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Elliott Hughes5f791332011-09-15 17:45:30 -07001/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
Brian Carlstromfc0e3212013-07-17 14:40:12 -070017#ifndef ART_RUNTIME_MONITOR_H_
18#define ART_RUNTIME_MONITOR_H_
Elliott Hughes5f791332011-09-15 17:45:30 -070019
20#include <pthread.h>
21#include <stdint.h>
Brian Carlstromc57ad202015-03-03 21:21:29 -080022#include <stdlib.h>
Elliott Hughes5f791332011-09-15 17:45:30 -070023
Elliott Hughes8e4aac52011-09-26 17:03:36 -070024#include <iosfwd>
Elliott Hughesc33a32b2011-10-11 18:18:07 -070025#include <list>
Elliott Hughesf327e072013-01-09 16:01:26 -080026#include <vector>
Elliott Hughes8e4aac52011-09-26 17:03:36 -070027
Ian Rogersef7d42f2014-01-06 12:55:46 -080028#include "atomic.h"
Mathieu Chartierbad02672014-08-25 13:08:22 -070029#include "base/allocator.h"
Elliott Hughes76b61672012-12-12 17:47:30 -080030#include "base/mutex.h"
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070031#include "gc_root.h"
Hiroshi Yamauchie15ea082015-02-09 17:11:42 -080032#include "lock_word.h"
Mathieu Chartier83c8ee02014-01-28 14:50:23 -080033#include "object_callbacks.h"
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -070034#include "read_barrier_option.h"
Ian Rogers2dd0e2c2013-01-24 12:42:14 -080035#include "thread_state.h"
Elliott Hughes5f791332011-09-15 17:45:30 -070036
37namespace art {
38
Mathieu Chartiere401d142015-04-22 13:56:20 -070039class ArtMethod;
Ian Rogersb0fa5dc2014-04-28 16:47:08 -070040class LockWord;
Mathieu Chartiereb8167a2014-05-07 15:43:14 -070041template<class T> class Handle;
Ian Rogersb0fa5dc2014-04-28 16:47:08 -070042class StackVisitor;
Mathieu Chartiere401d142015-04-22 13:56:20 -070043class Thread;
Ian Rogersb0fa5dc2014-04-28 16:47:08 -070044typedef uint32_t MonitorId;
Mathieu Chartierc645f1d2014-03-06 18:11:53 -080045
Ian Rogers2dd0e2c2013-01-24 12:42:14 -080046namespace mirror {
Brian Carlstromea46f952013-07-30 01:26:50 -070047 class Object;
Ian Rogers2dd0e2c2013-01-24 12:42:14 -080048} // namespace mirror
Ian Rogersef7d42f2014-01-06 12:55:46 -080049
Elliott Hughes5f791332011-09-15 17:45:30 -070050class Monitor {
51 public:
Ian Rogersd9c4fc92013-10-01 19:45:43 -070052 // The default number of spins that are done before thread suspension is used to forcibly inflate
53 // a lock word. See Runtime::max_spins_before_thin_lock_inflation_.
54 constexpr static size_t kDefaultMaxSpinsBeforeThinLockInflation = 50;
55
Elliott Hughes5f791332011-09-15 17:45:30 -070056 ~Monitor();
57
Calin Juravleb2771b42016-04-07 17:09:25 +010058 static void Init(uint32_t lock_profiling_threshold);
Elliott Hughes32d6e1e2011-10-11 14:47:44 -070059
Ian Rogersd9c4fc92013-10-01 19:45:43 -070060 // Return the thread id of the lock owner or 0 when there is no owner.
61 static uint32_t GetLockOwnerThreadId(mirror::Object* obj)
62 NO_THREAD_SAFETY_ANALYSIS; // TODO: Reading lock owner without holding lock is racy.
Elliott Hughes5f791332011-09-15 17:45:30 -070063
Mathieu Chartier90443472015-07-16 20:32:27 -070064 // NO_THREAD_SAFETY_ANALYSIS for mon->Lock.
Mathieu Chartier4b0ef1c2016-07-29 16:26:01 -070065 static mirror::Object* MonitorEnter(Thread* thread, mirror::Object* obj, bool trylock)
Ian Rogers719d1a32014-03-06 12:13:39 -080066 EXCLUSIVE_LOCK_FUNCTION(obj)
Mathieu Chartier2d096c92015-10-12 16:18:20 -070067 NO_THREAD_SAFETY_ANALYSIS
68 REQUIRES(!Roles::uninterruptible_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070069 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -070070
Mathieu Chartier90443472015-07-16 20:32:27 -070071 // NO_THREAD_SAFETY_ANALYSIS for mon->Unlock.
72 static bool MonitorExit(Thread* thread, mirror::Object* obj)
Mathieu Chartier2d096c92015-10-12 16:18:20 -070073 NO_THREAD_SAFETY_ANALYSIS
74 REQUIRES(!Roles::uninterruptible_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070075 REQUIRES_SHARED(Locks::mutator_lock_)
Mathieu Chartier2d096c92015-10-12 16:18:20 -070076 UNLOCK_FUNCTION(obj);
Mathieu Chartier90443472015-07-16 20:32:27 -070077
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070078 static void Notify(Thread* self, mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_) {
Ian Rogers13c479e2013-10-11 07:59:01 -070079 DoNotify(self, obj, false);
Ian Rogersd9c4fc92013-10-01 19:45:43 -070080 }
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070081 static void NotifyAll(Thread* self, mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_) {
Ian Rogers13c479e2013-10-11 07:59:01 -070082 DoNotify(self, obj, true);
Ian Rogersd9c4fc92013-10-01 19:45:43 -070083 }
Ian Rogers0ef3bd22014-08-15 13:39:34 -070084
85 // Object.wait(). Also called for class init.
Mathieu Chartier90443472015-07-16 20:32:27 -070086 // NO_THREAD_SAFETY_ANALYSIS for mon->Wait.
Ian Rogers2dd0e2c2013-01-24 12:42:14 -080087 static void Wait(Thread* self, mirror::Object* obj, int64_t ms, int32_t ns,
88 bool interruptShouldThrow, ThreadState why)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070089 REQUIRES_SHARED(Locks::mutator_lock_) NO_THREAD_SAFETY_ANALYSIS;
Elliott Hughes5f791332011-09-15 17:45:30 -070090
Ian Rogers00f7d0e2012-07-19 15:28:27 -070091 static void DescribeWait(std::ostream& os, const Thread* thread)
Mathieu Chartier90443472015-07-16 20:32:27 -070092 REQUIRES(!Locks::thread_suspend_count_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070093 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughes4993bbc2013-01-10 15:41:25 -080094
Elliott Hughesf9501702013-01-11 11:22:27 -080095 // Used to implement JDWP's ThreadReference.CurrentContendedMonitor.
Ian Rogersd9c4fc92013-10-01 19:45:43 -070096 static mirror::Object* GetContendedMonitor(Thread* thread)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -070097 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughesf9501702013-01-11 11:22:27 -080098
Elliott Hughes4993bbc2013-01-10 15:41:25 -080099 // Calls 'callback' once for each lock held in the single stack frame represented by
100 // the current state of 'stack_visitor'.
Andreas Gampe956a5222014-08-16 13:41:10 -0700101 // The abort_on_failure flag allows to not die when the state of the runtime is unorderly. This
102 // is necessary when we have already aborted but want to dump the stack as much as we can.
Ian Rogers2dd0e2c2013-01-24 12:42:14 -0800103 static void VisitLocks(StackVisitor* stack_visitor, void (*callback)(mirror::Object*, void*),
Andreas Gampe956a5222014-08-16 13:41:10 -0700104 void* callback_context, bool abort_on_failure = true)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700105 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughes8e4aac52011-09-26 17:03:36 -0700106
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700107 static bool IsValidLockWord(LockWord lock_word);
Ian Rogers7dfb28c2013-08-22 08:18:36 -0700108
Hiroshi Yamauchi4cba0d92014-05-21 21:10:23 -0700109 template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700110 mirror::Object* GetObject() REQUIRES_SHARED(Locks::mutator_lock_) {
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -0700111 return obj_.Read<kReadBarrierOption>();
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700112 }
113
Mathieu Chartier6aa3df92013-09-17 15:17:28 -0700114 void SetObject(mirror::Object* object);
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700115
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700116 Thread* GetOwner() const NO_THREAD_SAFETY_ANALYSIS {
117 return owner_;
118 }
119
Mathieu Chartier4e6a31e2013-10-31 10:35:05 -0700120 int32_t GetHashCode();
Mathieu Chartierad2541a2013-10-25 10:05:23 -0700121
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700122 bool IsLocked() REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!monitor_lock_);
Mathieu Chartierad2541a2013-10-25 10:05:23 -0700123
Mathieu Chartier4e6a31e2013-10-31 10:35:05 -0700124 bool HasHashCode() const {
Ian Rogers3e5cf302014-05-20 16:40:37 -0700125 return hash_code_.LoadRelaxed() != 0;
Mathieu Chartier4e6a31e2013-10-31 10:35:05 -0700126 }
127
Ian Rogersef7d42f2014-01-06 12:55:46 -0800128 MonitorId GetMonitorId() const {
129 return monitor_id_;
130 }
131
Ian Rogers43c69cc2014-08-15 11:09:28 -0700132 // Inflate the lock on obj. May fail to inflate for spurious reasons, always re-check.
Mathieu Chartier0cd81352014-05-22 16:48:55 -0700133 static void InflateThinLocked(Thread* self, Handle<mirror::Object> obj, LockWord lock_word,
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700134 uint32_t hash_code) REQUIRES_SHARED(Locks::mutator_lock_);
Mathieu Chartierad2541a2013-10-25 10:05:23 -0700135
Mathieu Chartier90443472015-07-16 20:32:27 -0700136 // Not exclusive because ImageWriter calls this during a Heap::VisitObjects() that
137 // does not allow a thread suspension in the middle. TODO: maybe make this exclusive.
138 // NO_THREAD_SAFETY_ANALYSIS for monitor->monitor_lock_.
Mathieu Chartier590fee92013-09-13 13:46:47 -0700139 static bool Deflate(Thread* self, mirror::Object* obj)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700140 REQUIRES_SHARED(Locks::mutator_lock_) NO_THREAD_SAFETY_ANALYSIS;
Mathieu Chartier590fee92013-09-13 13:46:47 -0700141
Hiroshi Yamauchie15ea082015-02-09 17:11:42 -0800142#ifndef __LP64__
143 void* operator new(size_t size) {
144 // Align Monitor* as per the monitor ID field size in the lock word.
Brian Carlstromc57ad202015-03-03 21:21:29 -0800145 void* result;
146 int error = posix_memalign(&result, LockWord::kMonitorIdAlignment, size);
147 CHECK_EQ(error, 0) << strerror(error);
148 return result;
Hiroshi Yamauchie15ea082015-02-09 17:11:42 -0800149 }
Christopher Ferris8a354052015-04-24 17:23:53 -0700150
151 void operator delete(void* ptr) {
152 free(ptr);
153 }
Hiroshi Yamauchie15ea082015-02-09 17:11:42 -0800154#endif
155
Elliott Hughes5f791332011-09-15 17:45:30 -0700156 private:
Roland Levillain3887c462015-08-12 18:15:42 +0100157 Monitor(Thread* self, Thread* owner, mirror::Object* obj, int32_t hash_code)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700158 REQUIRES_SHARED(Locks::mutator_lock_);
Roland Levillain3887c462015-08-12 18:15:42 +0100159 Monitor(Thread* self, Thread* owner, mirror::Object* obj, int32_t hash_code, MonitorId id)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700160 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700161
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700162 // Install the monitor into its object, may fail if another thread installs a different monitor
163 // first.
164 bool Install(Thread* self)
Mathieu Chartier90443472015-07-16 20:32:27 -0700165 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700166 REQUIRES_SHARED(Locks::mutator_lock_);
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700167
Ian Rogers0ef3bd22014-08-15 13:39:34 -0700168 // Links a thread into a monitor's wait set. The monitor lock must be held by the caller of this
169 // routine.
Mathieu Chartier90443472015-07-16 20:32:27 -0700170 void AppendToWaitSet(Thread* thread) REQUIRES(monitor_lock_);
Ian Rogers0ef3bd22014-08-15 13:39:34 -0700171
172 // Unlinks a thread from a monitor's wait set. The monitor lock must be held by the caller of
173 // this routine.
Mathieu Chartier90443472015-07-16 20:32:27 -0700174 void RemoveFromWaitSet(Thread* thread) REQUIRES(monitor_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700175
Ian Rogers0ef3bd22014-08-15 13:39:34 -0700176 // Changes the shape of a monitor from thin to fat, preserving the internal lock state. The
177 // calling thread must own the lock or the owner must be suspended. There's a race with other
178 // threads inflating the lock, installing hash codes and spurious failures. The caller should
179 // re-read the lock word following the call.
Mathieu Chartierad2541a2013-10-25 10:05:23 -0700180 static void Inflate(Thread* self, Thread* owner, mirror::Object* obj, int32_t hash_code)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700181 REQUIRES_SHARED(Locks::mutator_lock_)
Mathieu Chartier90443472015-07-16 20:32:27 -0700182 NO_THREAD_SAFETY_ANALYSIS; // For m->Install(self)
Elliott Hughes5f791332011-09-15 17:45:30 -0700183
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700184 void LogContentionEvent(Thread* self, uint32_t wait_ms, uint32_t sample_percent,
Brian Carlstromeaa46092015-10-07 21:29:28 -0700185 const char* owner_filename, int32_t owner_line_number)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700186 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughesfc861622011-10-17 17:57:47 -0700187
Mathieu Chartier61b3cd42016-04-18 11:43:29 -0700188 static void FailedUnlock(mirror::Object* obj,
189 uint32_t expected_owner_thread_id,
190 uint32_t found_owner_thread_id,
Brian Carlstromc57ad202015-03-03 21:21:29 -0800191 Monitor* mon)
Mathieu Chartier61b3cd42016-04-18 11:43:29 -0700192 REQUIRES(!Locks::thread_list_lock_,
193 !monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700194 REQUIRES_SHARED(Locks::mutator_lock_);
Ian Rogers6d0b13e2012-02-07 09:25:29 -0800195
Mathieu Chartier4b0ef1c2016-07-29 16:26:01 -0700196 // Try to lock without blocking, returns true if we acquired the lock.
197 bool TryLock(Thread* self)
198 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700199 REQUIRES_SHARED(Locks::mutator_lock_);
Mathieu Chartier4b0ef1c2016-07-29 16:26:01 -0700200 // Variant for already holding the monitor lock.
201 bool TryLockLocked(Thread* self)
202 REQUIRES(monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700203 REQUIRES_SHARED(Locks::mutator_lock_);
Mathieu Chartier4b0ef1c2016-07-29 16:26:01 -0700204
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700205 void Lock(Thread* self)
Mathieu Chartier90443472015-07-16 20:32:27 -0700206 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700207 REQUIRES_SHARED(Locks::mutator_lock_);
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700208 bool Unlock(Thread* thread)
Mathieu Chartier90443472015-07-16 20:32:27 -0700209 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700210 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700211
Ian Rogers13c479e2013-10-11 07:59:01 -0700212 static void DoNotify(Thread* self, mirror::Object* obj, bool notify_all)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700213 REQUIRES_SHARED(Locks::mutator_lock_) NO_THREAD_SAFETY_ANALYSIS; // For mon->Notify.
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700214
215 void Notify(Thread* self)
Mathieu Chartier90443472015-07-16 20:32:27 -0700216 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700217 REQUIRES_SHARED(Locks::mutator_lock_);
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700218
219 void NotifyAll(Thread* self)
Mathieu Chartier90443472015-07-16 20:32:27 -0700220 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700221 REQUIRES_SHARED(Locks::mutator_lock_);
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700222
Mathieu Chartier0ffdc9c2016-04-19 13:46:03 -0700223 static std::string PrettyContentionInfo(const std::string& owner_name,
224 pid_t owner_tid,
Mathieu Chartier74b3c8f2016-04-15 19:11:45 -0700225 ArtMethod* owners_method,
226 uint32_t owners_dex_pc,
227 size_t num_waiters)
Mathieu Chartier0ffdc9c2016-04-19 13:46:03 -0700228 REQUIRES(!Locks::thread_list_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700229 REQUIRES_SHARED(Locks::mutator_lock_);
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700230
Ian Rogers0ef3bd22014-08-15 13:39:34 -0700231 // Wait on a monitor until timeout, interrupt, or notification. Used for Object.wait() and
232 // (somewhat indirectly) Thread.sleep() and Thread.join().
233 //
234 // If another thread calls Thread.interrupt(), we throw InterruptedException and return
235 // immediately if one of the following are true:
236 // - blocked in wait(), wait(long), or wait(long, int) methods of Object
237 // - blocked in join(), join(long), or join(long, int) methods of Thread
238 // - blocked in sleep(long), or sleep(long, int) methods of Thread
239 // Otherwise, we set the "interrupted" flag.
240 //
241 // Checks to make sure that "ns" is in the range 0-999999 (i.e. fractions of a millisecond) and
242 // throws the appropriate exception if it isn't.
243 //
244 // The spec allows "spurious wakeups", and recommends that all code using Object.wait() do so in
245 // a loop. This appears to derive from concerns about pthread_cond_wait() on multiprocessor
246 // systems. Some commentary on the web casts doubt on whether these can/should occur.
247 //
248 // Since we're allowed to wake up "early", we clamp extremely long durations to return at the end
249 // of the 32-bit time epoch.
Elliott Hughes4cd121e2013-01-07 17:35:41 -0800250 void Wait(Thread* self, int64_t msec, int32_t nsec, bool interruptShouldThrow, ThreadState why)
Mathieu Chartier90443472015-07-16 20:32:27 -0700251 REQUIRES(!monitor_lock_)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700252 REQUIRES_SHARED(Locks::mutator_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700253
jeffhao33dc7712011-11-09 17:54:24 -0800254 // Translates the provided method and pc into its declaring class' source file and line number.
Mathieu Chartier74b3c8f2016-04-15 19:11:45 -0700255 static void TranslateLocation(ArtMethod* method, uint32_t pc,
256 const char** source_file,
257 int32_t* line_number)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700258 REQUIRES_SHARED(Locks::mutator_lock_);
jeffhao33dc7712011-11-09 17:54:24 -0800259
Mathieu Chartier90443472015-07-16 20:32:27 -0700260 uint32_t GetOwnerThreadId() REQUIRES(!monitor_lock_);
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700261
Andreas Gampec7ed09b2016-04-25 20:08:55 -0700262 // Support for systrace output of monitor operations.
263 ALWAYS_INLINE static void AtraceMonitorLock(Thread* self,
264 mirror::Object* obj,
265 bool is_wait)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700266 REQUIRES_SHARED(Locks::mutator_lock_);
Andreas Gampec7ed09b2016-04-25 20:08:55 -0700267 static void AtraceMonitorLockImpl(Thread* self,
268 mirror::Object* obj,
269 bool is_wait)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700270 REQUIRES_SHARED(Locks::mutator_lock_);
Andreas Gampec7ed09b2016-04-25 20:08:55 -0700271 ALWAYS_INLINE static void AtraceMonitorUnlock();
272
Elliott Hughesfc861622011-10-17 17:57:47 -0700273 static uint32_t lock_profiling_threshold_;
Elliott Hughes32d6e1e2011-10-11 14:47:44 -0700274
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700275 Mutex monitor_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
Ian Rogers719d1a32014-03-06 12:13:39 -0800276
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700277 ConditionVariable monitor_contenders_ GUARDED_BY(monitor_lock_);
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700278
Mathieu Chartier46bc7782013-11-12 17:03:02 -0800279 // Number of people waiting on the condition.
280 size_t num_waiters_ GUARDED_BY(monitor_lock_);
281
Brian Carlstrom4514d3c2011-10-21 17:01:31 -0700282 // Which thread currently owns the lock?
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700283 Thread* volatile owner_ GUARDED_BY(monitor_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700284
Brian Carlstrom4514d3c2011-10-21 17:01:31 -0700285 // Owner's recursive lock depth.
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700286 int lock_count_ GUARDED_BY(monitor_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700287
Hiroshi Yamauchi4cba0d92014-05-21 21:10:23 -0700288 // What object are we part of. This is a weak root. Do not access
289 // this directly, use GetObject() to read it so it will be guarded
290 // by a read barrier.
Hiroshi Yamauchi94f7b492014-07-22 18:08:23 -0700291 GcRoot<mirror::Object> obj_;
Elliott Hughes5f791332011-09-15 17:45:30 -0700292
Brian Carlstrom4514d3c2011-10-21 17:01:31 -0700293 // Threads currently waiting on this monitor.
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700294 Thread* wait_set_ GUARDED_BY(monitor_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700295
Mathieu Chartier4e6a31e2013-10-31 10:35:05 -0700296 // Stored object hash code, generated lazily by GetHashCode.
297 AtomicInteger hash_code_;
Mathieu Chartierad2541a2013-10-25 10:05:23 -0700298
Ian Rogers0399dde2012-06-06 17:09:28 -0700299 // Method and dex pc where the lock owner acquired the lock, used when lock
jeffhao33dc7712011-11-09 17:54:24 -0800300 // sampling is enabled. locking_method_ may be null if the lock is currently
301 // unlocked, or if the lock is acquired by the system when the stack is empty.
Mathieu Chartiere401d142015-04-22 13:56:20 -0700302 ArtMethod* locking_method_ GUARDED_BY(monitor_lock_);
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700303 uint32_t locking_dex_pc_ GUARDED_BY(monitor_lock_);
Elliott Hughes5f791332011-09-15 17:45:30 -0700304
Ian Rogersef7d42f2014-01-06 12:55:46 -0800305 // The denser encoded version of this monitor as stored in the lock word.
306 MonitorId monitor_id_;
307
Andreas Gampe74240812014-04-17 10:35:09 -0700308#ifdef __LP64__
309 // Free list for monitor pool.
310 Monitor* next_free_ GUARDED_BY(Locks::allocated_monitor_ids_lock_);
311#endif
312
Elliott Hughesf327e072013-01-09 16:01:26 -0800313 friend class MonitorInfo;
Brian Carlstrom4514d3c2011-10-21 17:01:31 -0700314 friend class MonitorList;
Andreas Gampe74240812014-04-17 10:35:09 -0700315 friend class MonitorPool;
Ian Rogers2dd0e2c2013-01-24 12:42:14 -0800316 friend class mirror::Object;
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700317 DISALLOW_COPY_AND_ASSIGN(Monitor);
318};
319
320class MonitorList {
321 public:
322 MonitorList();
323 ~MonitorList();
324
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700325 void Add(Monitor* m) REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!monitor_list_lock_);
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700326
Mathieu Chartier97509952015-07-13 14:35:43 -0700327 void SweepMonitorList(IsMarkedVisitor* visitor)
Andreas Gampebdf7f1c2016-08-30 16:38:47 -0700328 REQUIRES(!monitor_list_lock_) REQUIRES_SHARED(Locks::mutator_lock_);
Mathieu Chartier90443472015-07-16 20:32:27 -0700329 void DisallowNewMonitors() REQUIRES(!monitor_list_lock_);
330 void AllowNewMonitors() REQUIRES(!monitor_list_lock_);
Mathieu Chartier90443472015-07-16 20:32:27 -0700331 void BroadcastForNewMonitors() REQUIRES(!monitor_list_lock_);
Mathieu Chartier48ab6872014-06-24 11:21:59 -0700332 // Returns how many monitors were deflated.
Mathieu Chartier90443472015-07-16 20:32:27 -0700333 size_t DeflateMonitors() REQUIRES(!monitor_list_lock_) REQUIRES(Locks::mutator_lock_);
Hans Boehm6fe97e02016-05-04 18:35:57 -0700334 size_t Size() REQUIRES(!monitor_list_lock_);
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700335
Mathieu Chartierbad02672014-08-25 13:08:22 -0700336 typedef std::list<Monitor*, TrackingAllocator<Monitor*, kAllocatorTagMonitorList>> Monitors;
337
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700338 private:
Ian Rogers5c597c62014-04-17 16:08:07 -0700339 // During sweeping we may free an object and on a separate thread have an object created using
340 // the newly freed memory. That object may then have its lock-word inflated and a monitor created.
341 // If we allow new monitor registration during sweeping this monitor may be incorrectly freed as
342 // the object wasn't marked when sweeping began.
Mathieu Chartierc11d9b82013-09-19 10:01:59 -0700343 bool allow_new_monitors_ GUARDED_BY(monitor_list_lock_);
Ian Rogers00f7d0e2012-07-19 15:28:27 -0700344 Mutex monitor_list_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
Mathieu Chartierc11d9b82013-09-19 10:01:59 -0700345 ConditionVariable monitor_add_condition_ GUARDED_BY(monitor_list_lock_);
Mathieu Chartierbad02672014-08-25 13:08:22 -0700346 Monitors list_ GUARDED_BY(monitor_list_lock_);
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700347
Ian Rogers7dfb28c2013-08-22 08:18:36 -0700348 friend class Monitor;
Elliott Hughesc33a32b2011-10-11 18:18:07 -0700349 DISALLOW_COPY_AND_ASSIGN(MonitorList);
Elliott Hughes5f791332011-09-15 17:45:30 -0700350};
351
Elliott Hughesf327e072013-01-09 16:01:26 -0800352// Collects information about the current state of an object's monitor.
353// This is very unsafe, and must only be called when all threads are suspended.
354// For use only by the JDWP implementation.
355class MonitorInfo {
356 public:
Andreas Gamped9911ee2017-03-27 13:27:24 -0700357 MonitorInfo() : owner_(nullptr), entry_count_(0) {}
Mathieu Chartierf1d666e2015-09-03 16:13:34 -0700358 MonitorInfo(const MonitorInfo&) = default;
359 MonitorInfo& operator=(const MonitorInfo&) = default;
Mathieu Chartier90443472015-07-16 20:32:27 -0700360 explicit MonitorInfo(mirror::Object* o) REQUIRES(Locks::mutator_lock_);
Elliott Hughesf327e072013-01-09 16:01:26 -0800361
Ian Rogersd9c4fc92013-10-01 19:45:43 -0700362 Thread* owner_;
363 size_t entry_count_;
364 std::vector<Thread*> waiters_;
Elliott Hughesf327e072013-01-09 16:01:26 -0800365};
366
Elliott Hughes5f791332011-09-15 17:45:30 -0700367} // namespace art
368
Brian Carlstromfc0e3212013-07-17 14:40:12 -0700369#endif // ART_RUNTIME_MONITOR_H_