From mboxrd@z Thu Jan  1 00:00:00 1970
From: teigland@sourceware.org <teigland@sourceware.org>
Date: 20 Nov 2006 18:13:03 -0000
Subject: [Cluster-devel] cluster/group/gfs_controld plock.c
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CVSROOT:	/cvs/cluster
Module name:	cluster
Branch: 	RHEL50
Changes by:	teigland at sourceware.org	2006-11-20 18:13:03

Modified files:
	group/gfs_controld: plock.c 

Log message:
	The plock rate limiting code should use the full timeval to measure
	the 1 sec limit interval instead of just the rough difference in
	tv_sec values.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/cluster/group/gfs_controld/plock.c.diff?cvsroot=cluster&only_with_tag=RHEL50&r1=1.25.4.1&r2=1.25.4.2

--- cluster/group/gfs_controld/plock.c	2006/11/14 21:30:59	1.25.4.1
+++ cluster/group/gfs_controld/plock.c	2006/11/20 18:13:02	1.25.4.2
@@ -311,6 +311,21 @@
 	return control_fd;
 }
 
+static unsigned long time_diff_ms(struct timeval *begin, struct timeval *end)
+{
+	unsigned long a_us, b_us, c_us, s, us, ms;
+
+	a_us = begin->tv_sec * 1000000 + begin->tv_usec;
+	b_us = end->tv_sec * 1000000 + end->tv_usec;
+	c_us = b_us - a_us;
+
+	s = c_us / 1000000;
+	us = c_us % 1000000;
+	ms = us / 1000;
+
+	return (s * 1000 + ms);
+}
+
 int process_plocks(void)
 {
 	struct mountgroup *mg;
@@ -324,13 +339,13 @@
 	if (message_flow_control_on)
 		return 0;
 
-	/* do we want to do something a little more accurate than tv_sec? */
+	/* Every N ops we check how long it's taken to do those N ops.
+	   If it's less than 1000 ms, we don't take any more. */
 
-	/* limit plock rate within one second */
 	if (plock_rate_limit && plock_read_count &&
 	    !(plock_read_count % plock_rate_limit)) {
 		gettimeofday(&now, NULL);
-		if (now.tv_sec - plock_rate_last.tv_sec <= 0) {
+		if (time_diff_ms(&plock_rate_last, &now) < 1000) {
 			plock_rate_delays++;
 			return -EBUSY;
 		}