diff --git a/CHANGELOG.md b/CHANGELOG.md
index 36a181c3c..a9c24d253 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -39,6 +39,12 @@ taken into account if trying to achieve an artificial latency on top of an nvme
 Added spdk_nvme_ctrlr_get_transport_id() to get the transport ID from a
 previously attached controller.
 
+### env
+
+The parameter `free_space` has been added to spdk_ring_enqueue() to wait when
+the ring is almost full and resume when there is enough space available in
+the ring.
+
 ## v19.04:
 
 ### nvme
diff --git a/include/spdk/env.h b/include/spdk/env.h
index 0203c8d53..25f1542a9 100644
--- a/include/spdk/env.h
+++ b/include/spdk/env.h
@@ -582,10 +582,12 @@ size_t spdk_ring_count(struct spdk_ring *ring);
  * \param ring A pointer to the ring.
  * \param objs A pointer to the array to be queued.
  * \param count Length count of the array of objects.
+ * \param free_space If non-NULL, amount of free space after the enqueue has finished.
  *
  * \return the number of objects enqueued.
  */
-size_t spdk_ring_enqueue(struct spdk_ring *ring, void **objs, size_t count);
+size_t spdk_ring_enqueue(struct spdk_ring *ring, void **objs, size_t count,
+			 size_t *free_space);
 
 /**
  * Dequeue count objects from the ring into the array objs.
diff --git a/lib/bdev/nvme/bdev_ftl.c b/lib/bdev/nvme/bdev_ftl.c
index 4acec500c..32657320d 100644
--- a/lib/bdev/nvme/bdev_ftl.c
+++ b/lib/bdev/nvme/bdev_ftl.c
@@ -247,7 +247,7 @@ bdev_ftl_cb(void *arg, int status)
 
 	io->status = status;
 
-	cnt = spdk_ring_enqueue(io->ring, (void **)&io, 1);
+	cnt = spdk_ring_enqueue(io->ring, (void **)&io, 1, NULL);
 	assert(cnt == 1);
 }
 
diff --git a/lib/bdev/virtio/bdev_virtio_scsi.c b/lib/bdev/virtio/bdev_virtio_scsi.c
index cf555f03f..b770a19b6 100644
--- a/lib/bdev/virtio/bdev_virtio_scsi.c
+++ b/lib/bdev/virtio/bdev_virtio_scsi.c
@@ -570,7 +570,7 @@ bdev_virtio_reset(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
 	tmf_req->type = VIRTIO_SCSI_T_TMF;
 	tmf_req->subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET;
 
-	enqueued_count = spdk_ring_enqueue(svdev->ctrlq_ring, (void **)&bdev_io, 1);
+	enqueued_count = spdk_ring_enqueue(svdev->ctrlq_ring, (void **)&bdev_io, 1, NULL);
 	if (spdk_likely(enqueued_count == 1)) {
 		return;
 	} else {
diff --git a/lib/env_dpdk/env.c b/lib/env_dpdk/env.c
index 073881583..0421ade73 100644
--- a/lib/env_dpdk/env.c
+++ b/lib/env_dpdk/env.c
@@ -393,9 +393,11 @@ spdk_ring_count(struct spdk_ring *ring)
 }
 
 size_t
-spdk_ring_enqueue(struct spdk_ring *ring, void **objs, size_t count)
+spdk_ring_enqueue(struct spdk_ring *ring, void **objs, size_t count,
+		  size_t *free_space)
 {
-	return rte_ring_enqueue_bulk((struct rte_ring *)ring, objs, count, NULL);
+	return rte_ring_enqueue_bulk((struct rte_ring *)ring, objs, count,
+				     (unsigned int *)free_space);
 }
 
 size_t
diff --git a/lib/event/reactor.c b/lib/event/reactor.c
index eae3d6d42..e93b9c904 100644
--- a/lib/event/reactor.c
+++ b/lib/event/reactor.c
@@ -135,7 +135,7 @@ spdk_event_call(struct spdk_event *event)
 	reactor = spdk_reactor_get(event->lcore);
 
 	assert(reactor->events != NULL);
-	rc = spdk_ring_enqueue(reactor->events, (void **)&event, 1);
+	rc = spdk_ring_enqueue(reactor->events, (void **)&event, 1, NULL);
 	if (rc != 1) {
 		assert(false);
 	}
diff --git a/lib/ftl/ftl_reloc.c b/lib/ftl/ftl_reloc.c
index d00e8b5df..8395cce39 100644
--- a/lib/ftl/ftl_reloc.c
+++ b/lib/ftl/ftl_reloc.c
@@ -158,7 +158,7 @@ _ftl_reloc_prep(struct ftl_band_reloc *breloc)
 
 	for (i = 0; i < reloc->max_qdepth; ++i) {
 		io = ftl_io_alloc(dev->ioch);
-		spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1);
+		spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1, NULL);
 	}
 }
 
@@ -215,7 +215,7 @@ ftl_reloc_free_io(struct ftl_band_reloc *breloc, struct ftl_io *io)
 {
 	spdk_dma_free(io->iov[0].iov_base);
 	free(io->lba.vector);
-	spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1);
+	spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1, NULL);
 }
 
 static void
@@ -257,7 +257,7 @@ ftl_reloc_read_cb(void *arg, int status)
 	}
 
 	io->flags &= ~FTL_IO_INITIALIZED;
-	spdk_ring_enqueue(breloc->write_queue, (void **)&io, 1);
+	spdk_ring_enqueue(breloc->write_queue, (void **)&io, 1, NULL);
 }
 
 static void
@@ -465,7 +465,7 @@ ftl_reloc_read(struct ftl_band_reloc *breloc, struct ftl_io *io)
 	num_lbks = ftl_reloc_next_lbks(breloc, &ppa);
 
 	if (!num_lbks) {
-		spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1);
+		spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1, NULL);
 		return 0;
 	}
 
diff --git a/lib/ftl/ftl_rwb.c b/lib/ftl/ftl_rwb.c
index 58e1d4392..0af06525f 100644
--- a/lib/ftl/ftl_rwb.c
+++ b/lib/ftl/ftl_rwb.c
@@ -368,7 +368,7 @@ ftl_rwb_batch_revert(struct ftl_rwb_batch *batch)
 {
 	struct ftl_rwb *rwb = batch->rwb;
 
-	if (spdk_ring_enqueue(rwb->prio_queue, (void **)&batch, 1) != 1) {
+	if (spdk_ring_enqueue(rwb->prio_queue, (void **)&batch, 1, NULL) != 1) {
 		assert(0 && "Should never happen");
 	}
 }
@@ -385,7 +385,7 @@ ftl_rwb_push(struct ftl_rwb_entry *entry)
 	/* Once all of the entries are put back, push the batch on the */
 	/* submission queue */
 	if (ftl_rwb_batch_full(batch, batch_size)) {
-		if (spdk_ring_enqueue(rwb->submit_queue, (void **)&batch, 1) != 1) {
+		if (spdk_ring_enqueue(rwb->submit_queue, (void **)&batch, 1, NULL) != 1) {
 			assert(0 && "Should never happen");
 		}
 	}
diff --git a/lib/thread/thread.c b/lib/thread/thread.c
index a10a773cf..471417ce1 100644
--- a/lib/thread/thread.c
+++ b/lib/thread/thread.c
@@ -692,7 +692,7 @@ spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx
 	msg->fn = fn;
 	msg->arg = ctx;
 
-	rc = spdk_ring_enqueue(thread->messages, (void **)&msg, 1);
+	rc = spdk_ring_enqueue(thread->messages, (void **)&msg, 1, NULL);
 	if (rc != 1) {
 		assert(false);
 		spdk_mempool_put(g_spdk_msg_mempool, msg);
diff --git a/test/common/lib/test_env.c b/test/common/lib/test_env.c
index 44a3cf16a..9314f4948 100644
--- a/test/common/lib/test_env.c
+++ b/test/common/lib/test_env.c
@@ -358,7 +358,8 @@ spdk_ring_free(struct spdk_ring *ring)
 
 DEFINE_RETURN_MOCK(spdk_ring_enqueue, size_t);
 size_t
-spdk_ring_enqueue(struct spdk_ring *ring, void **objs, size_t count)
+spdk_ring_enqueue(struct spdk_ring *ring, void **objs, size_t count,
+		  size_t *free_space)
 {
 	struct spdk_ring_ele *ele;
 	size_t i;