base/threading/platform_thread_linux.cc

   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/threading/platform_thread_internal_posix.h"
  13 #include "base/threading/thread_id_name_manager.h"
  14 #include "base/tracked_objects.h"
  15
  16 #if !defined(OS_NACL)
  17 #include <pthread.h>
  18 #include <sys/prctl.h>
  19 #include <sys/types.h>
  20 #include <unistd.h>
  21 #endif
  22
  23 namespace base {
  24
  25 namespace internal {
  26
  27 namespace {
  28 #if !defined(OS_NACL)
  29 const struct sched_param kRealTimePrio = {8};
  30 const struct sched_param kResetPrio = {0};
  31 #endif
  32 }  // namespace
  33
  34 const ThreadPriorityToNiceValuePair kThreadPriorityToNiceValueMap[4] = {
  35     {ThreadPriority::BACKGROUND, 10},
  36     {ThreadPriority::NORMAL, 0},
  37     {ThreadPriority::DISPLAY, -6},
  38     {ThreadPriority::REALTIME_AUDIO, -10},
  39 };
  40
  41 bool SetThreadPriorityForPlatform(PlatformThreadHandle handle,
  42                                   ThreadPriority priority) {
  43 #if !defined(OS_NACL)
  44   ThreadPriority current_priority;
  45   if (priority != ThreadPriority::REALTIME_AUDIO &&
  46       GetThreadPriorityForPlatform(handle, &current_priority) &&
  47       current_priority == ThreadPriority::REALTIME_AUDIO) {
  48     // If the pthread's round-robin scheduler is already enabled, and the new
  49     // priority will use setpriority() instead, the pthread scheduler should be
  50     // reset to use SCHED_OTHER so that setpriority() just works.
  51     pthread_setschedparam(pthread_self(), SCHED_OTHER, &kResetPrio);
  52     return false;
  53   }
  54   // TODO(gab): Assess the correctness of using |pthread_self()| below instead
  55   // of |handle|. http://crbug.com/468793.
  56   return priority == ThreadPriority::REALTIME_AUDIO  &&
  57          pthread_setschedparam(pthread_self(), SCHED_RR, &kRealTimePrio) == 0;
  58 #else
  59   return false;
  60 #endif
  61 }
  62
  63 bool GetThreadPriorityForPlatform(PlatformThreadHandle handle,
  64                                   ThreadPriority* priority) {
  65 #if !defined(OS_NACL)
  66   int maybe_sched_rr = 0;
  67   struct sched_param maybe_realtime_prio = {0};
  68   // TODO(gab): Assess the correctness of using |pthread_self()| below instead
  69   // of |handle|. http://crbug.com/468793.
  70   if (pthread_getschedparam(pthread_self(), &maybe_sched_rr,
  71                             &maybe_realtime_prio) == 0 &&
  72       maybe_sched_rr == SCHED_RR &&
  73       maybe_realtime_prio.sched_priority == kRealTimePrio.sched_priority) {
  74     *priority = ThreadPriority::REALTIME_AUDIO;
  75     return true;
  76   }
  77 #endif
  78   return false;
  79 }
  80
  81 }  // namespace internal
  82
  83 // static
  84 void PlatformThread::SetName(const std::string& name) {
  85   ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
  86   tracked_objects::ThreadData::InitializeThreadContext(name);
  87
  88 #if !defined(OS_NACL)
  89   // On linux we can get the thread names to show up in the debugger by setting
  90   // the process name for the LWP.  We don't want to do this for the main
  91   // thread because that would rename the process, causing tools like killall
  92   // to stop working.
  93   if (PlatformThread::CurrentId() == getpid())
  94     return;
  95
  96   // http://0pointer.de/blog/projects/name-your-threads.html
  97   // Set the name for the LWP (which gets truncated to 15 characters).
  98   // Note that glibc also has a 'pthread_setname_np' api, but it may not be
  99   // available everywhere and it's only benefit over using prctl directly is
 100   // that it can set the name of threads other than the current thread.
 101   int err = prctl(PR_SET_NAME, name.c_str());
 102   // We expect EPERM failures in sandboxed processes, just ignore those.
 103   if (err < 0 && errno != EPERM)
 104     DPLOG(ERROR) << "prctl(PR_SET_NAME)";
 105 #endif  //  !defined(OS_NACL)
 106 }
 107
 108 void InitThreading() {}
 109
 110 void InitOnThread() {}
 111
 112 void TerminateOnThread() {}
 113
 114 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
 115 #if !defined(THREAD_SANITIZER)
 116   return 0;
 117 #else
 118   // ThreadSanitizer bloats the stack heavily. Evidence has been that the
 119   // default stack size isn't enough for some browser tests.
 120   return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).
 121 #endif
 122 }
 123
 124 }  // namespace base