cfq: change the meaning of the cfqq_coop flag

commit b3b6d0408c953524f979468562e7e210d8634150 upstream

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>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 51fc2a54ca71bdf6b1bed6c9f63c514dc8612006..9a110a8cae1e8de120e7f8227315b9a97375c5d8 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -202,7 +202,7 @@ enum cfqq_state_flags {
        CFQ_CFQQ_FLAG_prio_changed,     /* task priority has changed */
        CFQ_CFQQ_FLAG_slice_new,        /* no requests dispatched in slice */
        CFQ_CFQQ_FLAG_sync,             /* synchronous queue */
-       CFQ_CFQQ_FLAG_coop,             /* has done a coop jump of the queue */
+       CFQ_CFQQ_FLAG_coop,             /* cfqq is shared */
        CFQ_CFQQ_FLAG_coop_preempt,     /* coop preempt */
 };
 
@@ -952,11 +952,8 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
 static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
                                              struct cfq_queue *cfqq)
 {
-       if (!cfqq) {
+       if (!cfqq)
                cfqq = cfq_get_next_queue(cfqd);
-               if (cfqq && !cfq_cfqq_coop_preempt(cfqq))
-                       cfq_clear_cfqq_coop(cfqq);
-       }
 
        if (cfqq)
                cfq_clear_cfqq_coop_preempt(cfqq);
@@ -1040,8 +1037,7 @@ 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,
-                                             bool probe)
+                                             struct cfq_queue *cur_cfqq)
 {
        struct cfq_queue *cfqq;
 
@@ -1060,11 +1056,6 @@ 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;
 }
 
@@ -1248,7 +1239,7 @@ 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.
         */
-       new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0);
+       new_cfqq = cfq_close_cooperator(cfqd, cfqq);
        if (new_cfqq) {
                if (!cfqq->new_cfqq)
                        cfq_setup_merge(cfqq, new_cfqq);
@@ -2313,7 +2304,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
                 */
                if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
                        cfq_slice_expired(cfqd, 1);
-               else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) &&
+               else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq) &&
                         sync && !rq_noidle(rq))
                        cfq_arm_slice_timer(cfqd);
        }
@@ -2414,6 +2405,7 @@ cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
 {
        cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
        cic_set_cfqq(cic, cfqq->new_cfqq, 1);
+       cfq_mark_cfqq_coop(cfqq->new_cfqq);
        cfq_put_queue(cfqq);
        return cic_to_cfqq(cic, 1);
 }