diff options
Diffstat (limited to 'main/sched.c')
-rw-r--r-- | main/sched.c | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/main/sched.c b/main/sched.c new file mode 100644 index 000000000..30b0af243 --- /dev/null +++ b/main/sched.c @@ -0,0 +1,399 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (C) 1999 - 2005, Digium, Inc. + * + * Mark Spencer <markster@digium.com> + * + * See http://www.asterisk.org for more information about + * the Asterisk project. Please do not directly contact + * any of the maintainers of this project for assistance; + * the project provides a web site, mailing lists and IRC + * channels for your use. + * + * This program is free software, distributed under the terms of + * the GNU General Public License Version 2. See the LICENSE file + * at the top of the source tree. + */ + +/*! \file + * + * \brief Scheduler Routines (from cheops-NG) + * + * \author Mark Spencer <markster@digium.com> + */ + +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision$") + +#ifdef DEBUG_SCHEDULER +#define DEBUG(a) do { \ + if (option_debug) \ + DEBUG_M(a) \ + } while (0) +#else +#define DEBUG(a) +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <sys/time.h> +#include <unistd.h> +#include <string.h> + +#include "asterisk/sched.h" +#include "asterisk/logger.h" +#include "asterisk/channel.h" +#include "asterisk/lock.h" +#include "asterisk/utils.h" +#include "asterisk/linkedlists.h" +#include "asterisk/options.h" + +struct sched { + AST_LIST_ENTRY(sched) list; + int id; /*!< ID number of event */ + struct timeval when; /*!< Absolute time event should take place */ + int resched; /*!< When to reschedule */ + int variable; /*!< Use return value from callback to reschedule */ + void *data; /*!< Data */ + ast_sched_cb callback; /*!< Callback */ +}; + +struct sched_context { + ast_mutex_t lock; + unsigned int eventcnt; /*!< Number of events processed */ + unsigned int schedcnt; /*!< Number of outstanding schedule events */ + AST_LIST_HEAD_NOLOCK(, sched) schedq; /*!< Schedule entry and main queue */ + +#ifdef SCHED_MAX_CACHE + AST_LIST_HEAD_NOLOCK(, sched) schedc; /*!< Cache of unused schedule structures and how many */ + unsigned int schedccnt; +#endif +}; + +struct sched_context *sched_context_create(void) +{ + struct sched_context *tmp; + + if (!(tmp = ast_calloc(1, sizeof(*tmp)))) + return NULL; + + ast_mutex_init(&tmp->lock); + tmp->eventcnt = 1; + + return tmp; +} + +void sched_context_destroy(struct sched_context *con) +{ + struct sched *s; + + ast_mutex_lock(&con->lock); + +#ifdef SCHED_MAX_CACHE + /* Eliminate the cache */ + while ((s = AST_LIST_REMOVE_HEAD(&con->schedc, list))) + free(s); +#endif + + /* And the queue */ + while ((s = AST_LIST_REMOVE_HEAD(&con->schedq, list))) + free(s); + + /* And the context */ + ast_mutex_unlock(&con->lock); + ast_mutex_destroy(&con->lock); + free(con); +} + +static struct sched *sched_alloc(struct sched_context *con) +{ + struct sched *tmp; + + /* + * We keep a small cache of schedule entries + * to minimize the number of necessary malloc()'s + */ +#ifdef SCHED_MAX_CACHE + if ((tmp = AST_LIST_REMOVE_HEAD(&con->schedc, list))) + con->schedccnt--; + else +#endif + tmp = ast_calloc(1, sizeof(*tmp)); + + return tmp; +} + +static void sched_release(struct sched_context *con, struct sched *tmp) +{ + /* + * Add to the cache, or just free() if we + * already have too many cache entries + */ + +#ifdef SCHED_MAX_CACHE + if (con->schedccnt < SCHED_MAX_CACHE) { + AST_LIST_INSERT_HEAD(&con->schedc, tmp, list); + con->schedccnt++; + } else +#endif + free(tmp); +} + +/*! \brief + * Return the number of milliseconds + * until the next scheduled event + */ +int ast_sched_wait(struct sched_context *con) +{ + int ms; + + DEBUG(ast_log(LOG_DEBUG, "ast_sched_wait()\n")); + + ast_mutex_lock(&con->lock); + if (AST_LIST_EMPTY(&con->schedq)) { + ms = -1; + } else { + ms = ast_tvdiff_ms(AST_LIST_FIRST(&con->schedq)->when, ast_tvnow()); + if (ms < 0) + ms = 0; + } + ast_mutex_unlock(&con->lock); + + return ms; +} + + +/*! \brief + * Take a sched structure and put it in the + * queue, such that the soonest event is + * first in the list. + */ +static void schedule(struct sched_context *con, struct sched *s) +{ + + struct sched *cur = NULL; + + AST_LIST_TRAVERSE_SAFE_BEGIN(&con->schedq, cur, list) { + if (ast_tvcmp(s->when, cur->when) == -1) { + AST_LIST_INSERT_BEFORE_CURRENT(&con->schedq, s, list); + break; + } + } + AST_LIST_TRAVERSE_SAFE_END + if (!cur) + AST_LIST_INSERT_TAIL(&con->schedq, s, list); + + con->schedcnt++; +} + +/*! \brief + * given the last event *tv and the offset in milliseconds 'when', + * computes the next value, + */ +static int sched_settime(struct timeval *tv, int when) +{ + struct timeval now = ast_tvnow(); + + /*ast_log(LOG_DEBUG, "TV -> %lu,%lu\n", tv->tv_sec, tv->tv_usec);*/ + if (ast_tvzero(*tv)) /* not supplied, default to now */ + *tv = now; + *tv = ast_tvadd(*tv, ast_samp2tv(when, 1000)); + if (ast_tvcmp(*tv, now) < 0) { + ast_log(LOG_DEBUG, "Request to schedule in the past?!?!\n"); + *tv = now; + } + return 0; +} + + +/*! \brief + * Schedule callback(data) to happen when ms into the future + */ +int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb callback, void *data, int variable) +{ + struct sched *tmp; + int res = -1; + DEBUG(ast_log(LOG_DEBUG, "ast_sched_add()\n")); + if (!when) { + ast_log(LOG_NOTICE, "Scheduled event in 0 ms?\n"); + return -1; + } + ast_mutex_lock(&con->lock); + if ((tmp = sched_alloc(con))) { + tmp->id = con->eventcnt++; + tmp->callback = callback; + tmp->data = data; + tmp->resched = when; + tmp->variable = variable; + tmp->when = ast_tv(0, 0); + if (sched_settime(&tmp->when, when)) { + sched_release(con, tmp); + } else { + schedule(con, tmp); + res = tmp->id; + } + } +#ifdef DUMP_SCHEDULER + /* Dump contents of the context while we have the lock so nothing gets screwed up by accident. */ + if (option_debug) + ast_sched_dump(con); +#endif + ast_mutex_unlock(&con->lock); + return res; +} + +int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, void *data) +{ + return ast_sched_add_variable(con, when, callback, data, 0); +} + +/*! \brief + * Delete the schedule entry with number + * "id". It's nearly impossible that there + * would be two or more in the list with that + * id. + */ +int ast_sched_del(struct sched_context *con, int id) +{ + struct sched *s; + + DEBUG(ast_log(LOG_DEBUG, "ast_sched_del()\n")); + + ast_mutex_lock(&con->lock); + AST_LIST_TRAVERSE_SAFE_BEGIN(&con->schedq, s, list) { + if (s->id == id) { + AST_LIST_REMOVE_CURRENT(&con->schedq, list); + con->schedcnt--; + sched_release(con, s); + break; + } + } + AST_LIST_TRAVERSE_SAFE_END + +#ifdef DUMP_SCHEDULER + /* Dump contents of the context while we have the lock so nothing gets screwed up by accident. */ + if (option_debug) + ast_sched_dump(con); +#endif + ast_mutex_unlock(&con->lock); + + if (!s) { + ast_log(LOG_NOTICE, "Attempted to delete nonexistent schedule entry %d!\n", id); +#ifdef DO_CRASH + CRASH; +#endif + return -1; + } + + return 0; +} + +/*! \brief Dump the contents of the scheduler to LOG_DEBUG */ +void ast_sched_dump(const struct sched_context *con) +{ + struct sched *q; + struct timeval tv = ast_tvnow(); +#ifdef SCHED_MAX_CACHE + ast_log(LOG_DEBUG, "Asterisk Schedule Dump (%d in Q, %d Total, %d Cache)\n", con->schedcnt, con->eventcnt - 1, con->schedccnt); +#else + ast_log(LOG_DEBUG, "Asterisk Schedule Dump (%d in Q, %d Total)\n", con->schedcnt, con->eventcnt - 1); +#endif + + ast_log(LOG_DEBUG, "=============================================================\n"); + ast_log(LOG_DEBUG, "|ID Callback Data Time (sec:ms) |\n"); + ast_log(LOG_DEBUG, "+-----+-----------------+-----------------+-----------------+\n"); + AST_LIST_TRAVERSE(&con->schedq, q, list) { + struct timeval delta = ast_tvsub(q->when, tv); + + ast_log(LOG_DEBUG, "|%.4d | %-15p | %-15p | %.6ld : %.6ld |\n", + q->id, + q->callback, + q->data, + delta.tv_sec, + (long int)delta.tv_usec); + } + ast_log(LOG_DEBUG, "=============================================================\n"); + +} + +/*! \brief + * Launch all events which need to be run at this time. + */ +int ast_sched_runq(struct sched_context *con) +{ + struct sched *current; + struct timeval tv; + int numevents; + int res; + + DEBUG(ast_log(LOG_DEBUG, "ast_sched_runq()\n")); + + ast_mutex_lock(&con->lock); + + for (numevents = 0; !AST_LIST_EMPTY(&con->schedq); numevents++) { + /* schedule all events which are going to expire within 1ms. + * We only care about millisecond accuracy anyway, so this will + * help us get more than one event at one time if they are very + * close together. + */ + tv = ast_tvadd(ast_tvnow(), ast_tv(0, 1000)); + if (ast_tvcmp(AST_LIST_FIRST(&con->schedq)->when, tv) != -1) + break; + + current = AST_LIST_REMOVE_HEAD(&con->schedq, list); + con->schedcnt--; + + /* + * At this point, the schedule queue is still intact. We + * have removed the first event and the rest is still there, + * so it's permissible for the callback to add new events, but + * trying to delete itself won't work because it isn't in + * the schedule queue. If that's what it wants to do, it + * should return 0. + */ + + ast_mutex_unlock(&con->lock); + res = current->callback(current->data); + ast_mutex_lock(&con->lock); + + if (res) { + /* + * If they return non-zero, we should schedule them to be + * run again. + */ + if (sched_settime(¤t->when, current->variable? res : current->resched)) { + sched_release(con, current); + } else + schedule(con, current); + } else { + /* No longer needed, so release it */ + sched_release(con, current); + } + } + + ast_mutex_unlock(&con->lock); + + return numevents; +} + +long ast_sched_when(struct sched_context *con,int id) +{ + struct sched *s; + long secs = -1; + DEBUG(ast_log(LOG_DEBUG, "ast_sched_when()\n")); + + ast_mutex_lock(&con->lock); + AST_LIST_TRAVERSE(&con->schedq, s, list) { + if (s->id == id) + break; + } + if (s) { + struct timeval now = ast_tvnow(); + secs = s->when.tv_sec - now.tv_sec; + } + ast_mutex_unlock(&con->lock); + + return secs; +} |