1 // Copyright 2017 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/task_scheduler/environment_config.h" 6 7 #include "base/synchronization/lock.h" 8 #include "base/threading/platform_thread.h" 9 #include "build/build_config.h" 10 11 namespace base { 12 namespace internal { 13 14 size_t GetEnvironmentIndexForTraits(const TaskTraits& traits) { 15 const bool is_background = 16 traits.priority() == base::TaskPriority::BACKGROUND; 17 if (traits.may_block() || traits.with_base_sync_primitives()) 18 return is_background ? BACKGROUND_BLOCKING : FOREGROUND_BLOCKING; 19 return is_background ? BACKGROUND : FOREGROUND; 20 } 21 22 bool CanUseBackgroundPriorityForSchedulerWorker() { 23 // When Lock doesn't handle multiple thread priorities, run all 24 // SchedulerWorker with a normal priority to avoid priority inversion when a 25 // thread running with a normal priority tries to acquire a lock held by a 26 // thread running with a background priority. 27 if (!Lock::HandlesMultipleThreadPriorities()) 28 return false; 29 30 #if !defined(OS_ANDROID) 31 // When thread priority can't be increased, run all threads with a normal 32 // priority to avoid priority inversions on shutdown (TaskScheduler increases 33 // background threads priority to normal on shutdown while resolving remaining 34 // shutdown blocking tasks). 35 // 36 // This is ignored on Android, because it doesn't have a clean shutdown phase. 37 if (!PlatformThread::CanIncreaseCurrentThreadPriority()) 38 return false; 39 #endif // defined(OS_ANDROID) 40 41 return true; 42 } 43 44 } // namespace internal 45 } // namespace base 46
