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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 <sched.h>
      9 
     10 #include "base/lazy_instance.h"
     11 #include "base/logging.h"
     12 #include "base/memory/scoped_ptr.h"
     13 #include "base/safe_strerror_posix.h"
     14 #include "base/threading/thread_id_name_manager.h"
     15 #include "base/threading/thread_restrictions.h"
     16 #include "base/tracked_objects.h"
     17 
     18 #if !defined(OS_NACL)
     19 #include <sys/prctl.h>
     20 #include <sys/resource.h>
     21 #include <sys/syscall.h>
     22 #include <sys/time.h>
     23 #include <unistd.h>
     24 #endif
     25 
     26 namespace base {
     27 
     28 namespace {
     29 int ThreadNiceValue(ThreadPriority priority) {
     30   static const int threadPriorityAudio = -10;
     31   static const int threadPriorityBackground = 10;
     32   static const int threadPriorityDefault = 0;
     33   static const int threadPriorityDisplay = -6;
     34   switch (priority) {
     35     case kThreadPriority_RealtimeAudio:
     36       return threadPriorityAudio;
     37     case kThreadPriority_Background:
     38       return threadPriorityBackground;
     39     case kThreadPriority_Normal:
     40       return threadPriorityDefault;
     41     case kThreadPriority_Display:
     42       return threadPriorityDisplay;
     43     default:
     44       NOTREACHED() << "Unknown priority.";
     45       return 0;
     46   }
     47 }
     48 } // namespace
     49 
     50 // static
     51 void PlatformThread::SetName(const char* name) {
     52   ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
     53   tracked_objects::ThreadData::InitializeThreadContext(name);
     54 
     55 #ifndef OS_NACL
     56   // On linux we can get the thread names to show up in the debugger by setting
     57   // the process name for the LWP.  We don't want to do this for the main
     58   // thread because that would rename the process, causing tools like killall
     59   // to stop working.
     60   if (PlatformThread::CurrentId() == getpid())
     61     return;
     62 
     63   // http://0pointer.de/blog/projects/name-your-threads.html
     64   // Set the name for the LWP (which gets truncated to 15 characters).
     65   // Note that glibc also has a 'pthread_setname_np' api, but it may not be
     66   // available everywhere and it's only benefit over using prctl directly is
     67   // that it can set the name of threads other than the current thread.
     68   int err = prctl(PR_SET_NAME, name);
     69   // We expect EPERM failures in sandboxed processes, just ignore those.
     70   if (err < 0 && errno != EPERM)
     71     DPLOG(ERROR) << "prctl(PR_SET_NAME)";
     72 #endif
     73 }
     74 
     75 // static
     76 void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
     77                                        ThreadPriority priority) {
     78 #if !defined(OS_NACL)
     79   if (priority == kThreadPriority_RealtimeAudio) {
     80     const int kRealTimePrio = 8;
     81 
     82     struct sched_param sched_param;
     83     memset(&sched_param, 0, sizeof(sched_param));
     84     sched_param.sched_priority = kRealTimePrio;
     85 
     86     if (pthread_setschedparam(pthread_self(), SCHED_RR, &sched_param) == 0) {
     87       // Got real time priority, no need to set nice level.
     88       return;
     89     }
     90   }
     91 
     92   // setpriority(2) will set a thread's priority if it is passed a tid as
     93   // the 'process identifier', not affecting the rest of the threads in the
     94   // process. Setting this priority will only succeed if the user has been
     95   // granted permission to adjust nice values on the system.
     96   DCHECK_NE(handle.id_, kInvalidThreadId);
     97   int kNiceSetting = ThreadNiceValue(priority);
     98   if (setpriority(PRIO_PROCESS, handle.id_, kNiceSetting))
     99     LOG(ERROR) << "Failed to set nice value of thread to " << kNiceSetting;
    100 #endif  // !OS_NACL
    101 }
    102 
    103 void InitThreading() {
    104 }
    105 
    106 void InitOnThread() {
    107 }
    108 
    109 void TerminateOnThread() {
    110 }
    111 
    112 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
    113   return 0;
    114 }
    115 
    116 }  // namespace base
    117