static void
mutex_rescan_owned(pthread_t pthread, pthread_mutex_t mutex)
{
int active_prio, inherited_prio;
pthread_mutex_t m;
pthread_t pthread_next;
/*
* Start walking the mutexes the thread has taken since
* taking this mutex.
*/
if (mutex == NULL) {
/*
* A null mutex means start at the beginning of the owned
* mutex list.
*/
m = TAILQ_FIRST(&pthread->mutexq);
/* There is no inherited priority yet. */
inherited_prio = 0;
}
else {
/*
* The caller wants to start after a specific mutex. It
* is assumed that this mutex is a priority inheritence
* mutex and that its priority has been correctly
* calculated.
*/
m = TAILQ_NEXT(mutex, m_qe);
/* Start inheriting priority from the specified mutex. */
inherited_prio = mutex->m_prio;
}
active_prio = MAX(inherited_prio, pthread->base_priority);
while (m != NULL) {
/*
* We only want to deal with priority inheritence
* mutexes. This might be optimized by only placing
* priority inheritence mutexes into the owned mutex
* list, but it may prove to be useful having all
* owned mutexes in this list. Consider a thread
* exiting while holding mutexes...
*/
if (m->m_protocol == PTHREAD_PRIO_INHERIT) {
/*
* Fix the owners saved (inherited) priority to
* reflect the priority of the previous mutex.
*/
m->m_saved_prio = inherited_prio;
if ((pthread_next = TAILQ_FIRST(&m->m_queue)) != NULL)
/* Recalculate the priority of the mutex: */
m->m_prio = MAX(active_prio,
pthread_next->active_priority);
else
m->m_prio = active_prio;
/* Recalculate new inherited and active priorities: */
inherited_prio = m->m_prio;
active_prio = MAX(m->m_prio, pthread->base_priority);
}
/* Advance to the next mutex owned by this thread: */
m = TAILQ_NEXT(m, m_qe);
}
/*
* Fix the threads inherited priority and recalculate its
* active priority.
*/
pthread->inherited_priority = inherited_prio;
active_prio = MAX(inherited_prio, pthread->base_priority);
if (active_prio != pthread->active_priority) {
/*
* If this thread is in the priority queue, it must be
* removed and reinserted for its new priority.
*/
if (pthread->flags & PTHREAD_FLAGS_IN_PRIOQ) {
/*
* Remove the thread from the priority queue
* before changing its priority:
*/
PTHREAD_PRIOQ_REMOVE(pthread);
/*
* POSIX states that if the priority is being
* lowered, the thread must be inserted at the
* head of the queue for its priority if it owns
* any priority protection or inheritence mutexes.
*/
if ((active_prio < pthread->active_priority) &&
(pthread->priority_mutex_count > 0)) {
/* Set the new active priority. */
pthread->active_priority = active_prio;
PTHREAD_PRIOQ_INSERT_HEAD(pthread);
}
else {
/* Set the new active priority. */
pthread->active_priority = active_prio;
PTHREAD_PRIOQ_INSERT_TAIL(pthread);
}
}
else {
/* Set the new active priority. */
pthread->active_priority = active_prio;
}
}
}
int
_pthread_create(pthread_t *thread, const pthread_attr_t *attr,
void *(*start_routine) (void *), void *arg)
{
struct pthread *curthread = _get_curthread();
struct itimerval itimer;
int f_gc = 0;
int ret = 0;
pthread_t gc_thread;
pthread_t new_thread;
pthread_attr_t pattr;
void *stack;
if (thread == NULL)
return (EINVAL);
/*
* Locking functions in libc are required when there are
* threads other than the initial thread.
*/
__isthreaded = 1;
/* Allocate memory for the thread structure: */
if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
} else {
/* Check if default thread attributes are required: */
if (attr == NULL || *attr == NULL) {
/* Use the default thread attributes: */
pattr = &pthread_attr_default;
} else {
pattr = *attr;
}
/* Check if a stack was specified in the thread attributes: */
if ((stack = pattr->stackaddr_attr) != NULL) {
}
/* Allocate memory for a default-size stack: */
else if (pattr->stacksize_attr == PTHREAD_STACK_DEFAULT) {
struct stack *spare_stack;
/* Allocate or re-use a default-size stack. */
/*
* Use the garbage collector mutex for synchronization
* of the spare stack list.
*/
if (pthread_mutex_lock(&_gc_mutex) != 0)
PANIC("Cannot lock gc mutex");
if ((spare_stack = SLIST_FIRST(&_stackq)) != NULL) {
/* Use the spare stack. */
SLIST_REMOVE_HEAD(&_stackq, qe);
/* Unlock the garbage collector mutex. */
if (pthread_mutex_unlock(&_gc_mutex) != 0)
PANIC("Cannot unlock gc mutex");
stack = sizeof(struct stack)
+ (void *) spare_stack
- PTHREAD_STACK_DEFAULT;
} else {
/* Allocate a new stack. */
stack = _next_stack + PTHREAD_STACK_GUARD;
/*
* Even if stack allocation fails, we don't want
* to try to use this location again, so
* unconditionally decrement _next_stack. Under
* normal operating conditions, the most likely
* reason for an mmap() error is a stack
* overflow of the adjacent thread stack.
*/
_next_stack -= (PTHREAD_STACK_DEFAULT
+ PTHREAD_STACK_GUARD);
/* Unlock the garbage collector mutex. */
if (pthread_mutex_unlock(&_gc_mutex) != 0)
PANIC("Cannot unlock gc mutex");
/* Stack: */
if (mmap(stack, PTHREAD_STACK_DEFAULT,
PROT_READ | PROT_WRITE, MAP_STACK,
-1, 0) == MAP_FAILED) {
ret = EAGAIN;
free(new_thread);
}
}
}
/*
* The user wants a stack of a particular size. Lets hope they
* really know what they want, and simply malloc the stack.
*/
else if ((stack = (void *) malloc(pattr->stacksize_attr))
== NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
free(new_thread);
}
/* Check for errors: */
if (ret != 0) {
} else {
/* Initialise the thread structure: */
memset(new_thread, 0, sizeof(struct pthread));
new_thread->tcb = _libc_allocate_tls();
if (new_thread->tcb == NULL)
PANIC("Cannot allocate TLS and TCB");
new_thread->slice_usec = -1;
new_thread->stack = stack;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
PTHREAD_CANCEL_DEFERRED;
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
new_thread->magic = PTHREAD_MAGIC;
/* Initialise the thread for signals: */
new_thread->sigmask = curthread->sigmask;
new_thread->sigmask_seqno = 0;
/* Initialize the signal frame: */
new_thread->curframe = NULL;
/* Initialise the jump buffer: */
_setjmp(new_thread->ctx.jb);
/*
* Set up new stack frame so that it looks like it
* returned from a longjmp() to the beginning of
* _thread_start().
*/
SET_RETURN_ADDR_JB(new_thread->ctx.jb, _thread_start);
/* The stack starts high and builds down: */
SET_STACK_JB(new_thread->ctx.jb,
(long)new_thread->stack + pattr->stacksize_attr
- sizeof(double));
/* Copy the thread attributes: */
memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
/*
* Check if this thread is to inherit the scheduling
* attributes from its parent:
*/
if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) {
/* Copy the scheduling attributes: */
new_thread->base_priority =
curthread->base_priority &
~PTHREAD_SIGNAL_PRIORITY;
new_thread->attr.prio =
curthread->base_priority &
~PTHREAD_SIGNAL_PRIORITY;
new_thread->attr.sched_policy =
curthread->attr.sched_policy;
} else {
/*
* Use just the thread priority, leaving the
* other scheduling attributes as their
* default values:
*/
new_thread->base_priority =
new_thread->attr.prio;
}
new_thread->active_priority = new_thread->base_priority;
new_thread->inherited_priority = 0;
/* Initialize joiner to NULL (no joiner): */
new_thread->joiner = NULL;
/* Initialize the mutex queue: */
TAILQ_INIT(&new_thread->mutexq);
/* Initialise hooks in the thread structure: */
new_thread->specific_data = NULL;
new_thread->cleanup = NULL;
new_thread->flags = 0;
new_thread->poll_data.nfds = 0;
new_thread->poll_data.fds = NULL;
new_thread->continuation = NULL;
/*
* Defer signals to protect the scheduling queues
* from access by the signal handler:
*/
_thread_kern_sig_defer();
/*
* Initialise the unique id which GDB uses to
* track threads.
*/
new_thread->uniqueid = next_uniqueid++;
/*
* Check if the garbage collector thread
* needs to be started.
*/
f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial);
/* Add the thread to the linked list of all threads: */
TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle);
if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) {
new_thread->flags |= PTHREAD_FLAGS_SUSPENDED;
new_thread->state = PS_SUSPENDED;
} else {
new_thread->state = PS_RUNNING;
PTHREAD_PRIOQ_INSERT_TAIL(new_thread);
}
/*
* Undefer and handle pending signals, yielding
* if necessary.
*/
_thread_kern_sig_undefer();
/* Return a pointer to the thread structure: */
(*thread) = new_thread;
if (f_gc != 0) {
/* Install the scheduling timer: */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = _clock_res_usec;
itimer.it_value = itimer.it_interval;
if (setitimer(_ITIMER_SCHED_TIMER, &itimer,
NULL) != 0)
PANIC("Cannot set interval timer");
}
/* Schedule the new user thread: */
_thread_kern_sched(NULL);
/*
* Start a garbage collector thread
* if necessary.
*/
if (f_gc && pthread_create(&gc_thread,NULL,
_thread_gc,NULL) != 0)
PANIC("Can't create gc thread");
}
}
/* Return the status: */
return (ret);
}
int
_pthread_create(pthread_t *thread, const pthread_attr_t *attr,
void *(*start_routine) (void *), void *arg)
{
struct pthread *curthread = _get_curthread();
struct itimerval itimer;
int f_gc = 0;
int ret = 0;
pthread_t gc_thread;
pthread_t new_thread;
pthread_attr_t pattr;
void *stack;
#if !defined(__ia64__)
u_long stackp;
#endif
if (thread == NULL)
return(EINVAL);
/*
* Locking functions in libc are required when there are
* threads other than the initial thread.
*/
__isthreaded = 1;
/* Allocate memory for the thread structure: */
if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
} else {
/* Check if default thread attributes are required: */
if (attr == NULL || *attr == NULL) {
/* Use the default thread attributes: */
pattr = &_pthread_attr_default;
} else {
pattr = *attr;
}
/* Check if a stack was specified in the thread attributes: */
if ((stack = pattr->stackaddr_attr) != NULL) {
}
/* Allocate a stack: */
else {
stack = _thread_stack_alloc(pattr->stacksize_attr,
pattr->guardsize_attr);
if (stack == NULL) {
ret = EAGAIN;
free(new_thread);
}
}
/* Check for errors: */
if (ret != 0) {
} else {
/* Initialise the thread structure: */
memset(new_thread, 0, sizeof(struct pthread));
new_thread->slice_usec = -1;
new_thread->stack = stack;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
PTHREAD_CANCEL_DEFERRED;
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
new_thread->magic = PTHREAD_MAGIC;
/* Initialise the thread for signals: */
new_thread->sigmask = curthread->sigmask;
new_thread->sigmask_seqno = 0;
/* Initialize the signal frame: */
new_thread->curframe = NULL;
/* Initialise the jump buffer: */
_setjmp(new_thread->ctx.jb);
/*
* Set up new stack frame so that it looks like it
* returned from a longjmp() to the beginning of
* _thread_start().
*/
SET_RETURN_ADDR_JB(new_thread->ctx.jb, _thread_start);
#if !defined(__ia64__)
stackp = (long)new_thread->stack + pattr->stacksize_attr - sizeof(double);
#if defined(__amd64__)
stackp &= ~0xFUL;
#endif
/* The stack starts high and builds down: */
SET_STACK_JB(new_thread->ctx.jb, stackp);
#else
SET_STACK_JB(new_thread->ctx.jb,
(long)new_thread->stack, pattr->stacksize_attr);
#endif
/* Copy the thread attributes: */
memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
/*
* Check if this thread is to inherit the scheduling
* attributes from its parent:
*/
if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) {
/* Copy the scheduling attributes: */
new_thread->base_priority =
curthread->base_priority &
~PTHREAD_SIGNAL_PRIORITY;
new_thread->attr.prio =
curthread->base_priority &
~PTHREAD_SIGNAL_PRIORITY;
new_thread->attr.sched_policy =
curthread->attr.sched_policy;
} else {
/*
* Use just the thread priority, leaving the
* other scheduling attributes as their
* default values:
*/
new_thread->base_priority =
new_thread->attr.prio;
}
new_thread->active_priority = new_thread->base_priority;
new_thread->inherited_priority = 0;
/* Initialize joiner to NULL (no joiner): */
new_thread->joiner = NULL;
/* Initialize the mutex queue: */
TAILQ_INIT(&new_thread->mutexq);
/* Initialise hooks in the thread structure: */
new_thread->specific = NULL;
new_thread->cleanup = NULL;
new_thread->flags = 0;
new_thread->poll_data.nfds = 0;
new_thread->poll_data.fds = NULL;
new_thread->continuation = NULL;
/*
* Defer signals to protect the scheduling queues
* from access by the signal handler:
*/
_thread_kern_sig_defer();
/*
* Initialise the unique id which GDB uses to
* track threads.
*/
new_thread->uniqueid = next_uniqueid++;
/*
* Check if the garbage collector thread
* needs to be started.
*/
f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial);
/* Add the thread to the linked list of all threads: */
TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle);
if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) {
new_thread->flags |= PTHREAD_FLAGS_SUSPENDED;
new_thread->state = PS_SUSPENDED;
} else {
new_thread->state = PS_RUNNING;
PTHREAD_PRIOQ_INSERT_TAIL(new_thread);
}
/*
* Undefer and handle pending signals, yielding
* if necessary.
*/
_thread_kern_sig_undefer();
/* Return a pointer to the thread structure: */
(*thread) = new_thread;
if (f_gc != 0) {
/* Install the scheduling timer: */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = _clock_res_usec;
itimer.it_value = itimer.it_interval;
if (setitimer(_ITIMER_SCHED_TIMER, &itimer,
NULL) != 0)
PANIC("Cannot set interval timer");
}
/* Schedule the new user thread: */
_thread_kern_sched(NULL);
/*
* Start a garbage collector thread
* if necessary.
*/
if (f_gc && _pthread_create(&gc_thread, NULL,
_thread_gc, NULL) != 0)
PANIC("Can't create gc thread");
}
}
/* Return the status: */
return (ret);
}
