1 // posix-threads.cc - interface between libjava and POSIX threads.
3 /* Copyright (C) 1998, 1999, 2000, 2001, 2004 Free Software Foundation
5 This file is part of libgcj.
7 This software is copyrighted work licensed under the terms of the
8 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
12 // * Document signal handling limitations
16 // If we're using the Boehm GC, then we need to override some of the
17 // thread primitives. This is fairly gross.
20 #endif /* HAVE_BOEHM_GC */
28 #include <unistd.h> // To test for _POSIX_THREAD_PRIORITY_SCHEDULING
33 #include <java/lang/Thread.h>
34 #include <java/lang/System.h>
35 #include <java/lang/Long.h>
36 #include <java/lang/OutOfMemoryError.h>
37 #include <java/lang/InternalError.h>
39 // This is used to implement thread startup.
42 _Jv_ThreadStartFunc *method;
46 // This is the key used to map from the POSIX thread value back to the
47 // Java object representing the thread. The key is global to all
48 // threads, so it is ok to make it a global here.
49 pthread_key_t _Jv_ThreadKey;
51 // This is the key used to map from the POSIX thread value back to the
52 // _Jv_Thread_t* representing the thread.
53 pthread_key_t _Jv_ThreadDataKey;
55 // We keep a count of all non-daemon threads which are running. When
56 // this reaches zero, _Jv_ThreadWait returns.
57 static pthread_mutex_t daemon_mutex;
58 static pthread_cond_t daemon_cond;
59 static int non_daemon_count;
61 // The signal to use when interrupting a thread.
62 #if defined(LINUX_THREADS) || defined(FREEBSD_THREADS)
63 // LinuxThreads (prior to glibc 2.1) usurps both SIGUSR1 and SIGUSR2.
64 // GC on FreeBSD uses both SIGUSR1 and SIGUSR2.
66 #else /* LINUX_THREADS */
68 #endif /* LINUX_THREADS */
71 // These are the flags that can appear in _Jv_Thread_t.
75 #define FLAG_START 0x01
77 #define FLAG_DAEMON 0x02
81 // Wait for the condition variable "CV" to be notified.
83 // 0: the condition was notified, or the timeout expired.
84 // _JV_NOT_OWNER: the thread does not own the mutex "MU".
85 // _JV_INTERRUPTED: the thread was interrupted. Its interrupted flag is set.
87 _Jv_CondWait (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu,
88 jlong millis, jint nanos)
90 pthread_t self = pthread_self();
91 if (mu->owner != self)
96 if (millis > 0 || nanos > 0)
98 // Calculate the abstime corresponding to the timeout.
99 // Everything is in milliseconds.
101 // We use `unsigned long long' rather than jlong because our
102 // caller may pass up to Long.MAX_VALUE millis. This would
103 // overflow the range of a jlong when added to the current time.
105 unsigned long long startTime
106 = (unsigned long long)java::lang::System::currentTimeMillis();
107 unsigned long long m = (unsigned long long)millis + startTime;
108 unsigned long long seconds = m / 1000;
111 if (ts.tv_sec < 0 || (unsigned long long)ts.tv_sec != seconds)
113 // We treat a timeout that won't fit into a struct timespec
114 // as a wait forever.
120 ts.tv_nsec = m * 1000000 + (unsigned long long)nanos;
124 _Jv_Thread_t *current = _Jv_ThreadCurrentData ();
125 java::lang::Thread *current_obj = _Jv_ThreadCurrent ();
127 pthread_mutex_lock (¤t->wait_mutex);
129 // Now that we hold the wait mutex, check if this thread has been
130 // interrupted already.
131 if (current_obj->interrupt_flag)
133 pthread_mutex_unlock (¤t->wait_mutex);
134 return _JV_INTERRUPTED;
137 // Add this thread to the cv's wait set.
138 current->next = NULL;
140 if (cv->first == NULL)
143 for (_Jv_Thread_t *t = cv->first;; t = t->next)
152 // Record the current lock depth, so it can be restored when we re-aquire it.
153 int count = mu->count;
155 // Release the monitor mutex.
158 pthread_mutex_unlock (&mu->mutex);
161 bool done_sleeping = false;
163 while (! done_sleeping)
165 if (millis == 0 && nanos == 0)
166 r = pthread_cond_wait (¤t->wait_cond, ¤t->wait_mutex);
168 r = pthread_cond_timedwait (¤t->wait_cond, ¤t->wait_mutex,
171 // In older glibc's (prior to 2.1.3), the cond_wait functions may
172 // spuriously wake up on a signal. Catch that here.
174 done_sleeping = true;
177 // Check for an interrupt *before* releasing the wait mutex.
178 jboolean interrupted = current_obj->interrupt_flag;
180 pthread_mutex_unlock (¤t->wait_mutex);
182 // Reaquire the monitor mutex, and restore the lock count.
183 pthread_mutex_lock (&mu->mutex);
187 // If we were interrupted, or if a timeout occurred, remove ourself from
188 // the cv wait list now. (If we were notified normally, notify() will have
189 // already taken care of this)
190 if (r == ETIMEDOUT || interrupted)
192 _Jv_Thread_t *prev = NULL;
193 for (_Jv_Thread_t *t = cv->first; t != NULL; t = t->next)
198 prev->next = t->next;
207 return _JV_INTERRUPTED;
214 _Jv_CondNotify (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu)
216 if (_Jv_MutexCheckMonitor (mu))
217 return _JV_NOT_OWNER;
219 _Jv_Thread_t *target;
220 _Jv_Thread_t *prev = NULL;
222 for (target = cv->first; target != NULL; target = target->next)
224 pthread_mutex_lock (&target->wait_mutex);
226 if (target->thread_obj->interrupt_flag)
228 // Don't notify a thread that has already been interrupted.
229 pthread_mutex_unlock (&target->wait_mutex);
234 pthread_cond_signal (&target->wait_cond);
235 pthread_mutex_unlock (&target->wait_mutex);
237 // Two concurrent notify() calls must not be delivered to the same
238 // thread, so remove the target thread from the cv wait list now.
240 cv->first = target->next;
242 prev->next = target->next;
253 _Jv_CondNotifyAll (_Jv_ConditionVariable_t *cv, _Jv_Mutex_t *mu)
255 if (_Jv_MutexCheckMonitor (mu))
256 return _JV_NOT_OWNER;
258 _Jv_Thread_t *target;
259 _Jv_Thread_t *prev = NULL;
261 for (target = cv->first; target != NULL; target = target->next)
263 pthread_mutex_lock (&target->wait_mutex);
264 pthread_cond_signal (&target->wait_cond);
265 pthread_mutex_unlock (&target->wait_mutex);
280 _Jv_ThreadInterrupt (_Jv_Thread_t *data)
282 pthread_mutex_lock (&data->wait_mutex);
284 // Set the thread's interrupted flag *after* aquiring its wait_mutex. This
285 // ensures that there are no races with the interrupt flag being set after
286 // the waiting thread checks it and before pthread_cond_wait is entered.
287 data->thread_obj->interrupt_flag = true;
289 // Interrupt blocking system calls using a signal.
290 pthread_kill (data->thread, INTR);
292 pthread_cond_signal (&data->wait_cond);
294 pthread_mutex_unlock (&data->wait_mutex);
308 sigaddset (&mask, SIGCHLD);
309 int c = pthread_sigmask (SIG_BLOCK, &mask, NULL);
311 JvFail (strerror (c));
315 _Jv_InitThreads (void)
317 pthread_key_create (&_Jv_ThreadKey, NULL);
318 pthread_key_create (&_Jv_ThreadDataKey, NULL);
319 pthread_mutex_init (&daemon_mutex, NULL);
320 pthread_cond_init (&daemon_cond, 0);
321 non_daemon_count = 0;
323 // Arrange for the interrupt signal to interrupt system calls.
324 struct sigaction act;
325 act.sa_handler = handle_intr;
326 sigemptyset (&act.sa_mask);
328 sigaction (INTR, &act, NULL);
330 // Block SIGCHLD here to ensure that any non-Java threads inherit the new
334 // Check/set the thread stack size.
335 size_t min_ss = 32 * 1024;
337 if (sizeof (void *) == 8)
338 // Bigger default on 64-bit systems.
341 #ifdef PTHREAD_STACK_MIN
342 if (min_ss < PTHREAD_STACK_MIN)
343 min_ss = PTHREAD_STACK_MIN;
346 if (gcj::stack_size > 0 && gcj::stack_size < min_ss)
347 gcj::stack_size = min_ss;
351 _Jv_ThreadInitData (java::lang::Thread *obj)
353 _Jv_Thread_t *data = (_Jv_Thread_t *) _Jv_Malloc (sizeof (_Jv_Thread_t));
355 data->thread_obj = obj;
357 pthread_mutex_init (&data->wait_mutex, NULL);
358 pthread_cond_init (&data->wait_cond, NULL);
364 _Jv_ThreadDestroyData (_Jv_Thread_t *data)
366 pthread_mutex_destroy (&data->wait_mutex);
367 pthread_cond_destroy (&data->wait_cond);
368 _Jv_Free ((void *)data);
372 _Jv_ThreadSetPriority (_Jv_Thread_t *data, jint prio)
374 #ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
375 if (data->flags & FLAG_START)
377 struct sched_param param;
379 param.sched_priority = prio;
380 pthread_setschedparam (data->thread, SCHED_OTHER, ¶m);
386 _Jv_ThreadRegister (_Jv_Thread_t *data)
388 pthread_setspecific (_Jv_ThreadKey, data->thread_obj);
389 pthread_setspecific (_Jv_ThreadDataKey, data);
391 // glibc 2.1.3 doesn't set the value of `thread' until after start_routine
392 // is called. Since it may need to be accessed from the new thread, work
393 // around the potential race here by explicitly setting it again.
394 data->thread = pthread_self ();
396 # ifdef SLOW_PTHREAD_SELF
397 // Clear all self cache slots that might be needed by this thread.
399 int low_index = SC_INDEX(&dummy) + SC_CLEAR_MIN;
400 int high_index = SC_INDEX(&dummy) + SC_CLEAR_MAX;
401 for (int i = low_index; i <= high_index; ++i)
403 int current_index = i;
404 if (current_index < 0)
405 current_index += SELF_CACHE_SIZE;
406 if (current_index >= SELF_CACHE_SIZE)
407 current_index -= SELF_CACHE_SIZE;
408 _Jv_self_cache[current_index].high_sp_bits = BAD_HIGH_SP_VALUE;
411 // Block SIGCHLD which is used in natPosixProcess.cc.
416 _Jv_ThreadUnRegister ()
418 pthread_setspecific (_Jv_ThreadKey, NULL);
419 pthread_setspecific (_Jv_ThreadDataKey, NULL);
422 // This function is called when a thread is started. We don't arrange
423 // to call the `run' method directly, because this function must
426 really_start (void *x)
428 struct starter *info = (struct starter *) x;
430 _Jv_ThreadRegister (info->data);
432 info->method (info->data->thread_obj);
434 if (! (info->data->flags & FLAG_DAEMON))
436 pthread_mutex_lock (&daemon_mutex);
438 if (! non_daemon_count)
439 pthread_cond_signal (&daemon_cond);
440 pthread_mutex_unlock (&daemon_mutex);
447 _Jv_ThreadStart (java::lang::Thread *thread, _Jv_Thread_t *data,
448 _Jv_ThreadStartFunc *meth)
450 struct sched_param param;
452 struct starter *info;
454 if (data->flags & FLAG_START)
456 data->flags |= FLAG_START;
458 // Block SIGCHLD which is used in natPosixProcess.cc.
459 // The current mask is inherited by the child thread.
462 param.sched_priority = thread->getPriority();
464 pthread_attr_init (&attr);
465 pthread_attr_setschedparam (&attr, ¶m);
466 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
468 // Set stack size if -Xss option was given.
469 if (gcj::stack_size > 0)
471 int e = pthread_attr_setstacksize (&attr, gcj::stack_size);
473 JvFail (strerror (e));
476 info = (struct starter *) _Jv_AllocBytes (sizeof (struct starter));
480 if (! thread->isDaemon())
482 pthread_mutex_lock (&daemon_mutex);
484 pthread_mutex_unlock (&daemon_mutex);
487 data->flags |= FLAG_DAEMON;
488 int r = pthread_create (&data->thread, &attr, really_start, (void *) info);
490 pthread_attr_destroy (&attr);
494 const char* msg = "Cannot create additional threads";
495 throw new java::lang::OutOfMemoryError (JvNewStringUTF (msg));
500 _Jv_ThreadWait (void)
502 pthread_mutex_lock (&daemon_mutex);
503 if (non_daemon_count)
504 pthread_cond_wait (&daemon_cond, &daemon_mutex);
505 pthread_mutex_unlock (&daemon_mutex);
508 #if defined(SLOW_PTHREAD_SELF)
510 #include "sysdep/locks.h"
512 // Support for pthread_self() lookup cache.
513 volatile self_cache_entry _Jv_self_cache[SELF_CACHE_SIZE];
516 _Jv_ThreadSelf_out_of_line(volatile self_cache_entry *sce, size_t high_sp_bits)
518 pthread_t self = pthread_self();
519 sce -> high_sp_bits = high_sp_bits;
525 #endif /* SLOW_PTHREAD_SELF */