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-rw-r--r--security/sandbox/chromium/base/threading/platform_thread.cc51
1 files changed, 51 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/threading/platform_thread.cc b/security/sandbox/chromium/base/threading/platform_thread.cc
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+++ b/security/sandbox/chromium/base/threading/platform_thread.cc
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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