |
coleenp@4037 | 356 | // only used by the CMS collector. |
duke@435 | 357 | void preclean_discovered_references(BoolObjectClosure* is_alive, |
duke@435 | 358 | OopClosure* keep_alive, |
duke@435 | 359 | VoidClosure* complete_gc, |
sla@5237 | 360 | YieldClosure* yield, |
sla@5237 | 361 | GCTimer* gc_timer); |
duke@435 | 362 | |
duke@435 | 363 | // Delete entries in the discovered lists that have |
duke@435 | 364 | // either a null referent or are not active. Such |
duke@435 | 365 | // Reference objects can result from the clearing |
duke@435 | 366 | // or enqueueing of Reference objects concurrent |
duke@435 | 367 | // with their discovery by a (concurrent) collector. |
duke@435 | 368 | // For a definition of "active" see java.lang.ref.Reference; |
duke@435 | 369 | // Refs are born active, become inactive when enqueued, |
duke@435 | 370 | // and never become active again. The state of being |
duke@435 | 371 | // active is encoded as follows: A Ref is active |
duke@435 | 372 | // if and only if its "next" field is NULL. |
duke@435 | 373 | void clean_up_discovered_references(); |
duke@435 | 374 | void clean_up_discovered_reflist(DiscoveredList& refs_list); |
duke@435 | 375 | |
duke@435 | 376 | // Returns the name of the discovered reference list |
duke@435 | 377 | // occupying the i / _num_q slot. |
jmasa@3357 | 378 | const char* list_name(uint i); |
duke@435 | 379 | |
coleenp@548 | 380 | void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor); |
coleenp@548 | 381 | |
duke@435 | 382 | protected: |
johnc@3175 | 383 | // Set the 'discovered' field of the given reference to |
johnc@3175 | 384 | // the given value - emitting barriers depending upon |
johnc@3175 | 385 | // the value of _discovered_list_needs_barrier. |
johnc@3175 | 386 | void set_discovered(oop ref, oop value); |
johnc@3175 | 387 | |
duke@435 | 388 | // "Preclean" the given discovered reference list |
duke@435 | 389 | // by removing references with strongly reachable referents. |
duke@435 | 390 | // Currently used in support of CMS only. |
duke@435 | 391 | void preclean_discovered_reflist(DiscoveredList& refs_list, |
duke@435 | 392 | BoolObjectClosure* is_alive, |
duke@435 | 393 | OopClosure* keep_alive, |
duke@435 | 394 | VoidClosure* complete_gc, |
duke@435 | 395 | YieldClosure* yield); |
duke@435 | 396 | |
ysr@2651 | 397 | // round-robin mod _num_q (not: _not_ mode _max_num_q) |
jmasa@3357 | 398 | uint next_id() { |
jmasa@3357 | 399 | uint id = _next_id; |
duke@435 | 400 | if (++_next_id == _num_q) { |
duke@435 | 401 | _next_id = 0; |
duke@435 | 402 | } |
duke@435 | 403 | return id; |
duke@435 | 404 | } |
duke@435 | 405 | DiscoveredList* get_discovered_list(ReferenceType rt); |
duke@435 | 406 | inline void add_to_discovered_list_mt(DiscoveredList& refs_list, oop obj, |
coleenp@548 | 407 | HeapWord* discovered_addr); |
duke@435 | 408 | void verify_ok_to_handle_reflists() PRODUCT_RETURN; |
duke@435 | 409 | |
stefank@3115 | 410 | void clear_discovered_references(DiscoveredList& refs_list); |
duke@435 | 411 | void abandon_partial_discovered_list(DiscoveredList& refs_list); |
duke@435 | 412 | |
duke@435 | 413 | // Calculate the number of jni handles. |
duke@435 | 414 | unsigned int count_jni_refs(); |
duke@435 | 415 | |
duke@435 | 416 | // Balances reference queues. |
duke@435 | 417 | void balance_queues(DiscoveredList ref_lists[]); |
duke@435 | 418 | |
duke@435 | 419 | // Update (advance) the soft ref master clock field. |
duke@435 | 420 | void update_soft_ref_master_clock(); |
duke@435 | 421 | |
duke@435 | 422 | public: |
duke@435 | 423 | // constructor |
duke@435 | 424 | ReferenceProcessor(): |
duke@435 | 425 | _span((HeapWord*)NULL, (HeapWord*)NULL), |
johnc@3210 | 426 | _discovered_refs(NULL), |
duke@435 | 427 | _discoveredSoftRefs(NULL), _discoveredWeakRefs(NULL), |
duke@435 | 428 | _discoveredFinalRefs(NULL), _discoveredPhantomRefs(NULL), |
duke@435 | 429 | _discovering_refs(false), |
duke@435 | 430 | _discovery_is_atomic(true), |
duke@435 | 431 | _enqueuing_is_done(false), |
duke@435 | 432 | _discovery_is_mt(false), |
ysr@777 | 433 | _discovered_list_needs_barrier(false), |
ysr@777 | 434 | _bs(NULL), |
duke@435 | 435 | _is_alive_non_header(NULL), |
duke@435 | 436 | _num_q(0), |
jmasa@2188 | 437 | _max_num_q(0), |
duke@435 | 438 | _processing_is_mt(false), |
duke@435 | 439 | _next_id(0) |
ysr@2651 | 440 | { } |
duke@435 | 441 | |
ysr@2651 | 442 | // Default parameters give you a vanilla reference processor. |
ysr@2651 | 443 | ReferenceProcessor(MemRegion span, |
jmasa@3357 | 444 | bool mt_processing = false, uint mt_processing_degree = 1, |
jmasa@3357 | 445 | bool mt_discovery = false, uint mt_discovery_degree = 1, |
ysr@2651 | 446 | bool atomic_discovery = true, |
ysr@2651 | 447 | BoolObjectClosure* is_alive_non_header = NULL, |
ysr@777 | 448 | bool discovered_list_needs_barrier = false); |
duke@435 | 449 | |
duke@435 | 450 | // RefDiscoveryPolicy values |
johnc@1679 | 451 | enum DiscoveryPolicy { |
duke@435 | 452 | ReferenceBasedDiscovery = 0, |
johnc@1679 | 453 | ReferentBasedDiscovery = 1, |
johnc@1679 | 454 | DiscoveryPolicyMin = ReferenceBasedDiscovery, |
johnc@1679 | 455 | DiscoveryPolicyMax = ReferentBasedDiscovery |
duke@435 | 456 | }; |
duke@435 | 457 | |
duke@435 | 458 | static void init_statics(); |
duke@435 | 459 | |
duke@435 | 460 | public: |
duke@435 | 461 | // get and set "is_alive_non_header" field |
duke@435 | 462 | BoolObjectClosure* is_alive_non_header() { |
duke@435 | 463 | return _is_alive_non_header; |
duke@435 | 464 | } |
duke@435 | 465 | void set_is_alive_non_header(BoolObjectClosure* is_alive_non_header) { |
duke@435 | 466 | _is_alive_non_header = is_alive_non_header; |
duke@435 | 467 | } |
duke@435 | 468 | |
duke@435 | 469 | // get and set span |
duke@435 | 470 | MemRegion span() { return _span; } |
duke@435 | 471 | void set_span(MemRegion span) { _span = span; } |
duke@435 | 472 | |
duke@435 | 473 | // start and stop weak ref discovery |
johnc@3188 | 474 | void enable_discovery(bool verify_disabled, bool check_no_refs); |
duke@435 | 475 | void disable_discovery() { _discovering_refs = false; } |
duke@435 | 476 | bool discovery_enabled() { return _discovering_refs; } |
duke@435 | 477 | |
duke@435 | 478 | // whether discovery is atomic wrt other collectors |
duke@435 | 479 | bool discovery_is_atomic() const { return _discovery_is_atomic; } |
duke@435 | 480 | void set_atomic_discovery(bool atomic) { _discovery_is_atomic = atomic; } |
duke@435 | 481 | |
ysr@3117 | 482 | // whether the JDK in which we are embedded is a pre-4965777 JDK, |
ysr@3117 | 483 | // and thus whether or not it uses the discovered field to chain |
ysr@3117 | 484 | // the entries in the pending list. |
ysr@3117 | 485 | static bool pending_list_uses_discovered_field() { |
ysr@3117 | 486 | return _pending_list_uses_discovered_field; |
ysr@3117 | 487 | } |
ysr@3117 | 488 | |
duke@435 | 489 | // whether discovery is done by multiple threads same-old-timeously |
duke@435 | 490 | bool discovery_is_mt() const { return _discovery_is_mt; } |
duke@435 | 491 | void set_mt_discovery(bool mt) { _discovery_is_mt = mt; } |
duke@435 | 492 | |
duke@435 | 493 | // Whether we are in a phase when _processing_ is MT. |
duke@435 | 494 | bool processing_is_mt() const { return _processing_is_mt; } |
duke@435 | 495 | void set_mt_processing(bool mt) { _processing_is_mt = mt; } |
duke@435 | 496 | |
duke@435 | 497 | // whether all enqueuing of weak references is complete |
duke@435 | 498 | bool enqueuing_is_done() { return _enqueuing_is_done; } |
duke@435 | 499 | void set_enqueuing_is_done(bool v) { _enqueuing_is_done = v; } |
duke@435 | 500 | |
duke@435 | 501 | // iterate over oops |
duke@435 | 502 | void weak_oops_do(OopClosure* f); // weak roots |
duke@435 | 503 | |
jmasa@2188 | 504 | // Balance each of the discovered lists. |
jmasa@2188 | 505 | void balance_all_queues(); |
coleenp@4037 | 506 | void verify_list(DiscoveredList& ref_list); |
jmasa@2188 | 507 | |
duke@435 | 508 | // Discover a Reference object, using appropriate discovery criteria |
duke@435 | 509 | bool discover_reference(oop obj, ReferenceType rt); |
duke@435 | 510 | |
duke@435 | 511 | // Process references found during GC (called by the garbage collector) |
sla@5237 | 512 | ReferenceProcessorStats |
sla@5237 | 513 | process_discovered_references(BoolObjectClosure* is_alive, |
sla@5237 | 514 | OopClosure* keep_alive, |
sla@5237 | 515 | VoidClosure* complete_gc, |
sla@5237 | 516 | AbstractRefProcTaskExecutor* task_executor, |
sla@5237 | 517 | GCTimer *gc_timer); |
duke@435 | 518 | |
duke@435 | 519 | // Enqueue references at end of GC (called by the garbage collector) |
duke@435 | 520 | bool enqueue_discovered_references(AbstractRefProcTaskExecutor* task_executor = NULL); |
duke@435 | 521 | |
ysr@777 | 522 | // If a discovery is in process that is being superceded, abandon it: all |
ysr@777 | 523 | // the discovered lists will be empty, and all the objects on them will |
ysr@777 | 524 | // have NULL discovered fields. Must be called only at a safepoint. |
ysr@777 | 525 | void abandon_partial_discovery(); |
ysr@777 | 526 | |
duke@435 | 527 | // debugging |
duke@435 | 528 | void verify_no_references_recorded() PRODUCT_RETURN; |
ysr@2337 | 529 | void verify_referent(oop obj) PRODUCT_RETURN; |
duke@435 | 530 | |
duke@435 | 531 | // clear the discovered lists (unlinking each entry). |
duke@435 | 532 | void clear_discovered_references() PRODUCT_RETURN; |
duke@435 | 533 | }; |
duke@435 | 534 | |
duke@435 | 535 | // A utility class to disable reference discovery in |
duke@435 | 536 | // the scope which contains it, for given ReferenceProcessor. |
duke@435 | 537 | class NoRefDiscovery: StackObj { |
duke@435 | 538 | private: |
duke@435 | 539 | ReferenceProcessor* _rp; |
duke@435 | 540 | bool _was_discovering_refs; |
duke@435 | 541 | public: |
duke@435 | 542 | NoRefDiscovery(ReferenceProcessor* rp) : _rp(rp) { |
twisti@2144 | 543 | _was_discovering_refs = _rp->discovery_enabled(); |
twisti@2144 | 544 | if (_was_discovering_refs) { |
duke@435 | 545 | _rp->disable_discovery(); |
duke@435 | 546 | } |
duke@435 | 547 | } |
duke@435 | 548 | |
duke@435 | 549 | ~NoRefDiscovery() { |
duke@435 | 550 | if (_was_discovering_refs) { |
johnc@3175 | 551 | _rp->enable_discovery(true /*verify_disabled*/, false /*check_no_refs*/); |
duke@435 | 552 | } |
duke@435 | 553 | } |
duke@435 | 554 | }; |
duke@435 | 555 | |
duke@435 | 556 | |
duke@435 | 557 | // A utility class to temporarily mutate the span of the |
duke@435 | 558 | // given ReferenceProcessor in the scope that contains it. |
duke@435 | 559 | class ReferenceProcessorSpanMutator: StackObj { |
duke@435 | 560 | private: |
duke@435 | 561 | ReferenceProcessor* _rp; |
duke@435 | 562 | MemRegion _saved_span; |
duke@435 | 563 | |
duke@435 | 564 | public: |
duke@435 | 565 | ReferenceProcessorSpanMutator(ReferenceProcessor* rp, |
duke@435 | 566 | MemRegion span): |
duke@435 | 567 | _rp(rp) { |
duke@435 | 568 | _saved_span = _rp->span(); |
duke@435 | 569 | _rp->set_span(span); |
duke@435 | 570 | } |
duke@435 | 571 | |
duke@435 | 572 | ~ReferenceProcessorSpanMutator() { |
duke@435 | 573 | _rp->set_span(_saved_span); |
duke@435 | 574 | } |
duke@435 | 575 | }; |
duke@435 | 576 | |
duke@435 | 577 | // A utility class to temporarily change the MT'ness of |
duke@435 | 578 | // reference discovery for the given ReferenceProcessor |
duke@435 | 579 | // in the scope that contains it. |
ysr@2651 | 580 | class ReferenceProcessorMTDiscoveryMutator: StackObj { |
duke@435 | 581 | private: |
duke@435 | 582 | ReferenceProcessor* _rp; |
duke@435 | 583 | bool _saved_mt; |
duke@435 | 584 | |
duke@435 | 585 | public: |
ysr@2651 | 586 | ReferenceProcessorMTDiscoveryMutator(ReferenceProcessor* rp, |
ysr@2651 | 587 | bool mt): |
duke@435 | 588 | _rp(rp) { |
duke@435 | 589 | _saved_mt = _rp->discovery_is_mt(); |
duke@435 | 590 | _rp->set_mt_discovery(mt); |
duke@435 | 591 | } |
duke@435 | 592 | |
ysr@2651 | 593 | ~ReferenceProcessorMTDiscoveryMutator() { |
duke@435 | 594 | _rp->set_mt_discovery(_saved_mt); |
duke@435 | 595 | } |
duke@435 | 596 | }; |
duke@435 | 597 | |
duke@435 | 598 | |
duke@435 | 599 | // A utility class to temporarily change the disposition |
duke@435 | 600 | // of the "is_alive_non_header" closure field of the |
duke@435 | 601 | // given ReferenceProcessor in the scope that contains it. |
duke@435 | 602 | class ReferenceProcessorIsAliveMutator: StackObj { |
duke@435 | 603 | private: |
duke@435 | 604 | ReferenceProcessor* _rp; |
duke@435 | 605 | BoolObjectClosure* _saved_cl; |
duke@435 | 606 | |
duke@435 | 607 | public: |
duke@435 | 608 | ReferenceProcessorIsAliveMutator(ReferenceProcessor* rp, |
duke@435 | 609 | BoolObjectClosure* cl): |
duke@435 | 610 | _rp(rp) { |
duke@435 | 611 | _saved_cl = _rp->is_alive_non_header(); |
duke@435 | 612 | _rp->set_is_alive_non_header(cl); |
duke@435 | 613 | } |
duke@435 | 614 | |
duke@435 | 615 | ~ReferenceProcessorIsAliveMutator() { |
duke@435 | 616 | _rp->set_is_alive_non_header(_saved_cl); |
duke@435 | 617 | } |
duke@435 | 618 | }; |
duke@435 | 619 | |
duke@435 | 620 | // A utility class to temporarily change the disposition |
duke@435 | 621 | // of the "discovery_is_atomic" field of the |
duke@435 | 622 | // given ReferenceProcessor in the scope that contains it. |
duke@435 | 623 | class ReferenceProcessorAtomicMutator: StackObj { |
duke@435 | 624 | private: |
duke@435 | 625 | ReferenceProcessor* _rp; |
duke@435 | 626 | bool _saved_atomic_discovery; |
duke@435 | 627 | |
duke@435 | 628 | public: |
duke@435 | 629 | ReferenceProcessorAtomicMutator(ReferenceProcessor* rp, |
duke@435 | 630 | bool atomic): |
duke@435 | 631 | _rp(rp) { |
duke@435 | 632 | _saved_atomic_discovery = _rp->discovery_is_atomic(); |
duke@435 | 633 | _rp->set_atomic_discovery(atomic); |
duke@435 | 634 | } |
duke@435 | 635 | |
duke@435 | 636 | ~ReferenceProcessorAtomicMutator() { |
duke@435 | 637 | _rp->set_atomic_discovery(_saved_atomic_discovery); |
duke@435 | 638 | } |
duke@435 | 639 | }; |
duke@435 | 640 | |
duke@435 | 641 | |
duke@435 | 642 | // A utility class to temporarily change the MT processing |
duke@435 | 643 | // disposition of the given ReferenceProcessor instance |
duke@435 | 644 | // in the scope that contains it. |
duke@435 | 645 | class ReferenceProcessorMTProcMutator: StackObj { |
duke@435 | 646 | private: |
duke@435 | 647 | ReferenceProcessor* _rp; |
duke@435 | 648 | bool _saved_mt; |
duke@435 | 649 | |
duke@435 | 650 | public: |
duke@435 | 651 | ReferenceProcessorMTProcMutator(ReferenceProcessor* rp, |
duke@435 | 652 | bool mt): |
duke@435 | 653 | _rp(rp) { |
duke@435 | 654 | _saved_mt = _rp->processing_is_mt(); |
duke@435 | 655 | _rp->set_mt_processing(mt); |
duke@435 | 656 | } |
duke@435 | 657 | |
duke@435 | 658 | ~ReferenceProcessorMTProcMutator() { |
duke@435 | 659 | _rp->set_mt_processing(_saved_mt); |
duke@435 | 660 | } |
duke@435 | 661 | }; |
duke@435 | 662 | |
duke@435 | 663 | |
duke@435 | 664 | // This class is an interface used to implement task execution for the |
duke@435 | 665 | // reference processing. |
duke@435 | 666 | class AbstractRefProcTaskExecutor { |
duke@435 | 667 | public: |
duke@435 | 668 | |
duke@435 | 669 | // Abstract tasks to execute. |
duke@435 | 670 | class ProcessTask; |
duke@435 | 671 | class EnqueueTask; |
duke@435 | 672 | |
duke@435 | 673 | // Executes a task using worker threads. |
duke@435 | 674 | virtual void execute(ProcessTask& task) = 0; |
duke@435 | 675 | virtual void execute(EnqueueTask& task) = 0; |
duke@435 | 676 | |
duke@435 | 677 | // Switch to single threaded mode. |
duke@435 | 678 | virtual void set_single_threaded_mode() { }; |
duke@435 | 679 | }; |
duke@435 | 680 | |
duke@435 | 681 | // Abstract reference processing task to execute. |
duke@435 | 682 | class AbstractRefProcTaskExecutor::ProcessTask { |
duke@435 | 683 | protected: |
duke@435 | 684 | ProcessTask(ReferenceProcessor& ref_processor, |
duke@435 | 685 | DiscoveredList refs_lists[], |
duke@435 | 686 | bool marks_oops_alive) |
duke@435 | 687 | : _ref_processor(ref_processor), |
duke@435 | 688 | _refs_lists(refs_lists), |
duke@435 | 689 | _marks_oops_alive(marks_oops_alive) |
duke@435 | 690 | { } |
duke@435 | 691 | |
duke@435 | 692 | public: |
duke@435 | 693 | virtual void work(unsigned int work_id, BoolObjectClosure& is_alive, |
duke@435 | 694 | OopClosure& keep_alive, |
duke@435 | 695 | VoidClosure& complete_gc) = 0; |
duke@435 | 696 | |
duke@435 | 697 | // Returns true if a task marks some oops as alive. |
duke@435 | 698 | bool marks_oops_alive() const |
duke@435 | 699 | { return _marks_oops_alive; } |
duke@435 | 700 | |
duke@435 | 701 | protected: |
duke@435 | 702 | ReferenceProcessor& _ref_processor; |
duke@435 | 703 | DiscoveredList* _refs_lists; |
duke@435 | 704 | const bool _marks_oops_alive; |
duke@435 | 705 | }; |
duke@435 | 706 | |
duke@435 | 707 | // Abstract reference processing task to execute. |
duke@435 | 708 | class AbstractRefProcTaskExecutor::EnqueueTask { |
duke@435 | 709 | protected: |
duke@435 | 710 | EnqueueTask(ReferenceProcessor& ref_processor, |
duke@435 | 711 | DiscoveredList refs_lists[], |
coleenp@548 | 712 | HeapWord* pending_list_addr, |
duke@435 | 713 | int n_queues) |
duke@435 | 714 | : _ref_processor(ref_processor), |
duke@435 | 715 | _refs_lists(refs_lists), |
duke@435 | 716 | _pending_list_addr(pending_list_addr), |
duke@435 | 717 | _n_queues(n_queues) |
duke@435 | 718 | { } |
duke@435 | 719 | |
duke@435 | 720 | public: |
duke@435 | 721 | virtual void work(unsigned int work_id) = 0; |
duke@435 | 722 | |
duke@435 | 723 | protected: |
duke@435 | 724 | ReferenceProcessor& _ref_processor; |
duke@435 | 725 | DiscoveredList* _refs_lists; |
coleenp@548 | 726 | HeapWord* _pending_list_addr; |
duke@435 | 727 | int _n_queues; |
duke@435 | 728 | }; |
stefank@2314 | 729 | |
stefank@2314 | 730 | #endif // SHARE_VM_MEMORY_REFERENCEPROCESSOR_HPP |