https://origsvn.digium.com/svn/asterisk/branches/1.4 ........ r142354 | russell | 2008-09-10 11:39:53 -0500 (Wed, 10 Sep 2008) | 7 lines It is a normal situation that a task gets put in the scheduler that should run as soon as possible. Accept "0" as an acceptable time to run, and also treat negative as "run now", and don't print a debug message about it. (inspired by a message asking about the "request to schedule in the past" debug message on the -dev list) ........ git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@142355 65c4cc65-6c06-0410-ace0-fbb531ad65f3
536 lines
14 KiB
C
536 lines
14 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 1999 - 2005, Digium, Inc.
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*
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* Mark Spencer <markster@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Scheduler Routines (from cheops-NG)
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*
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* \author Mark Spencer <markster@digium.com>
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*/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#ifdef DEBUG_SCHEDULER
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#define DEBUG(a) do { \
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if (option_debug) \
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DEBUG_M(a) \
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} while (0)
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#else
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#define DEBUG(a)
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#endif
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#include <sys/time.h>
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#include "asterisk/sched.h"
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#include "asterisk/channel.h"
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#include "asterisk/lock.h"
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#include "asterisk/utils.h"
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#include "asterisk/linkedlists.h"
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#include "asterisk/dlinkedlists.h"
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#include "asterisk/hashtab.h"
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struct sched {
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AST_DLLIST_ENTRY(sched) list;
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int id; /*!< ID number of event */
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struct timeval when; /*!< Absolute time event should take place */
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int resched; /*!< When to reschedule */
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int variable; /*!< Use return value from callback to reschedule */
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const void *data; /*!< Data */
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ast_sched_cb callback; /*!< Callback */
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};
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struct sched_context {
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ast_mutex_t lock;
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unsigned int eventcnt; /*!< Number of events processed */
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unsigned int schedcnt; /*!< Number of outstanding schedule events */
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unsigned int highwater; /*!< highest count so far */
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AST_DLLIST_HEAD_NOLOCK(, sched) schedq; /*!< Schedule entry and main queue */
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struct ast_hashtab *schedq_ht; /*!< hash table for fast searching */
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#ifdef SCHED_MAX_CACHE
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AST_LIST_HEAD_NOLOCK(, sched) schedc; /*!< Cache of unused schedule structures and how many */
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unsigned int schedccnt;
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#endif
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};
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/* hash routines for sched */
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static int sched_cmp(const void *a, const void *b)
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{
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const struct sched *as = a;
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const struct sched *bs = b;
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return as->id != bs->id; /* return 0 on a match like strcmp would */
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}
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static unsigned int sched_hash(const void *obj)
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{
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const struct sched *s = obj;
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unsigned int h = s->id;
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return h;
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}
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struct sched_context *sched_context_create(void)
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{
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struct sched_context *tmp;
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if (!(tmp = ast_calloc(1, sizeof(*tmp))))
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return NULL;
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ast_mutex_init(&tmp->lock);
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tmp->eventcnt = 1;
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tmp->schedq_ht = ast_hashtab_create(23, sched_cmp, ast_hashtab_resize_java, ast_hashtab_newsize_java, sched_hash, 1);
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return tmp;
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}
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void sched_context_destroy(struct sched_context *con)
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{
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struct sched *s;
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ast_mutex_lock(&con->lock);
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#ifdef SCHED_MAX_CACHE
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/* Eliminate the cache */
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while ((s = AST_LIST_REMOVE_HEAD(&con->schedc, list)))
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ast_free(s);
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#endif
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/* And the queue */
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while ((s = AST_DLLIST_REMOVE_HEAD(&con->schedq, list)))
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ast_free(s);
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ast_hashtab_destroy(con->schedq_ht, NULL);
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con->schedq_ht = NULL;
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/* And the context */
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ast_mutex_unlock(&con->lock);
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ast_mutex_destroy(&con->lock);
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ast_free(con);
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}
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static struct sched *sched_alloc(struct sched_context *con)
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{
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struct sched *tmp;
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/*
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* We keep a small cache of schedule entries
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* to minimize the number of necessary malloc()'s
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*/
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#ifdef SCHED_MAX_CACHE
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if ((tmp = AST_LIST_REMOVE_HEAD(&con->schedc, list)))
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con->schedccnt--;
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else
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#endif
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tmp = ast_calloc(1, sizeof(*tmp));
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return tmp;
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}
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static void sched_release(struct sched_context *con, struct sched *tmp)
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{
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/*
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* Add to the cache, or just free() if we
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* already have too many cache entries
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*/
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#ifdef SCHED_MAX_CACHE
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if (con->schedccnt < SCHED_MAX_CACHE) {
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AST_LIST_INSERT_HEAD(&con->schedc, tmp, list);
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con->schedccnt++;
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} else
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#endif
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ast_free(tmp);
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}
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/*! \brief
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* Return the number of milliseconds
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* until the next scheduled event
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*/
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int ast_sched_wait(struct sched_context *con)
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{
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int ms;
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DEBUG(ast_debug(1, "ast_sched_wait()\n"));
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ast_mutex_lock(&con->lock);
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if (AST_DLLIST_EMPTY(&con->schedq)) {
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ms = -1;
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} else {
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ms = ast_tvdiff_ms(AST_DLLIST_FIRST(&con->schedq)->when, ast_tvnow());
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if (ms < 0)
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ms = 0;
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}
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ast_mutex_unlock(&con->lock);
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return ms;
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}
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/*! \brief
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* Take a sched structure and put it in the
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* queue, such that the soonest event is
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* first in the list.
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*/
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static void schedule(struct sched_context *con, struct sched *s)
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{
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struct sched *cur = NULL;
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int ret;
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int df = 0;
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int de = 0;
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struct sched *first = AST_DLLIST_FIRST(&con->schedq);
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struct sched *last = AST_DLLIST_LAST(&con->schedq);
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if (first)
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df = ast_tvdiff_us(s->when, first->when);
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if (last)
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de = ast_tvdiff_us(s->when, last->when);
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if (df < 0)
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df = -df;
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if (de < 0)
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de = -de;
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if (df < de) {
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AST_DLLIST_TRAVERSE(&con->schedq, cur, list) {
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if (ast_tvcmp(s->when, cur->when) == -1) {
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AST_DLLIST_INSERT_BEFORE(&con->schedq, cur, s, list);
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break;
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}
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}
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if (!cur) {
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AST_DLLIST_INSERT_TAIL(&con->schedq, s, list);
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}
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} else {
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AST_DLLIST_TRAVERSE_BACKWARDS(&con->schedq, cur, list) {
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if (ast_tvcmp(s->when, cur->when) == 1) {
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AST_DLLIST_INSERT_AFTER(&con->schedq, cur, s, list);
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break;
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}
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}
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if (!cur) {
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AST_DLLIST_INSERT_HEAD(&con->schedq, s, list);
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}
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}
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ret = ast_hashtab_insert_safe(con->schedq_ht, s);
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if (!ret)
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ast_log(LOG_WARNING,"Schedule Queue entry %d is already in table!\n",s->id);
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con->schedcnt++;
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if (con->schedcnt > con->highwater)
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con->highwater = con->schedcnt;
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}
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/*! \brief
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* given the last event *tv and the offset in milliseconds 'when',
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* computes the next value,
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*/
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static int sched_settime(struct timeval *t, int when)
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{
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struct timeval now = ast_tvnow();
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/*ast_debug(1, "TV -> %lu,%lu\n", tv->tv_sec, tv->tv_usec);*/
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if (ast_tvzero(*t)) /* not supplied, default to now */
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*t = now;
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*t = ast_tvadd(*t, ast_samp2tv(when, 1000));
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if (ast_tvcmp(*t, now) < 0) {
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*t = now;
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}
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return 0;
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}
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int ast_sched_replace_variable(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable)
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{
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/* 0 means the schedule item is new; do not delete */
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if (old_id > 0) {
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AST_SCHED_DEL(con, old_id);
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}
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return ast_sched_add_variable(con, when, callback, data, variable);
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}
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/*! \brief
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* Schedule callback(data) to happen when ms into the future
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*/
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int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable)
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{
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struct sched *tmp;
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int res = -1;
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DEBUG(ast_debug(1, "ast_sched_add()\n"));
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ast_mutex_lock(&con->lock);
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if ((tmp = sched_alloc(con))) {
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tmp->id = con->eventcnt++;
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tmp->callback = callback;
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tmp->data = data;
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tmp->resched = when;
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tmp->variable = variable;
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tmp->when = ast_tv(0, 0);
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if (sched_settime(&tmp->when, when)) {
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sched_release(con, tmp);
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} else {
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schedule(con, tmp);
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res = tmp->id;
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}
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}
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#ifdef DUMP_SCHEDULER
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/* Dump contents of the context while we have the lock so nothing gets screwed up by accident. */
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if (option_debug)
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ast_sched_dump(con);
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#endif
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ast_mutex_unlock(&con->lock);
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return res;
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}
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int ast_sched_replace(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data)
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{
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if (old_id > -1) {
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AST_SCHED_DEL(con, old_id);
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}
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return ast_sched_add(con, when, callback, data);
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}
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int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, const void *data)
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{
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return ast_sched_add_variable(con, when, callback, data, 0);
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}
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const void *ast_sched_find_data(struct sched_context *con, int id)
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{
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struct sched tmp,*res;
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tmp.id = id;
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res = ast_hashtab_lookup(con->schedq_ht, &tmp);
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if (res)
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return res->data;
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return NULL;
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}
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/*! \brief
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* Delete the schedule entry with number
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* "id". It's nearly impossible that there
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* would be two or more in the list with that
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* id.
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*/
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#ifndef AST_DEVMODE
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int ast_sched_del(struct sched_context *con, int id)
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#else
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int _ast_sched_del(struct sched_context *con, int id, const char *file, int line, const char *function)
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#endif
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{
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struct sched *s, tmp;
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DEBUG(ast_debug(1, "ast_sched_del(%d)\n", id));
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ast_mutex_lock(&con->lock);
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/* OK, this is the heart of the sched performance upgrade.
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If we have 4700 peers, we can have 4700+ entries in the
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schedq list. searching this would take time. So, I add a
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hashtab to the context to keep track of each entry, by id.
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I also leave the linked list alone, almost, -- I implement
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a doubly-linked list instead, because it would do little good
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to look up the id in a hashtab, and then have to run thru
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a couple thousand entries to remove it from the schedq list! */
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tmp.id = id;
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s = ast_hashtab_lookup(con->schedq_ht, &tmp);
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if (s) {
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struct sched *x = AST_DLLIST_REMOVE(&con->schedq, s, list);
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if (!x)
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ast_log(LOG_WARNING,"sched entry %d not in the schedq list?\n", s->id);
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if (!ast_hashtab_remove_this_object(con->schedq_ht, s))
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ast_log(LOG_WARNING,"Found sched entry %d, then couldn't remove it?\n", s->id);
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con->schedcnt--;
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sched_release(con, s);
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}
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#ifdef DUMP_SCHEDULER
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/* Dump contents of the context while we have the lock so nothing gets screwed up by accident. */
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if (option_debug)
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ast_sched_dump(con);
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#endif
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ast_mutex_unlock(&con->lock);
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if (!s) {
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ast_debug(1, "Attempted to delete nonexistent schedule entry %d!\n", id);
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#ifndef AST_DEVMODE
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ast_assert(s != NULL);
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#else
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_ast_assert(0, "s != NULL", file, line, function);
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#endif
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return -1;
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}
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return 0;
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}
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char *ast_sched_report(struct sched_context *con, char *buf, int bufsiz, struct ast_cb_names *cbnames)
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{
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int *countlist,i;
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struct sched *cur;
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char buf2[1200];
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ast_sched_cb xxx = NULL;
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buf[0] = 0;
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sprintf(buf, " Highwater = %d\n schedcnt = %d\n", con->highwater, con->schedcnt);
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countlist = ast_calloc(sizeof(int),cbnames->numassocs+1);
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AST_DLLIST_TRAVERSE(&con->schedq, cur, list) {
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/* match the callback to the cblist */
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for (i=0;i<cbnames->numassocs;i++) {
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if (cur->callback == cbnames->cblist[i])
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break;
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}
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if (i < cbnames->numassocs)
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countlist[i]++;
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else {
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xxx = cur->callback;
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countlist[cbnames->numassocs]++;
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}
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}
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for (i=0;i<cbnames->numassocs;i++) {
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sprintf(buf2," %s : %d\n", cbnames->list[i], countlist[i]);
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strcat(buf, buf2);
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}
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sprintf(buf2," <unknown:%p> : %d\n", xxx, countlist[cbnames->numassocs]);
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strcat( buf, buf2);
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return buf;
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}
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/*! \brief Dump the contents of the scheduler to LOG_DEBUG */
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void ast_sched_dump(const struct sched_context *con)
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{
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struct sched *q;
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struct timeval when = ast_tvnow();
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#ifdef SCHED_MAX_CACHE
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ast_debug(1, "Asterisk Schedule Dump (%d in Q, %d Total, %d Cache, %d high-water)\n", con->schedcnt, con->eventcnt - 1, con->schedccnt, con->highwater);
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#else
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ast_debug(1, "Asterisk Schedule Dump (%d in Q, %d Total, %d high-water)\n", con->schedcnt, con->eventcnt - 1, con->highwater);
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#endif
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ast_debug(1, "=============================================================\n");
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ast_debug(1, "|ID Callback Data Time (sec:ms) |\n");
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ast_debug(1, "+-----+-----------------+-----------------+-----------------+\n");
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AST_DLLIST_TRAVERSE(&con->schedq, q, list) {
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struct timeval delta = ast_tvsub(q->when, when);
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ast_debug(1, "|%.4d | %-15p | %-15p | %.6ld : %.6ld |\n",
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q->id,
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q->callback,
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q->data,
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(long)delta.tv_sec,
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(long int)delta.tv_usec);
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}
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ast_debug(1, "=============================================================\n");
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}
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/*! \brief
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* Launch all events which need to be run at this time.
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*/
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int ast_sched_runq(struct sched_context *con)
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{
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struct sched *current;
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struct timeval when;
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int numevents;
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int res;
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DEBUG(ast_debug(1, "ast_sched_runq()\n"));
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ast_mutex_lock(&con->lock);
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for (numevents = 0; !AST_DLLIST_EMPTY(&con->schedq); numevents++) {
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/* schedule all events which are going to expire within 1ms.
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* We only care about millisecond accuracy anyway, so this will
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* help us get more than one event at one time if they are very
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* close together.
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*/
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when = ast_tvadd(ast_tvnow(), ast_tv(0, 1000));
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if (ast_tvcmp(AST_DLLIST_FIRST(&con->schedq)->when, when) != -1)
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break;
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current = AST_DLLIST_REMOVE_HEAD(&con->schedq, list);
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if (!ast_hashtab_remove_this_object(con->schedq_ht, current))
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ast_log(LOG_ERROR,"Sched entry %d was in the schedq list but not in the hashtab???\n", current->id);
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con->schedcnt--;
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/*
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* At this point, the schedule queue is still intact. We
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* have removed the first event and the rest is still there,
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* so it's permissible for the callback to add new events, but
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* trying to delete itself won't work because it isn't in
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* the schedule queue. If that's what it wants to do, it
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* should return 0.
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*/
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ast_mutex_unlock(&con->lock);
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res = current->callback(current->data);
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ast_mutex_lock(&con->lock);
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if (res) {
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/*
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* If they return non-zero, we should schedule them to be
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* run again.
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*/
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if (sched_settime(¤t->when, current->variable? res : current->resched)) {
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sched_release(con, current);
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} else
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schedule(con, current);
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} else {
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/* No longer needed, so release it */
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sched_release(con, current);
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}
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}
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ast_mutex_unlock(&con->lock);
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return numevents;
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}
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long ast_sched_when(struct sched_context *con,int id)
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{
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struct sched *s, tmp;
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long secs = -1;
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DEBUG(ast_debug(1, "ast_sched_when()\n"));
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ast_mutex_lock(&con->lock);
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/* these next 2 lines replace a lookup loop */
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tmp.id = id;
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s = ast_hashtab_lookup(con->schedq_ht, &tmp);
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if (s) {
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struct timeval now = ast_tvnow();
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secs = s->when.tv_sec - now.tv_sec;
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}
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ast_mutex_unlock(&con->lock);
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return secs;
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}
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