Re: 2.6.12-rc2 and as-iosched

[Jens Axboe <axboe@suse.de>]

On Mon, Jul 18 2005, Jens Axboe wrote:
> On Mon, Jul 18 2005, Kenneth Parrish wrote:
> > Randy> Need more info.
> > 
> >         Greetings.  :)
> > CONFIG_HZ_ changes the block device elevator time-out values -- didn't see.
> 
> I cannot reproduce here with cfq and HZ == 250, the jiffies <-> msec
> conversions are working fine. Please provide a proper bug report, did
> you change the values and not getting the expected back, or what is
> going wrong??

ok, AS is definitely broken, it does an internal HZ <-> msec conversion
in the store/show functions as well. This should fix it.

--- /opt/kernel/linux-2.6.13-rc3/drivers/block/as-iosched.c	2005-07-13 06:46:46.000000000 +0200
+++ linux-2.6.13-rc3/drivers/block/as-iosched.c	2005-07-18 15:46:23.000000000 +0200
@@ -1935,23 +1935,15 @@
 static ssize_t
 as_var_show(unsigned int var, char *page)
 {
-	var = (var * 1000) / HZ;
 	return sprintf(page, "%d\n", var);
 }
 
 static ssize_t
 as_var_store(unsigned long *var, const char *page, size_t count)
 {
-	unsigned long tmp;
 	char *p = (char *) page;
 
-	tmp = simple_strtoul(p, &p, 10);
-	if (tmp != 0) {
-		tmp = (tmp * HZ) / 1000;
-		if (tmp == 0)
-			tmp = 1;
-	}
-	*var = tmp;
+	*var = simple_strtoul(p, &p, 10);
 	return count;
 }
 

-- 
Jens Axboe