/* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this software; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307 USA * * As a special exception, the Free Software Foundation gives permission * for additional uses of the text contained in its release of GUILE. * * The exception is that, if you link the GUILE library with other files * to produce an executable, this does not by itself cause the * resulting executable to be covered by the GNU General Public License. * Your use of that executable is in no way restricted on account of * linking the GUILE library code into it. * * This exception does not however invalidate any other reasons why * the executable file might be covered by the GNU General Public License. * * This exception applies only to the code released by the * Free Software Foundation under the name GUILE. If you copy * code from other Free Software Foundation releases into a copy of * GUILE, as the General Public License permits, the exception does * not apply to the code that you add in this way. To avoid misleading * anyone as to the status of such modified files, you must delete * this exception notice from them. * * If you write modifications of your own for GUILE, it is your choice * whether to permit this exception to apply to your modifications. * If you do not wish that, delete this exception notice. */ /* $Id: coop.c,v 1.27.4.1 2001/10/06 16:28:34 mdj Exp $ */ /* Cooperative thread library, based on QuickThreads */ #include #ifdef HAVE_UNISTD_H #include #endif #include #include "qt/qt.h" #include "libguile/eval.h" /* #define COOP_STKSIZE (0x10000) */ #define COOP_STKSIZE (scm_eval_stack) /* `alignment' must be a power of 2. */ #define COOP_STKALIGN(sp, alignment) \ ((void *)((((qt_word_t)(sp)) + (alignment) - 1) & ~((alignment)-1))) /* Queue access functions. */ static void coop_qinit (coop_q_t *q) { q->t.next = q->tail = &q->t; q->t.all_prev = NULL; q->t.all_next = NULL; #ifdef GUILE_ISELECT q->t.nfds = 0; q->t.readfds = NULL; q->t.writefds = NULL; q->t.exceptfds = NULL; q->t.timeoutp = 0; #endif } coop_t * coop_qget (coop_q_t *q) { coop_t *t; t = q->t.next; q->t.next = t->next; if (t->next == &q->t) { if (t == &q->t) { /* If it was already empty .. */ return NULL; /* .. say so. */ } q->tail = &q->t; /* Else now it is empty. */ } return (t); } void coop_qput (coop_q_t *q, coop_t *t) { q->tail->next = t; t->next = &q->t; q->tail = t; } static void coop_all_qput (coop_q_t *q, coop_t *t) { if (q->t.all_next) q->t.all_next->all_prev = t; t->all_prev = NULL; t->all_next = q->t.all_next; q->t.all_next = t; } static void coop_all_qremove (coop_q_t *q, coop_t *t) { if (t->all_prev) t->all_prev->all_next = t->all_next; else q->t.all_next = t->all_next; if (t->all_next) t->all_next->all_prev = t->all_prev; } #ifdef GUILE_ISELECT /* Insert thread t into the ordered queue q. q is ordered after wakeup_time. Threads which aren't sleeping but waiting for I/O go last into the queue. */ void coop_timeout_qinsert (coop_q_t *q, coop_t *t) { coop_t *pred = &q->t; int sec = t->wakeup_time.tv_sec; int usec = t->wakeup_time.tv_usec; while (pred->next != &q->t && pred->next->timeoutp && (pred->next->wakeup_time.tv_sec < sec || (pred->next->wakeup_time.tv_sec == sec && pred->next->wakeup_time.tv_usec < usec))) pred = pred->next; t->next = pred->next; pred->next = t; if (t->next == &q->t) q->tail = t; } #endif /* Thread routines. */ coop_q_t coop_global_runq; /* A queue of runable threads. */ coop_q_t coop_global_sleepq; /* A queue of sleeping threads. */ coop_q_t coop_tmp_queue; /* A temp working queue */ coop_q_t coop_global_allq; /* A queue of all threads. */ static coop_t coop_global_main; /* Thread for the process. */ coop_t *coop_global_curr; /* Currently-executing thread. */ #ifdef GUILE_PTHREAD_COMPAT static coop_q_t coop_deadq; static int coop_quitting_p = -1; static pthread_cond_t coop_cond_quit; static pthread_cond_t coop_cond_create; static pthread_mutex_t coop_mutex_create; static pthread_t coop_mother; static int mother_awake_p = 0; static coop_t *coop_child; #endif static void *coop_starthelp (qt_t *old, void *ignore0, void *ignore1); static void coop_only (void *pu, void *pt, qt_userf_t *f); static void *coop_aborthelp (qt_t *sp, void *old, void *null); static void *coop_yieldhelp (qt_t *sp, void *old, void *blockq); /* called on process termination. */ #ifdef HAVE_ATEXIT static void coop_finish (void) #else #ifdef HAVE_ON_EXIT extern int on_exit (void (*procp) (), int arg); static void coop_finish (int status, void *arg) #else #error Dont know how to setup a cleanup handler on your system. #endif #endif { #ifdef GUILE_PTHREAD_COMPAT coop_quitting_p = 1; pthread_cond_signal (&coop_cond_create); pthread_cond_broadcast (&coop_cond_quit); #endif } void coop_init () { coop_qinit (&coop_global_runq); coop_qinit (&coop_global_sleepq); coop_qinit (&coop_tmp_queue); coop_qinit (&coop_global_allq); coop_global_curr = &coop_global_main; #ifdef GUILE_PTHREAD_COMPAT coop_qinit (&coop_deadq); pthread_cond_init (&coop_cond_quit, NULL); pthread_cond_init (&coop_cond_create, NULL); pthread_mutex_init (&coop_mutex_create, NULL); #endif #ifdef HAVE_ATEXIT atexit (coop_finish); #else #ifdef HAVE_ON_EXIT on_exit (coop_finish, 0); #endif #endif } /* Return the next runnable thread. If no threads are currently runnable, and there are sleeping threads - wait until one wakes up. Otherwise, return NULL. */ #ifndef GUILE_ISELECT coop_t * coop_next_runnable_thread() { int sleepers; coop_t *t; time_t now; do { sleepers = 0; now = time(NULL); /* Check the sleeping queue */ while ((t = coop_qget(&coop_global_sleepq)) != NULL) { sleepers++; if (t->wakeup_time <= now) coop_qput(&coop_global_runq, t); else coop_qput(&coop_tmp_queue, t); } while ((t = coop_qget(&coop_tmp_queue)) != NULL) coop_qput(&coop_global_sleepq, t); t = coop_qget (&coop_global_runq); } while ((t == NULL) && (sleepers > 0)); return t; } #endif void coop_start() { coop_t *next; while ((next = coop_qget (&coop_global_runq)) != NULL) { coop_global_curr = next; QT_BLOCK (coop_starthelp, 0, 0, next->sp); } } static void * coop_starthelp (qt_t *old, void *ignore0, void *ignore1) { coop_global_main.sp = old; coop_global_main.joining = NULL; coop_qput (&coop_global_runq, &coop_global_main); return NULL; /* not used, but keeps compiler happy */ } int coop_mutex_init (coop_m *m) { return coop_new_mutex_init (m, NULL); } int coop_new_mutex_init (coop_m *m, coop_mattr *attr) { m->owner = NULL; coop_qinit(&(m->waiting)); return 0; } int coop_mutex_trylock (coop_m *m) { if (m->owner == NULL) { m->owner = coop_global_curr; return 0; } else return EBUSY; } int coop_mutex_lock (coop_m *m) { if (m->owner == NULL) { m->owner = coop_global_curr; } else { coop_t *old, *newthread; /* Record the current top-of-stack before going to sleep */ coop_global_curr->top = &old; #ifdef GUILE_ISELECT newthread = coop_wait_for_runnable_thread(); if (newthread == coop_global_curr) coop_abort (); #else newthread = coop_next_runnable_thread(); #endif old = coop_global_curr; coop_global_curr = newthread; QT_BLOCK (coop_yieldhelp, old, &(m->waiting), newthread->sp); } return 0; } int coop_mutex_unlock (coop_m *m) { coop_t *old, *newthread; newthread = coop_qget (&(m->waiting)); if (newthread != NULL) { /* Record the current top-of-stack before going to sleep */ coop_global_curr->top = &old; old = coop_global_curr; coop_global_curr = newthread; /* The new thread came into m->waiting through a lock operation. It now owns this mutex. */ m->owner = coop_global_curr; QT_BLOCK (coop_yieldhelp, old, &coop_global_runq, newthread->sp); } else { m->owner = NULL; } return 0; } int coop_mutex_destroy (coop_m *m) { return 0; } int coop_condition_variable_init (coop_c *c) { return coop_new_condition_variable_init (c, NULL); } int coop_new_condition_variable_init (coop_c *c, coop_cattr *a) { coop_qinit(&(c->waiting)); return 0; } int coop_condition_variable_wait_mutex (coop_c *c, coop_m *m) { coop_t *old, *newthread; /* coop_mutex_unlock (m); */ newthread = coop_qget (&(m->waiting)); if (newthread != NULL) { m->owner = newthread; } else { m->owner = NULL; /*fixme* Should we really wait here? Isn't it OK just to proceed? */ #ifdef GUILE_ISELECT newthread = coop_wait_for_runnable_thread(); if (newthread == coop_global_curr) coop_abort (); #else newthread = coop_next_runnable_thread(); #endif } coop_global_curr->top = &old; old = coop_global_curr; coop_global_curr = newthread; QT_BLOCK (coop_yieldhelp, old, &(c->waiting), newthread->sp); coop_mutex_lock (m); return 0; } int coop_condition_variable_timed_wait_mutex (coop_c *c, coop_m *m, const struct timespec *abstime) { coop_t *old, *t; int res = ETIMEDOUT; /* coop_mutex_unlock (m); */ t = coop_qget (&(m->waiting)); if (t != NULL) { m->owner = t; } else { m->owner = NULL; #ifdef GUILE_ISELECT coop_global_curr->timeoutp = 1; coop_global_curr->wakeup_time.tv_sec = abstime->tv_sec; coop_global_curr->wakeup_time.tv_usec = abstime->tv_nsec / 1000; coop_timeout_qinsert (&coop_global_sleepq, coop_global_curr); t = coop_wait_for_runnable_thread(); #else /*fixme* Implement!*/ t = coop_next_runnable_thread(); #endif } if (t != coop_global_curr) { coop_global_curr->top = &old; old = coop_global_curr; coop_global_curr = t; QT_BLOCK (coop_yieldhelp, old, &(c->waiting), t->sp); /* Are we still in the sleep queue? */ old = &coop_global_sleepq.t; for (t = old->next; t != &coop_global_sleepq.t; old = t, t = t->next) if (t == coop_global_curr) { old->next = t->next; /* unlink */ res = 0; break; } } coop_mutex_lock (m); return res; } int coop_condition_variable_signal (coop_c *c) { coop_t *newthread; while ((newthread = coop_qget (&(c->waiting))) != NULL) { coop_qput (&coop_global_runq, newthread); } return 0; } /* {Keys} */ static int n_keys = 0; static int max_keys = 0; static void (**destructors) (void *) = 0; int coop_key_create (coop_k *keyp, void (*destructor) (void *value)) { if (n_keys >= max_keys) { int i; max_keys = max_keys ? max_keys * 3 / 2 : 10; destructors = realloc (destructors, sizeof (void *) * max_keys); if (destructors == 0) { fprintf (stderr, "Virtual memory exceeded in coop_key_create\n"); exit (1); } for (i = n_keys; i < max_keys; ++i) destructors[i] = NULL; } destructors[n_keys] = destructor; *keyp = n_keys++; return 0; } int coop_setspecific (coop_k key, const void *value) { int n_keys = coop_global_curr->n_keys; if (key >= n_keys) { int i; coop_global_curr->n_keys = max_keys; coop_global_curr->specific = realloc (n_keys ? coop_global_curr->specific : NULL, sizeof (void *) * max_keys); if (coop_global_curr->specific == 0) { fprintf (stderr, "Virtual memory exceeded in coop_setspecific\n"); exit (1); } for (i = n_keys; i < max_keys; ++i) coop_global_curr->specific[i] = NULL; } coop_global_curr->specific[key] = (void *) value; return 0; } void * coop_getspecific (coop_k key) { return (key < coop_global_curr->n_keys ? coop_global_curr->specific[key] : NULL); } int coop_key_delete (coop_k key) { return 0; } int coop_condition_variable_destroy (coop_c *c) { return 0; } #ifdef GUILE_PTHREAD_COMPAT /* 1K room for the cond wait routine */ #ifdef SCM_STACK_GROWS_UP #define COOP_STACK_ROOM (256) #else #define COOP_STACK_ROOM (-256) #endif static void * dummy_start (void *coop_thread) { coop_t *t = (coop_t *) coop_thread; int res; t->sp = (qt_t *) (&t + COOP_STACK_ROOM); pthread_mutex_init (&t->dummy_mutex, NULL); pthread_mutex_lock (&t->dummy_mutex); coop_child = 0; do res = pthread_cond_wait (&coop_cond_quit, &t->dummy_mutex); while (res == EINTR); return 0; } static void * mother (void *dummy) { pthread_mutex_lock (&coop_mutex_create); while (!coop_quitting_p) { int res; pthread_create (&coop_child->dummy_thread, NULL, dummy_start, coop_child); mother_awake_p = 0; do res = pthread_cond_wait (&coop_cond_create, &coop_mutex_create); while (res == EINTR); } return 0; } #endif coop_t * coop_create (coop_userf_t *f, void *pu) { coop_t *t; #ifndef GUILE_PTHREAD_COMPAT void *sto; #endif #ifdef GUILE_PTHREAD_COMPAT t = coop_qget (&coop_deadq); if (t) { t->sp = t->base; t->specific = 0; t->n_keys = 0; } else #endif { t = malloc (sizeof (coop_t)); t->specific = NULL; t->n_keys = 0; #ifdef GUILE_PTHREAD_COMPAT coop_child = t; mother_awake_p = 1; if (coop_quitting_p < 0) { coop_quitting_p = 0; /* We can't create threads ourselves since the pthread * corresponding to this stack might be sleeping. */ pthread_create (&coop_mother, NULL, mother, NULL); } else { pthread_cond_signal (&coop_cond_create); } /* We can't use a pthreads condition variable since "this" * pthread could already be asleep. We can't use a COOP * condition variable because they are not safe against * pre-emptive switching. */ while (coop_child || mother_awake_p) usleep (0); #else t->sto = malloc (COOP_STKSIZE); sto = COOP_STKALIGN (t->sto, QT_STKALIGN); t->sp = QT_SP (sto, COOP_STKSIZE - QT_STKALIGN); #endif t->base = t->sp; } t->sp = QT_ARGS (t->sp, pu, t, (qt_userf_t *)f, coop_only); t->joining = NULL; coop_qput (&coop_global_runq, t); coop_all_qput (&coop_global_allq, t); return t; } static void coop_only (void *pu, void *pt, qt_userf_t *f) { coop_global_curr = (coop_t *)pt; (*(coop_userf_t *)f)(pu); coop_abort(); /* NOTREACHED */ } void coop_abort () { coop_t *old, *newthread; /* Wake up any threads that are waiting to join this one */ if (coop_global_curr->joining) { while ((newthread = coop_qget ((coop_q_t *)(coop_global_curr->joining))) != NULL) { coop_qput (&coop_global_runq, newthread); } free (coop_global_curr->joining); } #ifdef GUILE_ISELECT scm_I_am_dead = 1; do { newthread = coop_wait_for_runnable_thread(); } while (newthread == coop_global_curr); scm_I_am_dead = 0; #else newthread = coop_next_runnable_thread(); #endif coop_all_qremove (&coop_global_allq, coop_global_curr); old = coop_global_curr; coop_global_curr = newthread; QT_ABORT (coop_aborthelp, old, (void *) NULL, newthread->sp); } static void * coop_aborthelp (qt_t *sp, void *old, void *null) { coop_t *oldthread = (coop_t *) old; if (oldthread->specific) free (oldthread->specific); #ifndef GUILE_PTHREAD_COMPAT free (oldthread->sto); free (oldthread); #else coop_qput (&coop_deadq, oldthread); #endif return NULL; } void coop_join(coop_t *t) { coop_t *old, *newthread; /* Create a join list if necessary */ if (t->joining == NULL) { t->joining = malloc(sizeof(coop_q_t)); coop_qinit((coop_q_t *) t->joining); } #ifdef GUILE_ISELECT newthread = coop_wait_for_runnable_thread(); if (newthread == coop_global_curr) return; #else newthread = coop_next_runnable_thread(); #endif old = coop_global_curr; coop_global_curr = newthread; QT_BLOCK (coop_yieldhelp, old, (coop_q_t *) t->joining, newthread->sp); } void coop_yield() { coop_t *old = NULL; coop_t *newthread; newthread = coop_next_runnable_thread(); /* There may be no other runnable threads. Return if this is the case. */ #if GUILE_ISELECT if (newthread == coop_global_curr) return; #else if (newthread == NULL) return; #endif old = coop_global_curr; coop_global_curr = newthread; QT_BLOCK (coop_yieldhelp, old, &coop_global_runq, newthread->sp); } static void * coop_yieldhelp (qt_t *sp, void *old, void *blockq) { ((coop_t *)old)->sp = sp; coop_qput ((coop_q_t *)blockq, (coop_t *)old); return NULL; } /* Replacement for the system's sleep() function. Does the right thing for the process - but not for the system (it busy-waits) */ void * coop_sleephelp (qt_t *sp, void *old, void *blockq) { ((coop_t *)old)->sp = sp; /* old is already on the sleep queue - so there's no need to do anything extra here */ return NULL; } #ifdef GUILE_ISELECT unsigned long scm_thread_usleep (unsigned long usec) { struct timeval timeout; timeout.tv_sec = 0; timeout.tv_usec = usec; scm_internal_select (0, NULL, NULL, NULL, &timeout); return 0; /* Maybe we should calculate actual time slept, but this is faster... :) */ } unsigned long scm_thread_sleep (unsigned long sec) { time_t now = time (NULL); struct timeval timeout; unsigned long slept; timeout.tv_sec = sec; timeout.tv_usec = 0; scm_internal_select (0, NULL, NULL, NULL, &timeout); slept = time (NULL) - now; return slept > sec ? 0 : sec - slept; } #else /* GUILE_ISELECT */ unsigned long scm_thread_sleep (unsigned long s) { coop_t *newthread, *old; time_t now = time (NULL); coop_global_curr->wakeup_time = now + s; /* Put the current thread on the sleep queue */ coop_qput (&coop_global_sleepq, coop_global_curr); newthread = coop_next_runnable_thread(); /* If newthread is the same as the sleeping thread, do nothing */ if (newthread == coop_global_curr) return s; old = coop_global_curr; coop_global_curr = newthread; QT_BLOCK (coop_sleephelp, old, NULL, newthread->sp); return s; } unsigned long scm_thread_usleep (unsigned long usec) { /* We're so cheap. */ scm_thread_sleep (usec / 1000000); struct timeval timeout; return 0; /* Maybe we should calculate actual time slept, but this is faster... :) */ } #endif /* GUILE_ISELECT */ /* Local Variables: c-file-style: "gnu" End: */