1 /*
2 * Copyright (C) 2014 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
17 #include "task_processor.h"
18
19 #include "base/time_utils.h"
20 #include "scoped_thread_state_change-inl.h"
21
22 namespace art {
23 namespace gc {
24
TaskProcessor()25 TaskProcessor::TaskProcessor()
26 : lock_(new Mutex("Task processor lock", kReferenceProcessorLock)), is_running_(false),
27 running_thread_(nullptr) {
28 // Piggyback off the reference processor lock level.
29 cond_.reset(new ConditionVariable("Task processor condition", *lock_));
30 }
31
~TaskProcessor()32 TaskProcessor::~TaskProcessor() {
33 delete lock_;
34 }
35
AddTask(Thread * self,HeapTask * task)36 void TaskProcessor::AddTask(Thread* self, HeapTask* task) {
37 ScopedThreadStateChange tsc(self, kBlocked);
38 MutexLock mu(self, *lock_);
39 tasks_.insert(task);
40 cond_->Signal(self);
41 }
42
GetTask(Thread * self)43 HeapTask* TaskProcessor::GetTask(Thread* self) {
44 ScopedThreadStateChange tsc(self, kBlocked);
45 MutexLock mu(self, *lock_);
46 while (true) {
47 if (tasks_.empty()) {
48 if (!is_running_) {
49 return nullptr;
50 }
51 cond_->Wait(self); // Empty queue, wait until we are signalled.
52 } else {
53 // Non empty queue, look at the top element and see if we are ready to run it.
54 const uint64_t current_time = NanoTime();
55 HeapTask* task = *tasks_.begin();
56 // If we are shutting down, return the task right away without waiting. Otherwise return the
57 // task if it is late enough.
58 uint64_t target_time = task->GetTargetRunTime();
59 if (!is_running_ || target_time <= current_time) {
60 tasks_.erase(tasks_.begin());
61 return task;
62 }
63 DCHECK_GT(target_time, current_time);
64 // Wait untl we hit the target run time.
65 const uint64_t delta_time = target_time - current_time;
66 const uint64_t ms_delta = NsToMs(delta_time);
67 const uint64_t ns_delta = delta_time - MsToNs(ms_delta);
68 cond_->TimedWait(self, static_cast<int64_t>(ms_delta), static_cast<int32_t>(ns_delta));
69 }
70 }
71 UNREACHABLE();
72 }
73
UpdateTargetRunTime(Thread * self,HeapTask * task,uint64_t new_target_time)74 void TaskProcessor::UpdateTargetRunTime(Thread* self, HeapTask* task, uint64_t new_target_time) {
75 MutexLock mu(self, *lock_);
76 // Find the task.
77 auto range = tasks_.equal_range(task);
78 for (auto it = range.first; it != range.second; ++it) {
79 if (*it == task) {
80 // Check if the target time was updated, if so re-insert then wait.
81 if (new_target_time != task->GetTargetRunTime()) {
82 tasks_.erase(it);
83 task->SetTargetRunTime(new_target_time);
84 tasks_.insert(task);
85 // If we became the first task then we may need to signal since we changed the task that we
86 // are sleeping on.
87 if (*tasks_.begin() == task) {
88 cond_->Signal(self);
89 }
90 return;
91 }
92 }
93 }
94 }
95
IsRunning() const96 bool TaskProcessor::IsRunning() const {
97 MutexLock mu(Thread::Current(), *lock_);
98 return is_running_;
99 }
100
GetRunningThread() const101 Thread* TaskProcessor::GetRunningThread() const {
102 MutexLock mu(Thread::Current(), *lock_);
103 return running_thread_;
104 }
105
Stop(Thread * self)106 void TaskProcessor::Stop(Thread* self) {
107 MutexLock mu(self, *lock_);
108 is_running_ = false;
109 running_thread_ = nullptr;
110 cond_->Broadcast(self);
111 }
112
Start(Thread * self)113 void TaskProcessor::Start(Thread* self) {
114 MutexLock mu(self, *lock_);
115 is_running_ = true;
116 running_thread_ = self;
117 }
118
RunAllTasks(Thread * self)119 void TaskProcessor::RunAllTasks(Thread* self) {
120 while (true) {
121 // Wait and get a task, may be interrupted.
122 HeapTask* task = GetTask(self);
123 if (task != nullptr) {
124 task->Run(self);
125 task->Finalize();
126 } else if (!IsRunning()) {
127 break;
128 }
129 }
130 }
131
132 } // namespace gc
133 } // namespace art
134