From 3ab0187add388d0895f0defd46e80d82a73a68fe Mon Sep 17 00:00:00 2001
From: Alexander Motin <mav@FreeBSD.org>
Date: Fri, 27 Mar 2015 12:44:28 +0000
Subject: [PATCH] Remove request sorting from GEOM_MIRROR and GEOM_RAID.

When CPU is not busy, those queues are typically empty.  When CPU is busy,
then one more extra sorting is the last thing it needs.  If specific device
(HDD) really needs sorting, then it will be done later by CAM.

This supposed to fix livelock reported for mirror of two SSDs, when UFS
fires zillion of BIO_DELETE requests, that totally blocks I/O subsystem by
pointless sorting of requests and responses under single mutex lock.

MFC after:	2 weeks
---
 sys/geom/mirror/g_mirror.c | 8 ++++----
 sys/geom/raid/g_raid.c     | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/sys/geom/mirror/g_mirror.c b/sys/geom/mirror/g_mirror.c
index 44e6fa10131..d46b3fa5311 100644
--- a/sys/geom/mirror/g_mirror.c
+++ b/sys/geom/mirror/g_mirror.c
@@ -888,7 +888,7 @@ g_mirror_done(struct bio *bp)
 	sc = bp->bio_from->geom->softc;
 	bp->bio_cflags = G_MIRROR_BIO_FLAG_REGULAR;
 	mtx_lock(&sc->sc_queue_mtx);
-	bioq_disksort(&sc->sc_queue, bp);
+	bioq_insert_tail(&sc->sc_queue, bp);
 	mtx_unlock(&sc->sc_queue_mtx);
 	wakeup(sc);
 }
@@ -975,7 +975,7 @@ g_mirror_regular_request(struct bio *bp)
 		else {
 			pbp->bio_error = 0;
 			mtx_lock(&sc->sc_queue_mtx);
-			bioq_disksort(&sc->sc_queue, pbp);
+			bioq_insert_tail(&sc->sc_queue, pbp);
 			mtx_unlock(&sc->sc_queue_mtx);
 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
 			wakeup(sc);
@@ -1015,7 +1015,7 @@ g_mirror_sync_done(struct bio *bp)
 	sc = bp->bio_from->geom->softc;
 	bp->bio_cflags = G_MIRROR_BIO_FLAG_SYNC;
 	mtx_lock(&sc->sc_queue_mtx);
-	bioq_disksort(&sc->sc_queue, bp);
+	bioq_insert_tail(&sc->sc_queue, bp);
 	mtx_unlock(&sc->sc_queue_mtx);
 	wakeup(sc);
 }
@@ -1144,7 +1144,7 @@ g_mirror_start(struct bio *bp)
 		return;
 	}
 	mtx_lock(&sc->sc_queue_mtx);
-	bioq_disksort(&sc->sc_queue, bp);
+	bioq_insert_tail(&sc->sc_queue, bp);
 	mtx_unlock(&sc->sc_queue_mtx);
 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
 	wakeup(sc);
diff --git a/sys/geom/raid/g_raid.c b/sys/geom/raid/g_raid.c
index 546bd207293..41566746dcf 100644
--- a/sys/geom/raid/g_raid.c
+++ b/sys/geom/raid/g_raid.c
@@ -1132,7 +1132,7 @@ g_raid_start(struct bio *bp)
 		return;
 	}
 	mtx_lock(&sc->sc_queue_mtx);
-	bioq_disksort(&sc->sc_queue, bp);
+	bioq_insert_tail(&sc->sc_queue, bp);
 	mtx_unlock(&sc->sc_queue_mtx);
 	if (!dumping) {
 		G_RAID_DEBUG1(4, sc, "Waking up %p.", sc);
@@ -1344,7 +1344,7 @@ g_raid_unlock_range(struct g_raid_volume *vol, off_t off, off_t len)
 			    (intmax_t)(lp->l_offset+lp->l_length));
 			mtx_lock(&sc->sc_queue_mtx);
 			while ((bp = bioq_takefirst(&vol->v_locked)) != NULL)
-				bioq_disksort(&sc->sc_queue, bp);
+				bioq_insert_tail(&sc->sc_queue, bp);
 			mtx_unlock(&sc->sc_queue_mtx);
 			free(lp, M_RAID);
 			return (0);
@@ -1438,7 +1438,7 @@ g_raid_disk_done(struct bio *bp)
 	sd = bp->bio_caller1;
 	sc = sd->sd_softc;
 	mtx_lock(&sc->sc_queue_mtx);
-	bioq_disksort(&sc->sc_queue, bp);
+	bioq_insert_tail(&sc->sc_queue, bp);
 	mtx_unlock(&sc->sc_queue_mtx);
 	if (!dumping)
 		wakeup(sc);