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.
Fixes: 41c0126b ("block: Make CFQ default to IOPS mode on SSDs")
Tested-by: Romain Francoise <romain@orebokech.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index c808ad8..d1d0cb2 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -4508,7 +4508,7 @@
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;
@@ -4525,6 +4525,18 @@
return ret;
}
+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 -->
*/
@@ -4640,6 +4652,7 @@
.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),