upload android base code part3

android/art/runtime/thread_pool.cc

@@ -0,0 +1,254 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "thread_pool.h"
+
+#include <pthread.h>
+
+#include <sys/mman.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include "android-base/stringprintf.h"
+
+#include "base/bit_utils.h"
+#include "base/casts.h"
+#include "base/logging.h"
+#include "base/stl_util.h"
+#include "base/time_utils.h"
+#include "runtime.h"
+#include "thread-current-inl.h"
+
+namespace art {
+
+using android::base::StringPrintf;
+
+static constexpr bool kMeasureWaitTime = false;
+
+ThreadPoolWorker::ThreadPoolWorker(ThreadPool* thread_pool, const std::string& name,
+                                   size_t stack_size)
+    : thread_pool_(thread_pool),
+      name_(name) {
+  // Add an inaccessible page to catch stack overflow.
+  stack_size += kPageSize;
+  std::string error_msg;
+  stack_.reset(MemMap::MapAnonymous(name.c_str(), nullptr, stack_size, PROT_READ | PROT_WRITE,
+                                    false, false, &error_msg));
+  CHECK(stack_.get() != nullptr) << error_msg;
+  CHECK_ALIGNED(stack_->Begin(), kPageSize);
+  int mprotect_result = mprotect(stack_->Begin(), kPageSize, PROT_NONE);
+  CHECK_EQ(mprotect_result, 0) << "Failed to mprotect() bottom page of thread pool worker stack.";
+  const char* reason = "new thread pool worker thread";
+  pthread_attr_t attr;
+  CHECK_PTHREAD_CALL(pthread_attr_init, (&attr), reason);
+  CHECK_PTHREAD_CALL(pthread_attr_setstack, (&attr, stack_->Begin(), stack_->Size()), reason);
+  CHECK_PTHREAD_CALL(pthread_create, (&pthread_, &attr, &Callback, this), reason);
+  CHECK_PTHREAD_CALL(pthread_attr_destroy, (&attr), reason);
+}
+
+ThreadPoolWorker::~ThreadPoolWorker() {
+  CHECK_PTHREAD_CALL(pthread_join, (pthread_, nullptr), "thread pool worker shutdown");
+}
+
+void ThreadPoolWorker::SetPthreadPriority(int priority) {
+  CHECK_GE(priority, PRIO_MIN);
+  CHECK_LE(priority, PRIO_MAX);
+#if defined(ART_TARGET_ANDROID)
+  int result = setpriority(PRIO_PROCESS, pthread_gettid_np(pthread_), priority);
+  if (result != 0) {
+    PLOG(ERROR) << "Failed to setpriority to :" << priority;
+  }
+#else
+  UNUSED(priority);
+#endif
+}
+
+void ThreadPoolWorker::Run() {
+  Thread* self = Thread::Current();
+  Task* task = nullptr;
+  thread_pool_->creation_barier_.Wait(self);
+  while ((task = thread_pool_->GetTask(self)) != nullptr) {
+    task->Run(self);
+    task->Finalize();
+  }
+}
+
+void* ThreadPoolWorker::Callback(void* arg) {
+  ThreadPoolWorker* worker = reinterpret_cast<ThreadPoolWorker*>(arg);
+  Runtime* runtime = Runtime::Current();
+  CHECK(runtime->AttachCurrentThread(worker->name_.c_str(),
+                                     true,
+                                     nullptr,
+                                     worker->thread_pool_->create_peers_));
+  worker->thread_ = Thread::Current();
+  // Thread pool workers cannot call into java.
+  worker->thread_->SetCanCallIntoJava(false);
+  // Do work until its time to shut down.
+  worker->Run();
+  runtime->DetachCurrentThread();
+  return nullptr;
+}
+
+void ThreadPool::AddTask(Thread* self, Task* task) {
+  MutexLock mu(self, task_queue_lock_);
+  tasks_.push_back(task);
+  // If we have any waiters, signal one.
+  if (started_ && waiting_count_ != 0) {
+    task_queue_condition_.Signal(self);
+  }
+}
+
+void ThreadPool::RemoveAllTasks(Thread* self) {
+  MutexLock mu(self, task_queue_lock_);
+  tasks_.clear();
+}
+
+ThreadPool::ThreadPool(const char* name, size_t num_threads, bool create_peers)
+  : name_(name),
+    task_queue_lock_("task queue lock"),
+    task_queue_condition_("task queue condition", task_queue_lock_),
+    completion_condition_("task completion condition", task_queue_lock_),
+    started_(false),
+    shutting_down_(false),
+    waiting_count_(0),
+    start_time_(0),
+    total_wait_time_(0),
+    // Add one since the caller of constructor waits on the barrier too.
+    creation_barier_(num_threads + 1),
+    max_active_workers_(num_threads),
+    create_peers_(create_peers) {
+  Thread* self = Thread::Current();
+  while (GetThreadCount() < num_threads) {
+    const std::string worker_name = StringPrintf("%s worker thread %zu", name_.c_str(),
+                                                 GetThreadCount());
+    threads_.push_back(
+        new ThreadPoolWorker(this, worker_name, ThreadPoolWorker::kDefaultStackSize));
+  }
+  // Wait for all of the threads to attach.
+  creation_barier_.Wait(self);
+}
+
+void ThreadPool::SetMaxActiveWorkers(size_t threads) {
+  MutexLock mu(Thread::Current(), task_queue_lock_);
+  CHECK_LE(threads, GetThreadCount());
+  max_active_workers_ = threads;
+}
+
+ThreadPool::~ThreadPool() {
+  {
+    Thread* self = Thread::Current();
+    MutexLock mu(self, task_queue_lock_);
+    // Tell any remaining workers to shut down.
+    shutting_down_ = true;
+    // Broadcast to everyone waiting.
+    task_queue_condition_.Broadcast(self);
+    completion_condition_.Broadcast(self);
+  }
+  // Wait for the threads to finish.
+  STLDeleteElements(&threads_);
+}
+
+void ThreadPool::StartWorkers(Thread* self) {
+  MutexLock mu(self, task_queue_lock_);
+  started_ = true;
+  task_queue_condition_.Broadcast(self);
+  start_time_ = NanoTime();
+  total_wait_time_ = 0;
+}
+
+void ThreadPool::StopWorkers(Thread* self) {
+  MutexLock mu(self, task_queue_lock_);
+  started_ = false;
+}
+
+Task* ThreadPool::GetTask(Thread* self) {
+  MutexLock mu(self, task_queue_lock_);
+  while (!IsShuttingDown()) {
+    const size_t thread_count = GetThreadCount();
+    // Ensure that we don't use more threads than the maximum active workers.
+    const size_t active_threads = thread_count - waiting_count_;
+    // <= since self is considered an active worker.
+    if (active_threads <= max_active_workers_) {
+      Task* task = TryGetTaskLocked();
+      if (task != nullptr) {
+        return task;
+      }
+    }
+
+    ++waiting_count_;
+    if (waiting_count_ == GetThreadCount() && !HasOutstandingTasks()) {
+      // We may be done, lets broadcast to the completion condition.
+      completion_condition_.Broadcast(self);
+    }
+    const uint64_t wait_start = kMeasureWaitTime ? NanoTime() : 0;
+    task_queue_condition_.Wait(self);
+    if (kMeasureWaitTime) {
+      const uint64_t wait_end = NanoTime();
+      total_wait_time_ += wait_end - std::max(wait_start, start_time_);
+    }
+    --waiting_count_;
+  }
+
+  // We are shutting down, return null to tell the worker thread to stop looping.
+  return nullptr;
+}
+
+Task* ThreadPool::TryGetTask(Thread* self) {
+  MutexLock mu(self, task_queue_lock_);
+  return TryGetTaskLocked();
+}
+
+Task* ThreadPool::TryGetTaskLocked() {
+  if (HasOutstandingTasks()) {
+    Task* task = tasks_.front();
+    tasks_.pop_front();
+    return task;
+  }
+  return nullptr;
+}
+
+void ThreadPool::Wait(Thread* self, bool do_work, bool may_hold_locks) {
+  if (do_work) {
+    CHECK(!create_peers_);
+    Task* task = nullptr;
+    while ((task = TryGetTask(self)) != nullptr) {
+      task->Run(self);
+      task->Finalize();
+    }
+  }
+  // Wait until each thread is waiting and the task list is empty.
+  MutexLock mu(self, task_queue_lock_);
+  while (!shutting_down_ && (waiting_count_ != GetThreadCount() || HasOutstandingTasks())) {
+    if (!may_hold_locks) {
+      completion_condition_.Wait(self);
+    } else {
+      completion_condition_.WaitHoldingLocks(self);
+    }
+  }
+}
+
+size_t ThreadPool::GetTaskCount(Thread* self) {
+  MutexLock mu(self, task_queue_lock_);
+  return tasks_.size();
+}
+
+void ThreadPool::SetPthreadPriority(int priority) {
+  for (ThreadPoolWorker* worker : threads_) {
+    worker->SetPthreadPriority(priority);
+  }
+}
+
+}  // namespace art