/* * Ouroboros - Copyright (C) 2016 - 2017 * * Timerwheel * * Dimitri Staessens * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * 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 program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include #define FRAC 10 /* accuracy of the timer */ #define tw_used(tw) ((tw->head + tw->elements - tw->tail) & (tw->elements - 1)); #define tw_free(tw) (tw_used(tw) + 1 < tw->elements) #define tw_empty(tw) (tw->head == tw->tail) enum tw_state { TW_NULL = 0, TW_RUNNING, TW_DESTROY }; struct tw_f { struct list_head next; void (* func)(void *); void * arg; }; struct tw_el { struct list_head funcs; struct timespec expiry; }; struct timerwheel { struct tw_el * wheel; struct timespec intv; size_t pos; struct list_head wq; pthread_cond_t work; pthread_mutex_t lock; int resolution; unsigned int elements; enum tw_state state; pthread_mutex_t s_lock; pthread_t ticker; pthread_t worker; }; static void tw_el_fini(struct tw_el * e) { struct list_head * p; struct list_head * h; list_for_each_safe(p, h, &e->funcs) { struct tw_f * f = list_entry(p, struct tw_f, next); list_del(&f->next); if (f->arg != NULL) free(f->arg); } } static enum tw_state tw_get_state(struct timerwheel * tw) { enum tw_state state; assert(tw); pthread_mutex_lock(&tw->s_lock); state = tw->state; pthread_mutex_unlock(&tw->s_lock); return state; } static void tw_set_state(struct timerwheel * tw, enum tw_state state) { assert(tw); assert(state != TW_NULL); pthread_mutex_lock(&tw->s_lock); tw->state = state; pthread_mutex_unlock(&tw->s_lock); } static void * worker(void * o) { struct list_head * p; struct list_head * h; struct timerwheel * tw = (struct timerwheel *) o; struct timespec dl; struct timespec now; clock_gettime(PTHREAD_COND_CLOCK, &now); ts_add(&now, &tw->intv, &dl); pthread_mutex_lock(&tw->lock); while (tw_get_state(tw) == TW_RUNNING) { if (pthread_cond_timedwait(&tw->work, &tw->lock, &dl) == ETIMEDOUT) ts_add(&dl, &tw->intv, &dl); list_for_each_safe(p, h, &tw->wq) { struct tw_f * f = list_entry(p, struct tw_f, next); list_del(&f->next); pthread_mutex_unlock(&tw->lock); f->func(f->arg); if (f->arg != NULL) free(f->arg); free(f); pthread_mutex_lock(&tw->lock); } } pthread_mutex_unlock(&tw->lock); return (void *) o; } static void * movement(void * o) { struct timerwheel * tw = (struct timerwheel *) o; struct timespec now = {0, 0}; long ms = tw->resolution * tw->elements; struct timespec total = {ms / 1000, (ms % 1000) * MILLION}; struct list_head * p; struct list_head * h; while (tw_get_state(tw) == TW_RUNNING) { clock_gettime(CLOCK_MONOTONIC, &now); pthread_mutex_lock(&tw->lock); if (ts_diff_us(&tw->wheel[tw->pos].expiry, &now) < 0) { pthread_mutex_unlock(&tw->lock); nanosleep(&tw->intv, NULL); continue; } list_for_each_safe(p, h, &tw->wheel[tw->pos].funcs) { struct tw_f * f = list_entry(p, struct tw_f, next); list_del(&f->next); list_add(&f->next, &tw->wq); } ts_add(&tw->wheel[tw->pos].expiry, &total, &tw->wheel[tw->pos].expiry); tw->pos = (tw->pos + 1) & (tw->elements - 1); pthread_cond_signal(&tw->work); pthread_mutex_unlock(&tw->lock); } return (void *) 0; } struct timerwheel * timerwheel_create(unsigned int resolution, unsigned int max_delay) { struct timespec now = {0, 0}; struct timespec res_ts = {resolution / 1000, (resolution % 1000) * MILLION}; unsigned long i; struct timerwheel * tw; pthread_condattr_t cattr; assert(resolution != 0); tw = malloc(sizeof(*tw)); if (tw == NULL) return NULL; if (pthread_mutex_init(&tw->lock, NULL)) return NULL; tw->elements = 1; while (tw->elements < max_delay / resolution) tw->elements <<= 1; tw->wheel = malloc(sizeof(*tw->wheel) * tw->elements); if (tw->wheel == NULL) { free(tw); return NULL; } tw->resolution = resolution; tw->intv.tv_sec = (tw->resolution / FRAC) / 1000; tw->intv.tv_nsec = ((tw->resolution / FRAC) % 1000) * MILLION; list_head_init(&tw->wq); if (pthread_mutex_init(&tw->lock, NULL)) { free(tw->wheel); free(tw); return NULL; } if (pthread_mutex_init(&tw->s_lock, NULL)) { pthread_mutex_destroy(&tw->lock); free(tw->wheel); free(tw); return NULL; } if (pthread_condattr_init(&cattr)) { pthread_mutex_destroy(&tw->lock); free(tw->wheel); free(tw); return NULL; } #ifndef __APPLE__ pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK); #endif if (pthread_cond_init(&tw->work, &cattr)) { pthread_mutex_destroy(&tw->s_lock); pthread_mutex_destroy(&tw->lock); free(tw->wheel); free(tw); return NULL; } tw->pos = 0; tw->state = TW_RUNNING; clock_gettime(CLOCK_MONOTONIC, &now); now.tv_nsec -= (now.tv_nsec % MILLION); for (i = 0; i < tw->elements; ++i) { list_head_init(&tw->wheel[i].funcs); tw->wheel[i].expiry = now; ts_add(&now, &res_ts, &now); } if (pthread_create(&tw->worker, NULL, worker, (void *) tw)) { pthread_cond_destroy(&tw->work); pthread_mutex_destroy(&tw->s_lock); pthread_mutex_destroy(&tw->lock); free(tw->wheel); free(tw); return NULL; } if (pthread_create(&tw->ticker, NULL, movement, (void *) tw)) { tw_set_state(tw, TW_DESTROY); pthread_join(tw->worker, NULL); pthread_cond_destroy(&tw->work); pthread_mutex_destroy(&tw->s_lock); pthread_mutex_destroy(&tw->lock); free(tw->wheel); free(tw); return NULL; } return tw; } void timerwheel_destroy(struct timerwheel * tw) { unsigned long i; struct list_head * p; struct list_head * h; tw_set_state(tw, TW_DESTROY); pthread_join(tw->ticker, NULL); pthread_join(tw->worker, NULL); for (i = 0; i < tw->elements; ++i) tw_el_fini(&tw->wheel[i]); pthread_mutex_lock(&tw->lock); list_for_each_safe(p, h, &tw->wq) { struct tw_f * f = list_entry(p, struct tw_f, next); list_del(&f->next); if (f->arg != NULL) free(f->arg); free(f); } pthread_mutex_unlock(&tw->lock); pthread_cond_destroy(&tw->work); pthread_mutex_destroy(&tw->lock); pthread_mutex_destroy(&tw->s_lock); free(tw->wheel); free(tw); } int timerwheel_add(struct timerwheel * tw, void (* func)(void *), void * arg, size_t arg_len, unsigned int delay) { int pos; struct tw_f * f = malloc(sizeof(*f)); if (f == NULL) return -ENOMEM; f->func = func; f->arg = malloc(arg_len); if (f->arg == NULL) { free(f); return -ENOMEM; } memcpy(f->arg, arg, arg_len); assert(delay < tw->elements * tw->resolution); pthread_mutex_lock(&tw->lock); pos = (tw->pos + delay / tw->resolution) & (tw->elements - 1); list_add(&f->next, &tw->wheel[pos].funcs); pthread_mutex_unlock(&tw->lock); return 0; }