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/*
* Copyright 2021 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.
*/
//#define LOG_NDEBUG 0
#undef LOG_TAG
#define LOG_TAG "BackgroundExecutor"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS
#include <processgroup/sched_policy.h>
#include <pthread.h>
#include <sched.h>
#include <utils/Log.h>
#include <mutex>
#include "BackgroundExecutor.h"
namespace android {
namespace {
void set_thread_priority(bool highPriority) {
set_sched_policy(0, highPriority ? SP_FOREGROUND : SP_BACKGROUND);
struct sched_param param = {0};
param.sched_priority = highPriority ? 2 : 0 /* must be 0 for non-RT */;
sched_setscheduler(gettid(), highPriority ? SCHED_FIFO : SCHED_NORMAL, ¶m);
}
} // anonymous namespace
BackgroundExecutor::BackgroundExecutor(bool highPriority) {
// mSemaphore must be initialized before any calls to
// BackgroundExecutor::sendCallbacks. For this reason, we initialize it
// within the constructor instead of within mThread.
LOG_ALWAYS_FATAL_IF(sem_init(&mSemaphore, 0, 0), "sem_init failed");
mThread = std::thread([&, highPriority]() {
set_thread_priority(highPriority);
while (!mDone) {
LOG_ALWAYS_FATAL_IF(sem_wait(&mSemaphore), "sem_wait failed (%d)", errno);
auto callbacks = mCallbacksQueue.pop();
if (!callbacks) {
continue;
}
for (auto& callback : *callbacks) {
callback();
}
}
});
if (highPriority) {
pthread_setname_np(mThread.native_handle(), "BckgrndExec HP");
} else {
pthread_setname_np(mThread.native_handle(), "BckgrndExec LP");
}
}
BackgroundExecutor::~BackgroundExecutor() {
mDone = true;
LOG_ALWAYS_FATAL_IF(sem_post(&mSemaphore), "sem_post failed");
if (mThread.joinable()) {
mThread.join();
LOG_ALWAYS_FATAL_IF(sem_destroy(&mSemaphore), "sem_destroy failed");
}
}
void BackgroundExecutor::sendCallbacks(Callbacks&& tasks) {
mCallbacksQueue.push(std::move(tasks));
LOG_ALWAYS_FATAL_IF(sem_post(&mSemaphore), "sem_post failed");
}
void BackgroundExecutor::flushQueue() {
std::mutex mutex;
std::condition_variable cv;
bool flushComplete = false;
sendCallbacks({[&]() {
std::scoped_lock lock{mutex};
flushComplete = true;
cv.notify_one();
}});
std::unique_lock<std::mutex> lock{mutex};
cv.wait(lock, [&]() { return flushComplete; });
}
} // namespace android
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