diff --git a/sys/cam/ctl/ctl_backend_block.c b/sys/cam/ctl/ctl_backend_block.c
index eeddf1735bce..ae3a322c394e 100644
--- a/sys/cam/ctl/ctl_backend_block.c
+++ b/sys/cam/ctl/ctl_backend_block.c
@@ -580,9 +580,7 @@ ctl_be_block_flush_file(struct ctl_be_block_lun *be_lun,
 	DPRINTF("entered\n");
 
 	binuptime(&beio->ds_t0);
-	mtx_lock(&be_lun->io_lock);
 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
-	mtx_unlock(&be_lun->io_lock);
 
 	(void) vn_start_write(be_lun->vn, &mountpoint, V_WAIT);
 
@@ -663,9 +661,7 @@ ctl_be_block_dispatch_file(struct ctl_be_block_lun *be_lun,
 	}
 
 	binuptime(&beio->ds_t0);
-	mtx_lock(&be_lun->io_lock);
 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
-	mtx_unlock(&be_lun->io_lock);
 
 	if (beio->bio_cmd == BIO_READ) {
 		vn_lock(be_lun->vn, LK_SHARED | LK_RETRY);
@@ -894,9 +890,7 @@ ctl_be_block_dispatch_zvol(struct ctl_be_block_lun *be_lun,
 	}
 
 	binuptime(&beio->ds_t0);
-	mtx_lock(&be_lun->io_lock);
 	devstat_start_transaction(beio->lun->disk_stats, &beio->ds_t0);
-	mtx_unlock(&be_lun->io_lock);
 
 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
 	if (csw) {
@@ -1034,9 +1028,7 @@ ctl_be_block_flush_dev(struct ctl_be_block_lun *be_lun,
 	beio->send_complete = 1;
 
 	binuptime(&beio->ds_t0);
-	mtx_lock(&be_lun->io_lock);
 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
-	mtx_unlock(&be_lun->io_lock);
 
 	csw = devvn_refthread(be_lun->vn, &dev, &ref);
 	if (csw) {
@@ -1107,9 +1099,7 @@ ctl_be_block_unmap_dev(struct ctl_be_block_lun *be_lun,
 	DPRINTF("entered\n");
 
 	binuptime(&beio->ds_t0);
-	mtx_lock(&be_lun->io_lock);
 	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
-	mtx_unlock(&be_lun->io_lock);
 
 	if (beio->io_offset == -1) {
 		beio->io_len = 0;
@@ -1186,11 +1176,9 @@ ctl_be_block_dispatch_dev(struct ctl_be_block_lun *be_lun,
 			beio->num_bios_sent++;
 		}
 	}
-	binuptime(&beio->ds_t0);
-	mtx_lock(&be_lun->io_lock);
-	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
 	beio->send_complete = 1;
-	mtx_unlock(&be_lun->io_lock);
+	binuptime(&beio->ds_t0);
+	devstat_start_transaction(be_lun->disk_stats, &beio->ds_t0);
 
 	/*
 	 * Fire off all allocated requests!
diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 712f3e5aac30..adbefe86e200 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -247,7 +247,6 @@ struct md_s {
 	LIST_ENTRY(md_s) list;
 	struct bio_queue_head bio_queue;
 	struct mtx queue_mtx;
-	struct mtx stat_mtx;
 	struct cdev *dev;
 	enum md_types type;
 	off_t mediasize;
@@ -477,9 +476,7 @@ g_md_start(struct bio *bp)
 
 	sc = bp->bio_to->geom->softc;
 	if ((bp->bio_cmd == BIO_READ) || (bp->bio_cmd == BIO_WRITE)) {
-		mtx_lock(&sc->stat_mtx);
 		devstat_start_transaction_bio(sc->devstat, bp);
-		mtx_unlock(&sc->stat_mtx);
 	}
 	mtx_lock(&sc->queue_mtx);
 	bioq_disksort(&sc->bio_queue, bp);
@@ -1274,7 +1271,6 @@ mdnew(int unit, int *errp, enum md_types type)
 	sc->type = type;
 	bioq_init(&sc->bio_queue);
 	mtx_init(&sc->queue_mtx, "md bio queue", NULL, MTX_DEF);
-	mtx_init(&sc->stat_mtx, "md stat", NULL, MTX_DEF);
 	sc->unit = unit;
 	sprintf(sc->name, "md%d", unit);
 	LIST_INSERT_HEAD(&md_softc_list, sc, list);
@@ -1282,7 +1278,6 @@ mdnew(int unit, int *errp, enum md_types type)
 	if (error == 0)
 		return (sc);
 	LIST_REMOVE(sc, list);
-	mtx_destroy(&sc->stat_mtx);
 	mtx_destroy(&sc->queue_mtx);
 	free_unr(md_uh, sc->unit);
 	free(sc, M_MD);
@@ -1512,7 +1507,6 @@ mddestroy(struct md_s *sc, struct thread *td)
 	while (!(sc->flags & MD_EXITING))
 		msleep(sc->procp, &sc->queue_mtx, PRIBIO, "mddestroy", hz / 10);
 	mtx_unlock(&sc->queue_mtx);
-	mtx_destroy(&sc->stat_mtx);
 	mtx_destroy(&sc->queue_mtx);
 	if (sc->vnode != NULL) {
 		vn_lock(sc->vnode, LK_EXCLUSIVE | LK_RETRY);
diff --git a/sys/dev/nvdimm/nvdimm_spa.c b/sys/dev/nvdimm/nvdimm_spa.c
index 1e9d98e36ab6..3402df95d774 100644
--- a/sys/dev/nvdimm/nvdimm_spa.c
+++ b/sys/dev/nvdimm/nvdimm_spa.c
@@ -413,9 +413,7 @@ nvdimm_spa_g_start(struct bio *bp)
 
 	sc = bp->bio_to->geom->softc;
 	if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) {
-		mtx_lock(&sc->spa_g_stat_mtx);
 		devstat_start_transaction_bio(sc->spa_g_devstat, bp);
-		mtx_unlock(&sc->spa_g_stat_mtx);
 	}
 	mtx_lock(&sc->spa_g_mtx);
 	bioq_disksort(&sc->spa_g_queue, bp);
@@ -544,14 +542,12 @@ nvdimm_spa_g_create(struct nvdimm_spa_dev *dev, const char *name)
 	sc->dev = dev;
 	bioq_init(&sc->spa_g_queue);
 	mtx_init(&sc->spa_g_mtx, "spag", NULL, MTX_DEF);
-	mtx_init(&sc->spa_g_stat_mtx, "spagst", NULL, MTX_DEF);
 	sc->spa_g_proc_run = true;
 	sc->spa_g_proc_exiting = false;
 	error = kproc_create(nvdimm_spa_g_thread, sc, &sc->spa_g_proc, 0, 0,
 	    "g_spa");
 	if (error != 0) {
 		mtx_destroy(&sc->spa_g_mtx);
-		mtx_destroy(&sc->spa_g_stat_mtx);
 		free(sc, M_NVDIMM);
 		printf("NVDIMM %s cannot create geom worker, error %d\n", name,
 		    error);
@@ -621,7 +617,6 @@ nvdimm_spa_g_destroy_geom(struct gctl_req *req, struct g_class *cp,
 		sc->spa_g_devstat = NULL;
 	}
 	mtx_destroy(&sc->spa_g_mtx);
-	mtx_destroy(&sc->spa_g_stat_mtx);
 	free(sc, M_NVDIMM);
 	return (0);
 }
diff --git a/sys/dev/nvdimm/nvdimm_var.h b/sys/dev/nvdimm/nvdimm_var.h
index 6852875dc6a2..d69b1a70d8df 100644
--- a/sys/dev/nvdimm/nvdimm_var.h
+++ b/sys/dev/nvdimm/nvdimm_var.h
@@ -129,7 +129,6 @@ struct g_spa {
 	struct g_provider	*spa_p;
 	struct bio_queue_head	spa_g_queue;
 	struct mtx		spa_g_mtx;
-	struct mtx		spa_g_stat_mtx;
 	struct devstat		*spa_g_devstat;
 	struct proc		*spa_g_proc;
 	bool			spa_g_proc_run;
diff --git a/sys/geom/geom_disk.c b/sys/geom/geom_disk.c
index 40c70b2e07f9..8242e06f3dbf 100644
--- a/sys/geom/geom_disk.c
+++ b/sys/geom/geom_disk.c
@@ -64,13 +64,12 @@ __FBSDID("$FreeBSD$");
 #include <machine/bus.h>
 
 struct g_disk_softc {
-	struct mtx		 done_mtx;
 	struct disk		*dp;
 	struct sysctl_ctx_list	sysctl_ctx;
 	struct sysctl_oid	*sysctl_tree;
 	char			led[64];
 	uint32_t		state;
-	struct mtx		 start_mtx;
+	struct mtx		 done_mtx;
 };
 
 static g_access_t g_disk_access;
@@ -473,9 +472,7 @@ g_disk_start(struct bio *bp)
 			bp2->bio_pblkno = bp2->bio_offset / dp->d_sectorsize;
 			bp2->bio_bcount = bp2->bio_length;
 			bp2->bio_disk = dp;
-			mtx_lock(&sc->start_mtx); 
 			devstat_start_transaction_bio(dp->d_devstat, bp2);
-			mtx_unlock(&sc->start_mtx); 
 			dp->d_strategy(bp2);
 
 			if (bp3 == NULL)
@@ -559,9 +556,7 @@ g_disk_start(struct bio *bp)
 		}
 		bp2->bio_done = g_disk_done;
 		bp2->bio_disk = dp;
-		mtx_lock(&sc->start_mtx);
 		devstat_start_transaction_bio(dp->d_devstat, bp2);
-		mtx_unlock(&sc->start_mtx);
 		dp->d_strategy(bp2);
 		break;
 	default:
@@ -709,7 +704,6 @@ g_disk_create(void *arg, int flag)
 	mtx_pool_unlock(mtxpool_sleep, dp);
 
 	sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
-	mtx_init(&sc->start_mtx, "g_disk_start", NULL, MTX_DEF);
 	mtx_init(&sc->done_mtx, "g_disk_done", NULL, MTX_DEF);
 	sc->dp = dp;
 	gp = g_new_geomf(&g_disk_class, "%s%d", dp->d_name, dp->d_unit);
@@ -795,7 +789,6 @@ g_disk_providergone(struct g_provider *pp)
 	pp->private = NULL;
 	pp->geom->softc = NULL;
 	mtx_destroy(&sc->done_mtx);
-	mtx_destroy(&sc->start_mtx);
 	g_free(sc);
 }
 
diff --git a/sys/geom/geom_io.c b/sys/geom/geom_io.c
index eed5b14c5d05..da5ab0a1e976 100644
--- a/sys/geom/geom_io.c
+++ b/sys/geom/geom_io.c
@@ -490,7 +490,6 @@ void
 g_io_request(struct bio *bp, struct g_consumer *cp)
 {
 	struct g_provider *pp;
-	struct mtx *mtxp;
 	int direct, error, first;
 	uint8_t cmd;
 
@@ -545,11 +544,19 @@ g_io_request(struct bio *bp, struct g_consumer *cp)
 
 	KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
 	    ("Bio already on queue bp=%p", bp));
+
 	if ((g_collectstats & G_STATS_CONSUMERS) != 0 ||
 	    ((g_collectstats & G_STATS_PROVIDERS) != 0 && pp->stat != NULL))
 		binuptime(&bp->bio_t0);
 	else
 		getbinuptime(&bp->bio_t0);
+	if (g_collectstats & G_STATS_CONSUMERS)
+		devstat_start_transaction(cp->stat, &bp->bio_t0);
+	if (g_collectstats & G_STATS_PROVIDERS)
+		devstat_start_transaction(pp->stat, &bp->bio_t0);
+#ifdef INVARIANTS
+	atomic_add_int(&cp->nstart, 1);
+#endif
 
 #ifdef GET_STACK_USAGE
 	direct = (cp->flags & G_CF_DIRECT_SEND) != 0 &&
@@ -569,22 +576,6 @@ g_io_request(struct bio *bp, struct g_consumer *cp)
 	direct = 0;
 #endif
 
-	/*
-	 * The statistics collection is lockless, as such, but we
-	 * can not update one instance of the statistics from more
-	 * than one thread at a time, so grab the lock first.
-	 */
-	mtxp = mtx_pool_find(mtxpool_sleep, pp);
-	mtx_lock(mtxp);
-	if (g_collectstats & G_STATS_PROVIDERS)
-		devstat_start_transaction(pp->stat, &bp->bio_t0);
-	if (g_collectstats & G_STATS_CONSUMERS)
-		devstat_start_transaction(cp->stat, &bp->bio_t0);
-#ifdef INVARIANTS
-	cp->nstart++;
-#endif
-	mtx_unlock(mtxp);
-
 	if (direct) {
 		error = g_io_check(bp);
 		if (error >= 0) {
diff --git a/sys/kern/subr_devstat.c b/sys/kern/subr_devstat.c
index d837afb198cb..15b9126a43bb 100644
--- a/sys/kern/subr_devstat.c
+++ b/sys/kern/subr_devstat.c
@@ -227,8 +227,6 @@ void
 devstat_start_transaction(struct devstat *ds, const struct bintime *now)
 {
 
-	mtx_assert(&devstat_mutex, MA_NOTOWNED);
-
 	/* sanity check */
 	if (ds == NULL)
 		return;
@@ -239,13 +237,12 @@ devstat_start_transaction(struct devstat *ds, const struct bintime *now)
 	 * to busy.  The start time is really the start of the latest busy
 	 * period.
 	 */
-	if (ds->start_count == ds->end_count) {
+	if (atomic_fetchadd_int(&ds->start_count, 1) == ds->end_count) {
 		if (now != NULL)
 			ds->busy_from = *now;
 		else
 			binuptime(&ds->busy_from);
 	}
-	ds->start_count++;
 	atomic_add_rel_int(&ds->sequence0, 1);
 	DTRACE_DEVSTAT_START();
 }
@@ -254,8 +251,6 @@ void
 devstat_start_transaction_bio(struct devstat *ds, struct bio *bp)
 {
 
-	mtx_assert(&devstat_mutex, MA_NOTOWNED);
-
 	/* sanity check */
 	if (ds == NULL)
 		return;