Home | History | Annotate | Download | only in threading 
      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 
     30 int ThreadNiceValue(ThreadPriority priority) {
     31   switch (priority) {
     32     case kThreadPriority_RealtimeAudio:
     33       return -10;
     34     case kThreadPriority_Background:
     35       return 10;
     36     case kThreadPriority_Normal:
     37       return 0;
     38     case kThreadPriority_Display:
     39       return -6;
     40     default:
     41       NOTREACHED() << "Unknown priority.";
     42       return 0;
     43   }
     44 }
     45 
     46 }  // namespace
     47 
     48 // static
     49 void PlatformThread::SetName(const char* name) {
     50   ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
     51   tracked_objects::ThreadData::InitializeThreadContext(name);
     52 
     53 #if !defined(OS_NACL)
     54   // On linux we can get the thread names to show up in the debugger by setting
     55   // the process name for the LWP.  We don't want to do this for the main
     56   // thread because that would rename the process, causing tools like killall
     57   // to stop working.
     58   if (PlatformThread::CurrentId() == getpid())
     59     return;
     60 
     61   // http://0pointer.de/blog/projects/name-your-threads.html
     62   // Set the name for the LWP (which gets truncated to 15 characters).
     63   // Note that glibc also has a 'pthread_setname_np' api, but it may not be
     64   // available everywhere and it's only benefit over using prctl directly is
     65   // that it can set the name of threads other than the current thread.
     66   int err = prctl(PR_SET_NAME, name);
     67   // We expect EPERM failures in sandboxed processes, just ignore those.
     68   if (err < 0 && errno != EPERM)
     69     DPLOG(ERROR) << "prctl(PR_SET_NAME)";
     70 #endif  //  !defined(OS_NACL)
     71 }
     72 
     73 // static
     74 void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
     75                                        ThreadPriority priority) {
     76 #if !defined(OS_NACL)
     77   if (priority == kThreadPriority_RealtimeAudio) {
     78     const struct sched_param kRealTimePrio = {8};
     79     if (pthread_setschedparam(pthread_self(), SCHED_RR, &kRealTimePrio) == 0) {
     80       // Got real time priority, no need to set nice level.
     81       return;
     82     }
     83   }
     84 
     85   // setpriority(2) should change the whole thread group's (i.e. process)
     86   // priority. however, on linux it will only change the target thread's
     87   // priority. see the bugs section in
     88   // http://man7.org/linux/man-pages/man2/getpriority.2.html.
     89   // we prefer using 0 rather than the current thread id since they are
     90   // equivalent but it makes sandboxing easier (https://crbug.com/399473).
     91   DCHECK_NE(handle.id_, kInvalidThreadId);
     92   const int kNiceSetting = ThreadNiceValue(priority);
     93   const PlatformThreadId current_id = PlatformThread::CurrentId();
     94   if (setpriority(PRIO_PROCESS,
     95                   handle.id_ == current_id ? 0 : handle.id_,
     96                   kNiceSetting)) {
     97     DVPLOG(1) << "Failed to set nice value of thread (" << handle.id_ << ") to "
     98               << kNiceSetting;
     99   }
    100 #endif  //  !defined(OS_NACL)
    101 }
    102 
    103 void InitThreading() {}
    104 
    105 void InitOnThread() {}
    106 
    107 void TerminateOnThread() {}
    108 
    109 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
    110 #if !defined(THREAD_SANITIZER)
    111   return 0;
    112 #else
    113   // ThreadSanitizer bloats the stack heavily. Evidence has been that the
    114   // default stack size isn't enough for some browser tests.
    115   return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).
    116 #endif
    117 }
    118 
    119 }  // namespace base
    120