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| 1 // Copyright (c) 2010 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/logging.h" |
| 11 #include "base/safe_strerror_posix.h" |
| 12 #include "base/scoped_ptr.h" |
| 13 #include "base/threading/thread_restrictions.h" |
| 14 |
| 15 #if defined(OS_MACOSX) |
| 16 #include <mach/mach.h> |
| 17 #include <sys/resource.h> |
| 18 #include <algorithm> |
| 19 #endif |
| 20 |
| 21 #if defined(OS_LINUX) |
| 22 #include <dlfcn.h> |
| 23 #include <sys/prctl.h> |
| 24 #include <sys/syscall.h> |
| 25 #include <unistd.h> |
| 26 #endif |
| 27 |
| 28 #if defined(OS_NACL) |
| 29 #include <sys/nacl_syscalls.h> |
| 30 #endif |
| 31 |
| 32 namespace base { |
| 33 |
| 34 #if defined(OS_MACOSX) |
| 35 void InitThreading(); |
| 36 #endif |
| 37 |
| 38 namespace { |
| 39 |
| 40 struct ThreadParams { |
| 41 PlatformThread::Delegate* delegate; |
| 42 bool joinable; |
| 43 }; |
| 44 |
| 45 void* ThreadFunc(void* params) { |
| 46 ThreadParams* thread_params = static_cast<ThreadParams*>(params); |
| 47 PlatformThread::Delegate* delegate = thread_params->delegate; |
| 48 if (!thread_params->joinable) |
| 49 base::ThreadRestrictions::SetSingletonAllowed(false); |
| 50 delete thread_params; |
| 51 delegate->ThreadMain(); |
| 52 return NULL; |
| 53 } |
| 54 |
| 55 bool CreateThread(size_t stack_size, bool joinable, |
| 56 PlatformThread::Delegate* delegate, |
| 57 PlatformThreadHandle* thread_handle) { |
| 58 #if defined(OS_MACOSX) |
| 59 base::InitThreading(); |
| 60 #endif // OS_MACOSX |
| 61 |
| 62 bool success = false; |
| 63 pthread_attr_t attributes; |
| 64 pthread_attr_init(&attributes); |
| 65 |
| 66 // Pthreads are joinable by default, so only specify the detached attribute if |
| 67 // the thread should be non-joinable. |
| 68 if (!joinable) { |
| 69 pthread_attr_setdetachstate(&attributes, PTHREAD_CREATE_DETACHED); |
| 70 } |
| 71 |
| 72 #if defined(OS_MACOSX) |
| 73 // The Mac OS X default for a pthread stack size is 512kB. |
| 74 // Libc-594.1.4/pthreads/pthread.c's pthread_attr_init uses |
| 75 // DEFAULT_STACK_SIZE for this purpose. |
| 76 // |
| 77 // 512kB isn't quite generous enough for some deeply recursive threads that |
| 78 // otherwise request the default stack size by specifying 0. Here, adopt |
| 79 // glibc's behavior as on Linux, which is to use the current stack size |
| 80 // limit (ulimit -s) as the default stack size. See |
| 81 // glibc-2.11.1/nptl/nptl-init.c's __pthread_initialize_minimal_internal. To |
| 82 // avoid setting the limit below the Mac OS X default or the minimum usable |
| 83 // stack size, these values are also considered. If any of these values |
| 84 // can't be determined, or if stack size is unlimited (ulimit -s unlimited), |
| 85 // stack_size is left at 0 to get the system default. |
| 86 // |
| 87 // Mac OS X normally only applies ulimit -s to the main thread stack. On |
| 88 // contemporary OS X and Linux systems alike, this value is generally 8MB |
| 89 // or in that neighborhood. |
| 90 if (stack_size == 0) { |
| 91 size_t default_stack_size; |
| 92 struct rlimit stack_rlimit; |
| 93 if (pthread_attr_getstacksize(&attributes, &default_stack_size) == 0 && |
| 94 getrlimit(RLIMIT_STACK, &stack_rlimit) == 0 && |
| 95 stack_rlimit.rlim_cur != RLIM_INFINITY) { |
| 96 stack_size = std::max(std::max(default_stack_size, |
| 97 static_cast<size_t>(PTHREAD_STACK_MIN)), |
| 98 static_cast<size_t>(stack_rlimit.rlim_cur)); |
| 99 } |
| 100 } |
| 101 #endif // OS_MACOSX |
| 102 |
| 103 if (stack_size > 0) |
| 104 pthread_attr_setstacksize(&attributes, stack_size); |
| 105 |
| 106 ThreadParams* params = new ThreadParams; |
| 107 params->delegate = delegate; |
| 108 params->joinable = joinable; |
| 109 success = !pthread_create(thread_handle, &attributes, ThreadFunc, params); |
| 110 |
| 111 pthread_attr_destroy(&attributes); |
| 112 if (!success) |
| 113 delete params; |
| 114 return success; |
| 115 } |
| 116 |
| 117 } // namespace |
| 118 |
| 119 // static |
| 120 PlatformThreadId PlatformThread::CurrentId() { |
| 121 // Pthreads doesn't have the concept of a thread ID, so we have to reach down |
| 122 // into the kernel. |
| 123 #if defined(OS_MACOSX) |
| 124 return mach_thread_self(); |
| 125 #elif defined(OS_LINUX) |
| 126 return syscall(__NR_gettid); |
| 127 #elif defined(OS_FREEBSD) |
| 128 // TODO(BSD): find a better thread ID |
| 129 return reinterpret_cast<int64>(pthread_self()); |
| 130 #elif defined(OS_NACL) |
| 131 return pthread_self(); |
| 132 #endif |
| 133 } |
| 134 |
| 135 // static |
| 136 void PlatformThread::YieldCurrentThread() { |
| 137 sched_yield(); |
| 138 } |
| 139 |
| 140 // static |
| 141 void PlatformThread::Sleep(int duration_ms) { |
| 142 struct timespec sleep_time, remaining; |
| 143 |
| 144 // Contains the portion of duration_ms >= 1 sec. |
| 145 sleep_time.tv_sec = duration_ms / 1000; |
| 146 duration_ms -= sleep_time.tv_sec * 1000; |
| 147 |
| 148 // Contains the portion of duration_ms < 1 sec. |
| 149 sleep_time.tv_nsec = duration_ms * 1000 * 1000; // nanoseconds. |
| 150 |
| 151 while (nanosleep(&sleep_time, &remaining) == -1 && errno == EINTR) |
| 152 sleep_time = remaining; |
| 153 } |
| 154 |
| 155 // Linux SetName is currently disabled, as we need to distinguish between |
| 156 // helper threads (where it's ok to make this call) and the main thread |
| 157 // (where making this call renames our process, causing tools like killall |
| 158 // to stop working). |
| 159 #if 0 && defined(OS_LINUX) |
| 160 // static |
| 161 void PlatformThread::SetName(const char* name) { |
| 162 // http://0pointer.de/blog/projects/name-your-threads.html |
| 163 |
| 164 // glibc recently added support for pthread_setname_np, but it's not |
| 165 // commonly available yet. So test for it at runtime. |
| 166 int (*dynamic_pthread_setname_np)(pthread_t, const char*); |
| 167 *reinterpret_cast<void**>(&dynamic_pthread_setname_np) = |
| 168 dlsym(RTLD_DEFAULT, "pthread_setname_np"); |
| 169 |
| 170 if (dynamic_pthread_setname_np) { |
| 171 // This limit comes from glibc, which gets it from the kernel |
| 172 // (TASK_COMM_LEN). |
| 173 const int kMaxNameLength = 15; |
| 174 std::string shortened_name = std::string(name).substr(0, kMaxNameLength); |
| 175 int err = dynamic_pthread_setname_np(pthread_self(), |
| 176 shortened_name.c_str()); |
| 177 if (err < 0) |
| 178 LOG(ERROR) << "pthread_setname_np: " << safe_strerror(err); |
| 179 } else { |
| 180 // Implementing this function without glibc is simple enough. (We |
| 181 // don't do the name length clipping as above because it will be |
| 182 // truncated by the callee (see TASK_COMM_LEN above).) |
| 183 int err = prctl(PR_SET_NAME, name); |
| 184 if (err < 0) |
| 185 PLOG(ERROR) << "prctl(PR_SET_NAME)"; |
| 186 } |
| 187 } |
| 188 #elif defined(OS_MACOSX) |
| 189 // Mac is implemented in platform_thread_mac.mm. |
| 190 #else |
| 191 // static |
| 192 void PlatformThread::SetName(const char* /*name*/) { |
| 193 // Leave it unimplemented. |
| 194 |
| 195 // (This should be relatively simple to implement for the BSDs; I |
| 196 // just don't have one handy to test the code on.) |
| 197 } |
| 198 #endif // defined(OS_LINUX) |
| 199 |
| 200 // static |
| 201 bool PlatformThread::Create(size_t stack_size, Delegate* delegate, |
| 202 PlatformThreadHandle* thread_handle) { |
| 203 return CreateThread(stack_size, true /* joinable thread */, |
| 204 delegate, thread_handle); |
| 205 } |
| 206 |
| 207 // static |
| 208 bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) { |
| 209 PlatformThreadHandle unused; |
| 210 |
| 211 bool result = CreateThread(stack_size, false /* non-joinable thread */, |
| 212 delegate, &unused); |
| 213 return result; |
| 214 } |
| 215 |
| 216 // static |
| 217 void PlatformThread::Join(PlatformThreadHandle thread_handle) { |
| 218 // Joining another thread may block the current thread for a long time, since |
| 219 // the thread referred to by |thread_handle| may still be running long-lived / |
| 220 // blocking tasks. |
| 221 base::ThreadRestrictions::AssertIOAllowed(); |
| 222 pthread_join(thread_handle, NULL); |
| 223 } |
| 224 |
| 225 } // namespace base |
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