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