cfq-iosched: fix the setting of IOPS mode on SSDs

A previous commit wanted to make CFQ default to IOPS mode on non-rotational storage, however it did so when the queue was initialized and the non-rotational flag is only set later on in the probe. Add an elevator hook that gets called off the add_disk() path, at that point we know that feature probing has finished, and we can reliably check for the various flags that drivers can set. Change-Id: Ieaf0beed1efc0ace7e61766e725647c6509e9852 Fixes: 41c0126b ("block: Make CFQ default to IOPS mode on SSDs") Tested-by: Romain Francoise <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
airend · Sep 18, 2015 · 87ae938 · 87ae938
1 parent a6876c8
commit 87ae938
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Showing 3 changed files with 18 additions and 1 deletion.
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
@@ -3744,7 +3744,7 @@ static void *cfq_init_queue(struct request_queue *q)
 	cfqd->cfq_slice[1] = cfq_slice_sync;
 	cfqd->cfq_target_latency = cfq_target_latency;
 	cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
-	cfqd->cfq_slice_idle = blk_queue_nonrot(q) ? 0 : cfq_slice_idle;
+	cfqd->cfq_slice_idle = cfq_slice_idle;
 	cfqd->cfq_group_idle = cfq_group_idle;
 	cfqd->cfq_latency = 1;
 	cfqd->hw_tag = -1;
@@ -3756,6 +3756,18 @@ static void *cfq_init_queue(struct request_queue *q)
 	return cfqd;
 }
 
+static void cfq_registered_queue(struct request_queue *q)
+{
+	struct elevator_queue *e = q->elevator;
+	struct cfq_data *cfqd = e->elevator_data;
+
+	/*
+	 * Default to IOPS mode with no idling for SSDs
+	 */
+	if (blk_queue_nonrot(q))
+		cfqd->cfq_slice_idle = 0;
+}
+
 /*
  * sysfs parts below -->
  */
@@ -3871,6 +3883,7 @@ static struct elevator_type iosched_cfq = {
 		.elevator_may_queue_fn =	cfq_may_queue,
 		.elevator_init_fn =		cfq_init_queue,
 		.elevator_exit_fn =		cfq_exit_queue,
+		.elevator_registered_fn =	cfq_registered_queue,
 	},
 	.icq_size	=	sizeof(struct cfq_io_cq),
 	.icq_align	=	__alignof__(struct cfq_io_cq),

diff --git a/block/elevator.c b/block/elevator.c
@@ -919,6 +919,8 @@ int __elv_register_queue(struct request_queue *q, struct elevator_queue *e)
 		}
 		kobject_uevent(&e->kobj, KOBJ_ADD);
 		e->registered = 1;
+		if (e->type->ops.elevator_registered_fn)
+			e->type->ops.elevator_registered_fn(q);
 	}
 	return error;
 }

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
@@ -38,6 +38,7 @@ typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct reques
 
 typedef void *(elevator_init_fn) (struct request_queue *);
 typedef void (elevator_exit_fn) (struct elevator_queue *);
+typedef void (elevator_registered_fn) (struct request_queue *);
 
 struct elevator_ops
 {
@@ -70,6 +71,7 @@ struct elevator_ops
 
 	elevator_init_fn *elevator_init_fn;
 	elevator_exit_fn *elevator_exit_fn;
+	elevator_registered_fn *elevator_registered_fn;
 };
 
 #define ELV_NAME_MAX	(16)