Fix up a problem that was introduced into the scheduler when it was converted
authorRussell Bryant <russell@russellbryant.com>
Wed, 7 May 2008 21:11:33 +0000 (21:11 +0000)
committerRussell Bryant <russell@russellbryant.com>
Wed, 7 May 2008 21:11:33 +0000 (21:11 +0000)
to use doubly linked lists.  The schedule() function had an optimization that
had it try to guess which direction would be better for the traversal to insert
the task into the scheduler queue.  However, if the code chose the path where
it traversed the queue in reverse, and the result was that the task should be
at the head of the queue, then the code would actually put it at the tail,
instead.

(Problem found by bbryant, debugged and fixed by bbryant and me)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@115537 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/sched.c

index d877417..64ef413 100644 (file)
@@ -198,34 +198,45 @@ static void schedule(struct sched_context *con, struct sched *s)
        int de = 0;
        struct sched *first = AST_DLLIST_FIRST(&con->schedq);
        struct sched *last = AST_DLLIST_LAST(&con->schedq);
+
        if (first)
                df = ast_tvdiff_us(s->when, first->when);
        if (last)
                de = ast_tvdiff_us(s->when, last->when);
+
        if (df < 0)
                df = -df;
        if (de < 0)
                de = -de;
-       if (df < de)
+
+       if (df < de) {
                AST_DLLIST_TRAVERSE(&con->schedq, cur, list) {
                        if (ast_tvcmp(s->when, cur->when) == -1) {
                                AST_DLLIST_INSERT_BEFORE(&con->schedq, cur, s, list);
                                break;
                        }
                }
-       else
+               if (!cur) {
+                       AST_DLLIST_INSERT_TAIL(&con->schedq, s, list);
+               }
+       } else {
                AST_DLLIST_TRAVERSE_BACKWARDS(&con->schedq, cur, list) {
                        if (ast_tvcmp(s->when, cur->when) == 1) {
                                AST_DLLIST_INSERT_AFTER(&con->schedq, cur, s, list);
                                break;
                        }
                }
-       if (!cur)
-               AST_DLLIST_INSERT_TAIL(&con->schedq, s, list);
+               if (!cur) {
+                       AST_DLLIST_INSERT_HEAD(&con->schedq, s, list);
+               }
+       }
+
        ret = ast_hashtab_insert_safe(con->schedq_ht, s);
        if (!ret)
                ast_log(LOG_WARNING,"Schedule Queue entry %d is already in table!\n",s->id);
+
        con->schedcnt++;
+
        if (con->schedcnt > con->highwater)
                con->highwater = con->schedcnt;
 }