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      1 // Copyright (c) 2012 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/threading/platform_thread.h"
      6 
      7 #include <errno.h>
      8 #include <sys/prctl.h>
      9 #include <sys/resource.h>
     10 
     11 #include "base/android/jni_android.h"
     12 #include "base/android/thread_utils.h"
     13 #include "base/lazy_instance.h"
     14 #include "base/logging.h"
     15 #include "base/threading/thread_id_name_manager.h"
     16 #include "base/tracked_objects.h"
     17 #include "jni/ThreadUtils_jni.h"
     18 
     19 namespace base {
     20 
     21 namespace {
     22 int ThreadNiceValue(ThreadPriority priority) {
     23   // These nice values are taken from Android, which uses nice
     24   // values like linux, but defines some preset nice values.
     25   //   Process.THREAD_PRIORITY_AUDIO = -16
     26   //   Process.THREAD_PRIORITY_BACKGROUND = 10
     27   //   Process.THREAD_PRIORITY_DEFAULT = 0;
     28   //   Process.THREAD_PRIORITY_DISPLAY = -4;
     29   //   Process.THREAD_PRIORITY_FOREGROUND = -2;
     30   //   Process.THREAD_PRIORITY_LESS_FAVORABLE = 1;
     31   //   Process.THREAD_PRIORITY_LOWEST = 19;
     32   //   Process.THREAD_PRIORITY_MORE_FAVORABLE = -1;
     33   //   Process.THREAD_PRIORITY_URGENT_AUDIO = -19;
     34   //   Process.THREAD_PRIORITY_URGENT_DISPLAY = -8;
     35   // We use -6 for display, but we may want to split this
     36   // into urgent (-8) and non-urgent (-4).
     37   static const int threadPriorityAudio = -16;
     38   static const int threadPriorityBackground = 10;
     39   static const int threadPriorityDefault = 0;
     40   static const int threadPriorityDisplay = -6;
     41   switch (priority) {
     42     case kThreadPriority_RealtimeAudio:
     43       return threadPriorityAudio;
     44     case kThreadPriority_Background:
     45       return threadPriorityBackground;
     46     case kThreadPriority_Normal:
     47       return threadPriorityDefault;
     48     case kThreadPriority_Display:
     49       return threadPriorityDisplay;
     50     default:
     51       NOTREACHED() << "Unknown priority.";
     52       return 0;
     53   }
     54 }
     55 } // namespace
     56 
     57 //static
     58 void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
     59                                        ThreadPriority priority) {
     60   // On Android, we set the Audio priority through JNI as Audio priority
     61   // will also allow the process to run while it is backgrounded.
     62   if (priority == kThreadPriority_RealtimeAudio) {
     63     JNIEnv* env = base::android::AttachCurrentThread();
     64     Java_ThreadUtils_setThreadPriorityAudio(env, PlatformThread::CurrentId());
     65     return;
     66   }
     67 
     68   // setpriority(2) will set a thread's priority if it is passed a tid as
     69   // the 'process identifier', not affecting the rest of the threads in the
     70   // process. Setting this priority will only succeed if the user has been
     71   // granted permission to adjust nice values on the system.
     72   DCHECK_NE(handle.id_, kInvalidThreadId);
     73   int kNiceSetting = ThreadNiceValue(priority);
     74   if (setpriority(PRIO_PROCESS, handle.id_, kNiceSetting))
     75     LOG(ERROR) << "Failed to set nice value of thread to " << kNiceSetting;
     76 }
     77 
     78 void PlatformThread::SetName(const char* name) {
     79   ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
     80   tracked_objects::ThreadData::InitializeThreadContext(name);
     81 
     82   // Like linux, on android we can get the thread names to show up in the
     83   // debugger by setting the process name for the LWP.
     84   // We don't want to do this for the main thread because that would rename
     85   // the process, causing tools like killall to stop working.
     86   if (PlatformThread::CurrentId() == getpid())
     87     return;
     88 
     89   // Set the name for the LWP (which gets truncated to 15 characters).
     90   int err = prctl(PR_SET_NAME, name);
     91   if (err < 0 && errno != EPERM)
     92     DPLOG(ERROR) << "prctl(PR_SET_NAME)";
     93 }
     94 
     95 
     96 void InitThreading() {
     97 }
     98 
     99 void InitOnThread() {
    100   // Threads on linux/android may inherit their priority from the thread
    101   // where they were created. This sets all new threads to the default.
    102   PlatformThread::SetThreadPriority(PlatformThread::CurrentHandle(),
    103                                     kThreadPriority_Normal);
    104 }
    105 
    106 void TerminateOnThread() {
    107   base::android::DetachFromVM();
    108 }
    109 
    110 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
    111   return 0;
    112 }
    113 
    114 bool RegisterThreadUtils(JNIEnv* env) {
    115   return RegisterNativesImpl(env);
    116 }
    117 
    118 }  // namespace base
    119