[asterisk-commits] russell: trunk r115537 - /trunk/main/sched.c

[SVN commits to the Asterisk project]

Author: russell
Date: Wed May  7 16:11:33 2008
New Revision: 115537

URL: http://svn.digium.com/view/asterisk?view=rev&rev=115537
Log:
Fix up a problem that was introduced into the scheduler when it was converted
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)

Modified:
    trunk/main/sched.c

Modified: trunk/main/sched.c
URL: http://svn.digium.com/view/asterisk/trunk/main/sched.c?view=diff&rev=115537&r1=115536&r2=115537
==============================================================================
--- trunk/main/sched.c (original)
+++ trunk/main/sched.c Wed May  7 16:11:33 2008
@@ -198,34 +198,45 @@
 	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;
 }