From: Jeff Moyer <jmoyer@redhat.com>
Date: Tue, 3 Nov 2009 11:36:43 -0500
Subject: [block] cfq: change the meaning of the cfqq_coop flag
Message-id: 1257266206-24003-10-git-send-email-jmoyer@redhat.com
O-Subject: [PATCH 09/12] cfq: change the meaning of the cfqq_coop flag
Bugzilla: 456181 448130 427709
RH-Acked-by: Josef Bacik <josef@redhat.com>
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Vivek Goyal <vgoyal@redhat.com>

commit b3b6d0408c953524f979468562e7e210d8634150
Author: Jeff Moyer <jmoyer@redhat.com>
Date:   Fri Oct 23 17:14:51 2009 -0400

    cfq: change the meaning of the cfqq_coop flag

    The flag used to indicate that a cfqq was allowed to jump ahead in the
    scheduling order due to submitting a request close to the queue that
    just executed.  Since closely cooperating queues are now merged, the flag
    holds little meaning.  Change it to indicate that multiple queues were
    merged.  This will later be used to allow the breaking up of merged queues
    when they are no longer cooperating.

    Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
    Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 9d38fd8..69c906f 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1019,9 +1019,6 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
 			mod_timer(&cfqd->idle_class_timer, end);
 	}
 
-	if (cfqq)
-		cfq_clear_cfqq_coop(cfqq);
-
 set_queue:
 	__cfq_set_active_queue(cfqd, cfqq);
 	return cfqq;
@@ -1079,8 +1076,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
  * assumption.
  */
 static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
-					      struct cfq_queue *cur_cfqq,
-					      int probe)
+					      struct cfq_queue *cur_cfqq)
 {
 	struct cfq_queue *cfqq;
 
@@ -1099,11 +1095,6 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
 	if (!cfq_cfqq_sync(cfqq))
 		return NULL;
 
-	if (cfq_cfqq_coop(cfqq))
-		return NULL;
-
-	if (!probe)
-		cfq_mark_cfqq_coop(cfqq);
 	return cfqq;
 }
 
@@ -1287,7 +1278,7 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
 	 * cooperators and put the close queue at the front of the service
 	 * tree.  If possible, merge the expiring queue with the new cfqq.
 	 */
-	else if ((new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0))) {
+	else if ((new_cfqq = cfq_close_cooperator(cfqd, cfqq))) {
 		if (!cfqq->new_cfqq)
 			cfq_setup_merge(cfqq, new_cfqq);
 		goto expire;
@@ -2152,7 +2143,7 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
 		if (time_after(now, cfqq->slice_end))
 			cfq_slice_expired(cfqd, 0);
 		else if (cfqq_empty &&
-			 !cfq_close_cooperator(cfqd, cfqq, 1) && sync)
+			 !cfq_close_cooperator(cfqd, cfqq) && sync)
 			cfq_arm_slice_timer(cfqd, cfqq);
 	}
 
@@ -2301,6 +2292,7 @@ cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
 		struct cfq_queue *cfqq)
 {
 	cic->cfqq[SYNC] = cfqq->new_cfqq;
+	cfq_mark_cfqq_coop(cfqq->new_cfqq);
 	cfq_put_queue(cfqq);
 	return cic->cfqq[SYNC];
 }