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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/threading/platform_thread.h"
#include <atomic>
#include <memory>
#include "base/feature_list.h"
namespace base {
namespace {
// Whether thread priorities should be used. When disabled,
// PlatformThread::SetCurrentThreadPriority() no-ops.
const Feature kThreadPrioritiesFeature{"ThreadPriorities",
FEATURE_ENABLED_BY_DEFAULT};
// Whether thread priorities should be used.
//
// PlatformThread::SetCurrentThreadPriority() doesn't query the state of the
// feature directly because FeatureList initialization is not always
// synchronized with PlatformThread::SetCurrentThreadPriority().
std::atomic<bool> g_use_thread_priorities(true);
} // namespace
// static
void PlatformThread::SetCurrentThreadPriority(ThreadPriority priority) {
if (g_use_thread_priorities.load())
SetCurrentThreadPriorityImpl(priority);
}
namespace internal {
void InitializeThreadPrioritiesFeature() {
// A DCHECK is triggered on FeatureList initialization if the state of a
// feature has been checked before. To avoid triggering this DCHECK in unit
// tests that call this before initializing the FeatureList, only check the
// state of the feature if the FeatureList is initialized.
if (FeatureList::GetInstance() &&
!FeatureList::IsEnabled(kThreadPrioritiesFeature)) {
g_use_thread_priorities.store(false);
}
}
} // namespace internal
} // namespace base