1 // Copyright 2017 The Chromium Authors 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/thread_pool/environment_config.h" 6 7 #include "base/base_switches.h" 8 #include "base/command_line.h" 9 #include "base/synchronization/lock.h" 10 #include "base/threading/platform_thread.h" 11 #include "build/build_config.h" 12 13 namespace base { 14 namespace internal { 15 16 namespace { 17 CanUseBackgroundThreadTypeForWorkerThreadImpl()18bool CanUseBackgroundThreadTypeForWorkerThreadImpl() { 19 // Commandline flag overrides (e.g. for experiments). Note that it may not be 20 // initialized yet, e.g. in cronet. 21 if (CommandLine::InitializedForCurrentProcess() && 22 CommandLine::ForCurrentProcess()->HasSwitch( 23 switches::kEnableBackgroundThreadPool)) { 24 return true; 25 } 26 27 // When Lock doesn't handle multiple thread priorities, run all 28 // WorkerThread with a normal priority to avoid priority inversion when a 29 // thread running with a normal priority tries to acquire a lock held by a 30 // thread running with a background priority. 31 if (!Lock::HandlesMultipleThreadPriorities()) 32 return false; 33 34 #if !BUILDFLAG(IS_ANDROID) 35 // When thread type can't be increased to kNormal, run all threads with a 36 // kNormal thread type to avoid priority inversions on shutdown 37 // (ThreadPoolImpl increases kBackground threads type to kNormal on shutdown 38 // while resolving remaining shutdown blocking tasks). 39 // 40 // This is ignored on Android, because it doesn't have a clean shutdown phase. 41 if (!PlatformThread::CanChangeThreadType(ThreadType::kBackground, 42 ThreadType::kDefault)) 43 return false; 44 #endif // BUILDFLAG(IS_ANDROID) 45 46 return true; 47 } 48 CanUseUtilityThreadTypeForWorkerThreadImpl()49bool CanUseUtilityThreadTypeForWorkerThreadImpl() { 50 #if !BUILDFLAG(IS_ANDROID) 51 // Same as CanUseBackgroundThreadTypeForWorkerThreadImpl() 52 if (!PlatformThread::CanChangeThreadType(ThreadType::kUtility, 53 ThreadType::kDefault)) 54 return false; 55 #endif // BUILDFLAG(IS_ANDROID) 56 57 return true; 58 } 59 60 } // namespace 61 CanUseBackgroundThreadTypeForWorkerThread()62bool CanUseBackgroundThreadTypeForWorkerThread() { 63 static const bool can_use_background_thread_type_for_worker_thread = 64 CanUseBackgroundThreadTypeForWorkerThreadImpl(); 65 return can_use_background_thread_type_for_worker_thread; 66 } 67 CanUseUtilityThreadTypeForWorkerThread()68bool CanUseUtilityThreadTypeForWorkerThread() { 69 static const bool can_use_utility_thread_type_for_worker_thread = 70 CanUseUtilityThreadTypeForWorkerThreadImpl(); 71 return can_use_utility_thread_type_for_worker_thread; 72 } 73 74 } // namespace internal 75 } // namespace base 76