ref: 52cacba37c6f3a125ef931afa4b9c2cdb7438fef
dir: /sys/src/cmd/python/Python/thread_atheos.h/
/* 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
}