thread_atheos.h 5.95 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
/* Threading for AtheOS.
   Based on thread_beos.h. */

#include <atheos/threads.h>
#include <atheos/semaphore.h>
#include <atheos/atomic.h>
#include <errno.h>
#include <string.h>

/* Missing decl from threads.h */
extern int exit_thread(int);


/* Undefine FASTLOCK to play with simple semaphores. */
#define FASTLOCK


#ifdef FASTLOCK

/* Use an atomic counter and a semaphore for maximum speed. */
typedef struct fastmutex {
	sem_id sem;
	atomic_t count;
} fastmutex_t;


static int fastmutex_create(const char *name, fastmutex_t * mutex);
static int fastmutex_destroy(fastmutex_t * mutex);
static int fastmutex_lock(fastmutex_t * mutex);
static int fastmutex_timedlock(fastmutex_t * mutex, bigtime_t timeout);
static int fastmutex_unlock(fastmutex_t * mutex);


static int fastmutex_create(const char *name, fastmutex_t * mutex)
{
	mutex->count = 0;
	mutex->sem = create_semaphore(name, 0, 0);
	return (mutex->sem < 0) ? -1 : 0;
}


static int fastmutex_destroy(fastmutex_t * mutex)
{
	if (fastmutex_timedlock(mutex, 0) == 0 || errno == EWOULDBLOCK) {
		return delete_semaphore(mutex->sem);
	}
	return 0;
}


static int fastmutex_lock(fastmutex_t * mutex)
{
	atomic_t prev = atomic_add(&mutex->count, 1);
	if (prev > 0)
		return lock_semaphore(mutex->sem);
	return 0;
}


static int fastmutex_timedlock(fastmutex_t * mutex, bigtime_t timeout)
{
	atomic_t prev = atomic_add(&mutex->count, 1);
	if (prev > 0)
		return lock_semaphore_x(mutex->sem, 1, 0, timeout);
	return 0;
}


static int fastmutex_unlock(fastmutex_t * mutex)
{
	atomic_t prev = atomic_add(&mutex->count, -1);
	if (prev > 1)
		return unlock_semaphore(mutex->sem);
	return 0;
}


#endif				/* FASTLOCK */


/*
 * Initialization.
 *
 */
static void PyThread__init_thread(void)
{
	/* Do nothing. */
	return;
}


/*
 * Thread support.
 *
 */

static atomic_t thread_count = 0;

long PyThread_start_new_thread(void (*func) (void *), void *arg)
{
	status_t success = -1;
	thread_id tid;
	char name[OS_NAME_LENGTH];
	atomic_t this_thread;

	dprintf(("PyThread_start_new_thread called\n"));

	this_thread = atomic_add(&thread_count, 1);
	PyOS_snprintf(name, sizeof(name), "python thread (%d)", this_thread);

	tid = spawn_thread(name, func, NORMAL_PRIORITY, 0, arg);
	if (tid < 0) {
		dprintf(("PyThread_start_new_thread spawn_thread failed: %s\n", strerror(errno)));
	} else {
		success = resume_thread(tid);
		if (success < 0) {
			dprintf(("PyThread_start_new_thread resume_thread failed: %s\n", strerror(errno)));
		}
	}

	return (success < 0 ? -1 : tid);
}


long PyThread_get_thread_ident(void)
{
	return get_thread_id(NULL);
}


static void do_PyThread_exit_thread(int no_cleanup)
{
	dprintf(("PyThread_exit_thread called\n"));

	/* Thread-safe way to read a variable without a mutex: */
	if (atomic_add(&thread_count, 0) == 0) {
		/* No threads around, so exit main(). */
		if (no_cleanup)
			_exit(0);
		else
			exit(0);
	} else {
		/* We're a thread */
		exit_thread(0);
	}
}


void PyThread_exit_thread(void)
{
	do_PyThread_exit_thread(0);
}


void PyThread__exit_thread(void)
{
	do_PyThread_exit_thread(1);
}


#ifndef NO_EXIT_PROG
static void do_PyThread_exit_prog(int status, int no_cleanup)
{
	dprintf(("PyThread_exit_prog(%d) called\n", status));

	/* No need to do anything, the threads get torn down if main()exits. */
	if (no_cleanup)
		_exit(status);
	else
		exit(status);
}


void PyThread_exit_prog(int status)
{
	do_PyThread_exit_prog(status, 0);
}


void PyThread__exit_prog(int status)
{
	do_PyThread_exit_prog(status, 1);
}
#endif				/* NO_EXIT_PROG */


/*
 * Lock support.
 *
 */

static atomic_t lock_count = 0;

PyThread_type_lock PyThread_allocate_lock(void)
{
#ifdef FASTLOCK
	fastmutex_t *lock;
#else
	sem_id sema;
#endif
	char name[OS_NAME_LENGTH];
	atomic_t this_lock;

	dprintf(("PyThread_allocate_lock called\n"));

#ifdef FASTLOCK
	lock = (fastmutex_t *) malloc(sizeof(fastmutex_t));
	if (lock == NULL) {
		dprintf(("PyThread_allocate_lock failed: out of memory\n"));
		return (PyThread_type_lock) NULL;
	}
#endif
	this_lock = atomic_add(&lock_count, 1);
	PyOS_snprintf(name, sizeof(name), "python lock (%d)", this_lock);

#ifdef FASTLOCK
	if (fastmutex_create(name, lock) < 0) {
		dprintf(("PyThread_allocate_lock failed: %s\n",
			 strerror(errno)));
		free(lock);
		lock = NULL;
	}
	dprintf(("PyThread_allocate_lock()-> %p\n", lock));
	return (PyThread_type_lock) lock;
#else
	sema = create_semaphore(name, 1, 0);
	if (sema < 0) {
		dprintf(("PyThread_allocate_lock failed: %s\n",
			 strerror(errno)));
		sema = 0;
	}
	dprintf(("PyThread_allocate_lock()-> %p\n", sema));
	return (PyThread_type_lock) sema;
#endif
}


void PyThread_free_lock(PyThread_type_lock lock)
{
	dprintf(("PyThread_free_lock(%p) called\n", lock));

#ifdef FASTLOCK
	if (fastmutex_destroy((fastmutex_t *) lock) < 0) {
		dprintf(("PyThread_free_lock(%p) failed: %s\n", lock,
			 strerror(errno)));
	}
	free(lock);
#else
	if (delete_semaphore((sem_id) lock) < 0) {
		dprintf(("PyThread_free_lock(%p) failed: %s\n", lock,
			 strerror(errno)));
	}
#endif
}


int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
{
	int retval;

	dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock,
		 waitflag));

#ifdef FASTLOCK
	if (waitflag)
		retval = fastmutex_lock((fastmutex_t *) lock);
	else
		retval = fastmutex_timedlock((fastmutex_t *) lock, 0);
#else
	if (waitflag)
		retval = lock_semaphore((sem_id) lock);
	else
		retval = lock_semaphore_x((sem_id) lock, 1, 0, 0);
#endif
	if (retval < 0) {
		dprintf(("PyThread_acquire_lock(%p, %d) failed: %s\n",
			 lock, waitflag, strerror(errno)));
	}
	dprintf(("PyThread_acquire_lock(%p, %d)-> %d\n", lock, waitflag,
		 retval));
	return retval < 0 ? 0 : 1;
}


void PyThread_release_lock(PyThread_type_lock lock)
{
	dprintf(("PyThread_release_lock(%p) called\n", lock));

#ifdef FASTLOCK
	if (fastmutex_unlock((fastmutex_t *) lock) < 0) {
		dprintf(("PyThread_release_lock(%p) failed: %s\n", lock,
			 strerror(errno)));
	}
#else
	if (unlock_semaphore((sem_id) lock) < 0) {
		dprintf(("PyThread_release_lock(%p) failed: %s\n", lock,
			 strerror(errno)));
	}
#endif
}