-/* $Id$ */
-
-/* Copyright (c) 2007 Arnaud Legrand, Bruno Donnassolo.
- All rights reserved. */
+/* Copyright (c) 2007, 2008, 2009, 2010. The SimGrid Team.
+ * All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
/** @brief Initialize a semaphore */
smx_sem_t SIMIX_sem_init(int capacity) {
smx_sem_t sem = xbt_new0(s_smx_sem_t, 1);
- s_smx_process_t p;
- sem->sleeping = xbt_swag_new(xbt_swag_offset(p, synchro_hookup));
+ sem->sleeping = xbt_fifo_new();
sem->actions = xbt_fifo_new();
sem->capacity = capacity;
return sem;
}
/** @brief Destroys a semaphore */
void SIMIX_sem_destroy(smx_sem_t sem) {
+ smx_action_t action = NULL;
DEBUG1("Destroy semaphore %p", sem);
if (sem == NULL)
return;
- smx_action_t action = NULL;
-
- xbt_assert0(xbt_swag_size(sem->sleeping) == 0,
+ xbt_assert0(xbt_fifo_size(sem->sleeping) == 0,
"Cannot destroy semaphore since someone is still using it");
- xbt_swag_free(sem->sleeping);
+ xbt_fifo_free(sem->sleeping);
DEBUG1("%d actions registered", xbt_fifo_size(sem->actions));
while((action=xbt_fifo_pop(sem->actions)))
* If no one was blocked, the semaphore capacity is increased by 1.
* */
void SIMIX_sem_release(smx_sem_t sem) {
- DEBUG1("Sem release semaphore %p", sem);
- if (xbt_swag_size(sem->sleeping) >= 1) {
- smx_process_t proc = xbt_swag_extract(sem->sleeping);
- xbt_swag_insert(proc, simix_global->process_to_run);
- } else if (sem->capacity != SMX_SEM_NOLIMIT) {
+ smx_process_t proc;
+
+ if (sem->capacity != SMX_SEM_NOLIMIT) {
sem->capacity++;
}
+ DEBUG1("Sem release semaphore %p", sem);
+ if ((proc = xbt_fifo_shift(sem->sleeping)) != NULL) {
+ xbt_swag_insert(proc, simix_global->process_to_run);
+ }
}
/** @brief make sure the semaphore will never be blocking again
*
* There is no way to reset the semaphore to a more regular state afterward.
* */
void SIMIX_sem_release_forever(smx_sem_t sem) {
- smx_process_t proc = NULL;
- smx_process_t proc_next = NULL;
+ smx_process_t proc;
+ sem->capacity = SMX_SEM_NOLIMIT;
DEBUG1("Broadcast semaphore %p", sem);
- xbt_swag_foreach_safe(proc, proc_next, sem->sleeping) {
- xbt_swag_remove(proc, sem->sleeping);
+ while ((proc = xbt_fifo_shift(sem->sleeping)) != NULL) {
xbt_swag_insert(proc, simix_global->process_to_run);
}
}
/* process status */
self->sem = sem;
- xbt_swag_insert(self, sem->sleeping);
+ xbt_fifo_push (sem->sleeping, self);
SIMIX_process_yield();
self->sem = NULL;
while (self->suspended)
/** @brief Returns true if acquiring this semaphore would block */
XBT_INLINE int SIMIX_sem_would_block(smx_sem_t sem) {
- return (sem->capacity>0);
+ return (sem->capacity<=0);
+}
+
+/** @brief Returns the current capacity of the semaphore
+ *
+ * If it's negative, that's the amount of processes locked on the semaphore
+ */
+int SIMIX_sem_get_capacity(smx_sem_t sem){
+ return sem->capacity;
}
/**
* until someone call SIMIX_sem_release() on this semaphore
*/
void SIMIX_sem_acquire(smx_sem_t sem) {
- smx_action_t act_sleep;
-
- DEBUG1("Wait semaphore %p", sem);
-
- if (sem->capacity == SMX_SEM_NOLIMIT)
- return; /* don't even decrease it if wide open */
-
- /* If capacity sufficient, decrease it */
- if (sem->capacity>0) {
- sem->capacity--;
- return;
- }
-
- /* Always create an action null in case there is a host failure */
- act_sleep = SIMIX_action_sleep(SIMIX_host_self(), -1);
- SIMIX_action_set_name(act_sleep,bprintf("Locked in semaphore %p", sem));
- SIMIX_process_self()->waiting_action = act_sleep;
- SIMIX_register_action_to_semaphore(act_sleep, sem);
- SIMIX_sem_block_onto(sem);
- SIMIX_process_self()->waiting_action = NULL;
- SIMIX_unregister_action_to_semaphore(act_sleep, sem);
- SIMIX_action_destroy(act_sleep);
- DEBUG1("End of Wait on semaphore %p", sem);
+ SIMIX_sem_acquire_timeout (sem, -1);
}
+
/**
* \brief Tries to acquire a semaphore before a timeout
*
void SIMIX_sem_acquire_timeout(smx_sem_t sem, double max_duration) {
smx_action_t act_sleep;
- DEBUG2("Timed wait semaphore %p (timeout:%f)", sem,max_duration);
+ DEBUG2("Wait semaphore %p (timeout:%f)", sem, max_duration);
- if (sem->capacity == SMX_SEM_NOLIMIT)
+ if (sem->capacity == SMX_SEM_NOLIMIT) {
+ DEBUG1("semaphore %p wide open", sem);
return; /* don't even decrease it if wide open */
+ }
/* If capacity sufficient, decrease it */
if (sem->capacity>0) {
+ DEBUG1("semaphore %p has enough capacity", sem);
sem->capacity--;
return;
}
- if (max_duration >= 0) {
- act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
- SIMIX_action_set_name(act_sleep,bprintf("Timed wait semaphore %p (max_duration:%f)", sem,max_duration));
- SIMIX_register_action_to_semaphore(act_sleep, sem);
- SIMIX_process_self()->waiting_action = act_sleep;
- SIMIX_sem_block_onto(sem);
- SIMIX_process_self()->waiting_action = NULL;
- SIMIX_unregister_action_to_semaphore(act_sleep, sem);
- if (SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
- SIMIX_action_destroy(act_sleep);
- THROW1(timeout_error, 0, "Semaphore acquire timeouted after %f",max_duration);
- } else {
- SIMIX_action_destroy(act_sleep);
+ /* Always create an action null in case there is a host failure */
+ act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
+ SIMIX_action_set_name(act_sleep,bprintf("Locked in semaphore %p (max_duration:%f)", sem, max_duration));
+ SIMIX_process_self()->waiting_action = act_sleep;
+ SIMIX_register_action_to_semaphore(act_sleep, sem);
+ SIMIX_sem_block_onto(sem);
+ SIMIX_process_self()->waiting_action = NULL;
+ SIMIX_unregister_action_to_semaphore(act_sleep, sem);
+ if (max_duration >= 0 && SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
+ SIMIX_action_destroy(act_sleep);
+ THROW1(timeout_error, 0, "Semaphore acquire timeouted after %f",max_duration);
+ } else {
+ if (sem->capacity != SMX_SEM_NOLIMIT) {
+ /* Take the released token */
+ sem->capacity--;
}
-
- } else
- SIMIX_sem_acquire(sem);
+ SIMIX_action_destroy(act_sleep);
+ }
+ DEBUG1("End of Wait on semaphore %p", sem);
}
/**
* \brief Blocks on a set of semaphore
xbt_assert0(xbt_dynar_length(sems),
"I refuse to commit sucide by locking on an **empty** set of semaphores!!");
- DEBUG1("Wait on semaphore set %p", sems);
+ DEBUG2("Wait on semaphore set %p (containing %ld semaphores)", sems,xbt_dynar_length(sems));
xbt_dynar_foreach(sems,counter,sem) {
- if (!SIMIX_sem_would_block(sem))
+ if (!SIMIX_sem_would_block(sem)) {
+ DEBUG1("Semaphore %p wouldn't block; get it without waiting",sem);
SIMIX_sem_acquire(sem);
- return counter;
+ return counter;
+ }
}
/* Always create an action null in case there is a host failure */
/* Get listed as member of all the provided semaphores */
self->sem = (smx_sem_t)sems; /* FIXME: we pass a pointer to dynar where a pointer to sem is expected...*/
xbt_dynar_foreach(sems,counter,sem) {
- xbt_swag_insert(self, sem->sleeping);
+ xbt_fifo_push(sem->sleeping, self);
}
SIMIX_process_yield();
+ self->sem = NULL;
while (self->suspended)
SIMIX_process_yield();
- /* one of the semaphore unsuspended us -- great, let's search which one (and get out of the others) */
- self->sem = NULL;
+ /* at least one of the semaphore unsuspended us -- great, let's search the first one (and get out of the others) */
xbt_dynar_foreach(sems,counter,sem) {
- if (xbt_swag_belongs(self,sem->sleeping))
- xbt_swag_remove(self,sem->sleeping);
- else {
- xbt_assert0(result==-1,"More than one semaphore unlocked us. Dunno what to do");
+ if (!xbt_fifo_remove(sem->sleeping, self) && result == -1) {
+ if (sem->capacity != SMX_SEM_NOLIMIT) {
+ /* Take the released token */
+ sem->capacity--;
+ }
result = counter;
}
}
- xbt_assert0(counter!=-1,"Cannot find which semaphore unlocked me!");
+ xbt_assert0(result!=-1,"Cannot find which semaphore unlocked me!");
/* Destroy the waiting action */
self->waiting_action = NULL;