[PATCH] md: add a ->congested_fn function for raid5/6
This is very different from other raid levels and all requests go through a
'stripe cache', and it has congestion management already.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 6cea9c9..37e4ff6 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2593,6 +2593,24 @@
return ret;
}
+static int raid5_congested(void *data, int bits)
+{
+ mddev_t *mddev = data;
+ raid5_conf_t *conf = mddev_to_conf(mddev);
+
+ /* No difference between reads and writes. Just check
+ * how busy the stripe_cache is
+ */
+ if (conf->inactive_blocked)
+ return 1;
+ if (conf->quiesce)
+ return 1;
+ if (list_empty_careful(&conf->inactive_list))
+ return 1;
+
+ return 0;
+}
+
static int make_request(request_queue_t *q, struct bio * bi)
{
mddev_t *mddev = q->queuedata;
@@ -3296,6 +3314,9 @@
mddev->queue->unplug_fn = raid5_unplug_device;
mddev->queue->issue_flush_fn = raid5_issue_flush;
+ mddev->queue->backing_dev_info.congested_fn = raid5_congested;
+ mddev->queue->backing_dev_info.congested_data = mddev;
+
mddev->array_size = mddev->size * (conf->previous_raid_disks -
conf->max_degraded);