OLD | NEW |
---|---|
(Empty) | |
1 // Copyright 2017 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "base/task_scheduler/scheduler_single_thread_task_runner_manager.h" | |
6 | |
7 #include <algorithm> | |
8 #include <memory> | |
9 #include <string> | |
10 | |
11 #include "base/bind.h" | |
12 #include "base/callback.h" | |
13 #include "base/memory/ptr_util.h" | |
14 #include "base/single_thread_task_runner.h" | |
15 #include "base/strings/stringprintf.h" | |
16 #include "base/synchronization/atomic_flag.h" | |
17 #include "base/task_scheduler/delayed_task_manager.h" | |
18 #include "base/task_scheduler/scheduler_worker.h" | |
19 #include "base/task_scheduler/sequence.h" | |
20 #include "base/task_scheduler/task.h" | |
21 #include "base/task_scheduler/task_tracker.h" | |
22 #include "base/task_scheduler/task_traits.h" | |
23 #include "base/threading/platform_thread.h" | |
24 #include "base/time/time.h" | |
25 | |
26 namespace base { | |
27 namespace internal { | |
28 | |
29 namespace { | |
30 | |
31 // Allows for checking the PlatformThread::CurrentRef() against a set | |
32 // PlatformThreadRef atomically without using locks. | |
33 class AtomicThreadRefChecker { | |
gab
2017/02/23 21:52:10
Don't think this warrants a separate class.
robliao
2017/02/24 18:33:59
The joy of lock-free algorithms is that they're ea
| |
34 public: | |
35 AtomicThreadRefChecker() = default; | |
36 ~AtomicThreadRefChecker() = default; | |
37 | |
38 void Set() { | |
39 thread_ref_ = PlatformThread::CurrentRef(); | |
40 is_set_.Set(); | |
41 } | |
42 | |
43 bool IsCurrentThreadSameAsSetThread() { | |
44 return is_set_.IsSet() && thread_ref_ == PlatformThread::CurrentRef(); | |
45 } | |
46 | |
47 private: | |
48 AtomicFlag is_set_; | |
49 PlatformThreadRef thread_ref_; | |
50 }; | |
51 | |
52 class SchedulerWorkerDelegate : public SchedulerWorker::Delegate { | |
53 public: | |
54 SchedulerWorkerDelegate(const std::string& thread_name) | |
55 : thread_name_(thread_name) {} | |
56 | |
57 // SchedulerWorker::Delegate: | |
58 void OnMainEntry(SchedulerWorker* worker) override { | |
59 thread_ref_checker_.Set(); | |
60 PlatformThread::SetName(thread_name_); | |
61 } | |
62 | |
63 scoped_refptr<Sequence> GetWork(SchedulerWorker* worker) override { | |
64 AutoSchedulerLock auto_lock(sequence_lock_); | |
65 return std::move(sequence_); | |
66 } | |
67 | |
68 void DidRunTask() override {} | |
69 | |
70 void ReEnqueueSequence(scoped_refptr<Sequence> sequence) override { | |
71 AutoSchedulerLock auto_lock(sequence_lock_); | |
72 DCHECK(!sequence_); | |
73 sequence_ = std::move(sequence); | |
74 } | |
75 | |
76 TimeDelta GetSleepTimeout() override { return TimeDelta::Max(); } | |
77 | |
78 bool CanDetach(SchedulerWorker* worker) override { return false; } | |
79 | |
80 void OnDetach() override { NOTREACHED(); } | |
81 | |
82 bool RunsTasksOnCurrentThread() { | |
83 return thread_ref_checker_.IsCurrentThreadSameAsSetThread(); | |
84 } | |
85 | |
86 private: | |
87 const std::string thread_name_; | |
88 | |
89 // Synchronizes access to |sequence_| and handles the fact that | |
90 // ReEnqueueSequence() is called on both the worker thread for reenqueuing | |
91 // the sequence and off of the worker thread to seed the sequence for | |
92 // GetWork(). | |
93 SchedulerLock sequence_lock_; | |
94 scoped_refptr<Sequence> sequence_; | |
95 | |
96 AtomicThreadRefChecker thread_ref_checker_; | |
97 | |
98 DISALLOW_COPY_AND_ASSIGN(SchedulerWorkerDelegate); | |
99 }; | |
100 | |
101 } // namespace | |
102 | |
103 class SchedulerSingleThreadTaskRunnerManager::SchedulerSingleThreadTaskRunner | |
104 : public SingleThreadTaskRunner { | |
105 public: | |
106 // Constructs a SchedulerSingleThreadTaskRunner that indirectly controls the | |
107 // lifetime of a dedicated |worker| for |traits|. | |
108 SchedulerSingleThreadTaskRunner( | |
109 SchedulerSingleThreadTaskRunnerManager* const outer, | |
110 const TaskTraits& traits, | |
111 SchedulerWorker* worker) | |
112 : outer_(outer), traits_(traits), worker_(worker) { | |
113 DCHECK(outer_); | |
114 DCHECK(worker_); | |
115 } | |
116 | |
117 // SingleThreadTaskRunner: | |
118 bool PostDelayedTask(const tracked_objects::Location& from_here, | |
119 const Closure& closure, | |
120 TimeDelta delay) override; | |
121 | |
122 bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here, | |
123 const Closure& closure, | |
124 base::TimeDelta delay) override { | |
125 // Tasks are never nested within the task scheduler. | |
126 return PostDelayedTask(from_here, closure, delay); | |
127 } | |
128 | |
129 bool RunsTasksOnCurrentThread() const override { | |
130 auto delegate = static_cast<SchedulerWorkerDelegate*>(worker_->delegate()); | |
131 return delegate->RunsTasksOnCurrentThread(); | |
132 } | |
133 | |
134 private: | |
135 ~SchedulerSingleThreadTaskRunner() override { | |
136 outer_->UnregisterSchedulerWorker(worker_); | |
137 } | |
138 | |
139 void PostTaskNow(std::unique_ptr<Task> task); | |
140 | |
141 // Sequence for all Tasks posted through this TaskRunner. | |
142 const scoped_refptr<Sequence> sequence_ = new Sequence; | |
143 | |
144 SchedulerSingleThreadTaskRunnerManager* const outer_; | |
145 const TaskTraits traits_; | |
146 SchedulerWorker* const worker_; | |
147 | |
148 DISALLOW_COPY_AND_ASSIGN(SchedulerSingleThreadTaskRunner); | |
149 }; | |
150 | |
151 bool SchedulerSingleThreadTaskRunnerManager::SchedulerSingleThreadTaskRunner:: | |
152 PostDelayedTask(const tracked_objects::Location& from_here, | |
153 const Closure& closure, | |
154 TimeDelta delay) { | |
155 auto task = MakeUnique<Task>(from_here, closure, traits_, delay); | |
156 task->single_thread_task_runner_ref = this; | |
157 | |
158 if (!outer_->task_tracker_->WillPostTask(task.get())) | |
159 return false; | |
160 | |
161 if (task->delayed_run_time.is_null()) { | |
162 PostTaskNow(std::move(task)); | |
163 } else { | |
164 outer_->delayed_task_manager_->AddDelayedTask( | |
165 std::move(task), | |
166 Bind(&SchedulerSingleThreadTaskRunner::PostTaskNow, Unretained(this))); | |
167 } | |
168 return true; | |
169 } | |
170 | |
171 void SchedulerSingleThreadTaskRunnerManager::SchedulerSingleThreadTaskRunner:: | |
172 PostTaskNow(std::unique_ptr<Task> task) { | |
173 const bool sequence_was_empty = sequence_->PushTask(std::move(task)); | |
174 if (sequence_was_empty) { | |
175 auto delegate = static_cast<SchedulerWorkerDelegate*>(worker_->delegate()); | |
176 delegate->ReEnqueueSequence(sequence_); | |
177 worker_->WakeUp(); | |
178 } | |
179 } | |
180 | |
181 SchedulerSingleThreadTaskRunnerManager::SchedulerSingleThreadTaskRunnerManager( | |
182 const std::vector<SchedulerWorkerPoolParams>& worker_pool_params_vector, | |
183 const TaskScheduler::WorkerPoolIndexForTraitsCallback& | |
184 worker_pool_index_for_traits_callback, | |
185 TaskTracker* task_tracker, | |
186 DelayedTaskManager* delayed_task_manager) | |
187 : worker_pool_params_vector_(worker_pool_params_vector), | |
188 worker_pool_index_for_traits_callback_( | |
189 worker_pool_index_for_traits_callback), | |
190 task_tracker_(task_tracker), | |
191 delayed_task_manager_(delayed_task_manager) { | |
192 DCHECK_GT(worker_pool_params_vector_.size(), 0U); | |
193 DCHECK(worker_pool_index_for_traits_callback_); | |
194 DCHECK(task_tracker_); | |
195 DCHECK(delayed_task_manager_); | |
196 } | |
197 | |
198 SchedulerSingleThreadTaskRunnerManager:: | |
199 ~SchedulerSingleThreadTaskRunnerManager() { | |
200 DCHECK(workers_.empty()) << "SchedulerSingleThreadTaskRunners must outlive " | |
201 "SchedulerSingleThreadTaskRunnerManager " | |
202 "otherwise the outstanding " | |
203 "SchedulerSingleThreadTaskRunners will trigger " | |
204 "crashes."; | |
205 } | |
206 | |
207 scoped_refptr<SingleThreadTaskRunner> | |
208 SchedulerSingleThreadTaskRunnerManager::CreateSingleThreadTaskRunnerWithTraits( | |
209 const TaskTraits& traits) { | |
210 size_t index = worker_pool_index_for_traits_callback_.Run(traits); | |
211 DCHECK_LT(index, worker_pool_params_vector_.size()); | |
212 return new SchedulerSingleThreadTaskRunner( | |
213 this, traits, | |
214 CreateAndRegisterSchedulerWorker(worker_pool_params_vector_[index])); | |
215 } | |
216 | |
217 void SchedulerSingleThreadTaskRunnerManager::JoinForTesting() { | |
218 decltype(workers_) local_workers; | |
219 { | |
220 AutoSchedulerLock auto_lock(workers_lock_); | |
221 local_workers = std::move(workers_); | |
222 } | |
223 | |
224 for (const auto& worker : local_workers) | |
225 worker->JoinForTesting(); | |
226 | |
227 { | |
228 AutoSchedulerLock auto_lock(workers_lock_); | |
229 DCHECK(workers_.empty()) | |
230 << "New worker(s) unexpectedly registered during join."; | |
231 workers_ = std::move(local_workers); | |
232 } | |
233 } | |
234 | |
235 SchedulerWorker* | |
236 SchedulerSingleThreadTaskRunnerManager::CreateAndRegisterSchedulerWorker( | |
237 const SchedulerWorkerPoolParams& params) { | |
238 AutoSchedulerLock auto_lock(workers_lock_); | |
239 int id = next_worker_id_++; | |
240 auto delegate = MakeUnique<SchedulerWorkerDelegate>(base::StringPrintf( | |
241 "TaskSchedulerSingleThreadWorker%d%s", id, params.name().c_str())); | |
242 workers_.emplace_back(SchedulerWorker::Create( | |
243 params.priority_hint(), std::move(delegate), task_tracker_, | |
244 SchedulerWorker::InitialState::DETACHED)); | |
245 return workers_.back().get(); | |
246 } | |
247 | |
248 void SchedulerSingleThreadTaskRunnerManager::UnregisterSchedulerWorker( | |
249 SchedulerWorker* worker) { | |
250 // Cleanup uses a SchedulerLock, so call Cleanup() after releasing | |
251 // |workers_lock_|. | |
252 scoped_refptr<SchedulerWorker> worker_to_destroy; | |
253 { | |
254 AutoSchedulerLock auto_lock(workers_lock_); | |
255 | |
256 // We might be joining, so no-op this if |workers_| is empty. | |
257 if (workers_.empty()) | |
258 return; | |
259 | |
260 auto worker_iter = | |
261 std::find_if(workers_.begin(), workers_.end(), | |
262 [worker](const scoped_refptr<SchedulerWorker>& candidate) { | |
263 return candidate.get() == worker; | |
264 }); | |
265 DCHECK(worker_iter != workers_.end()); | |
266 worker_to_destroy = std::move(*worker_iter); | |
267 workers_.erase(worker_iter); | |
268 } | |
269 worker_to_destroy->Cleanup(); | |
270 } | |
271 | |
272 } // namespace internal | |
273 } // namespace base | |
OLD | NEW |