diff mbox

Re: Do not overload dispatch queue (Was: Re: IO scheduler based IO controller V10)

Message ID 1254653434.7237.18.camel@marge.simson.net (mailing list archive)
State New, archived
Headers show

Commit Message

Mike Galbraith Oct. 4, 2009, 10:50 a.m. UTC
None
diff mbox

Patch

Index: linux-2.6/block/cfq-iosched.c
===================================================================
--- linux-2.6.orig/block/cfq-iosched.c
+++ linux-2.6/block/cfq-iosched.c
@@ -1343,17 +1343,19 @@  static int cfq_dispatch_requests(struct
 	 */
 	if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_desktop) {
 		unsigned long last_sync = jiffies - cfqd->last_end_sync_rq;
+		unsigned long slice = max(cfq_slice_sync, cfq_slice_async);
 		unsigned int depth;
 
+		slice = min(slice, cfq_slice_async);
 		/*
 		 * must wait a bit longer
 		 */
-		if (last_sync < cfq_slice_sync) {
-			cfq_schedule_dispatch(cfqd, cfq_slice_sync - last_sync);
+		if (last_sync < slice) {
+			cfq_schedule_dispatch(cfqd, slice - last_sync);
 			return 0;
 		}
 
-		depth = last_sync / cfq_slice_sync;
+		depth = last_sync / slice;
 		if (depth < max_dispatch)
 			max_dispatch = depth;
 	}