In driver probing, if virtio has VIRTIO_VSOCK_F_MRG_RXBUF feature,
it will fill mergeable rx buffer, support for host send mergeable
rx buffer. It will fill a fixed size(PAGE_SIZE) everytime to
compact with small packet and big packet.
In addition, it also add one optimizations copied from virtio-net.c.
- Skb_page_frag_refill() which can use high order page and
reduce the stress of page allocator.
Signed-off-by: Yiwen Jiang <jiangyiwen@xxxxxxxxxx>
---
include/linux/virtio_vsock.h | 3 ++
net/vmw_vsock/virtio_transport.c | 112 +++++++++++++++++++++++++++++++--------
2 files changed, 92 insertions(+), 23 deletions(-)
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index e223e26..bf84418 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -14,6 +14,9 @@
#define VIRTIO_VSOCK_MAX_BUF_SIZE 0xFFFFFFFFUL
#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE (1024 * 64)
+/* Virtio-vsock feature */
+#define VIRTIO_VSOCK_F_MRG_RXBUF 0 /* Host can merge receive buffers. */
+
enum {
VSOCK_VQ_RX = 0, /* for host to guest data */
VSOCK_VQ_TX = 1, /* for guest to host data */
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 5d3cce9..c4a465c 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -64,6 +64,11 @@ struct virtio_vsock {
struct virtio_vsock_event event_list[8];
u32 guest_cid;
+
+ /* As mergeable rx buffer flag */
+ bool mergeable;
+ /* Page frag for packet buffer allocation. */
+ struct page_frag alloc_frag;
};
static struct virtio_vsock *virtio_vsock_get(void)
@@ -256,39 +261,89 @@ static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
return 0;
}
-static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
+/* This segment of codes are copied from virtio-net.c */
+static int fill_mergeable_rx_buff(struct virtio_vsock *vsock,
+ struct virtqueue *vq)
+{
+ struct page_frag *alloc_frag = &vsock->alloc_frag;
+ struct scatterlist sg;
+ /* Currently we don't use ewma len, use PAGE_SIZE instead, because too
+ * small size can't fill one full packet, sadly we only 128 vq num now.
+ */
+ unsigned int len = PAGE_SIZE, hole;
+ void *buf;
+ int err;
+
+ if (unlikely(!skb_page_frag_refill(len, alloc_frag, GFP_KERNEL)))
+ return -ENOMEM;
+
+ buf = (void *)page_address(alloc_frag->page) + alloc_frag->offset;
+ get_page(alloc_frag->page);
+ alloc_frag->offset += len;
+ hole = alloc_frag->size - alloc_frag->offset;
+ if (hole < len) {
+ /* To avoid internal fragmentation, if there is very likely not
+ * enough space for another buffer, add the remaining space to
+ * the current buffer.
+ */
+ len += hole;
+ alloc_frag->offset += hole;
+ }
+
+ sg_init_one(&sg, buf, len);
+ err = virtqueue_add_inbuf(vq, &sg, 1, buf, GFP_KERNEL);
+ if (err < 0)
+ put_page(virt_to_head_page(buf));
+
+ return err;
+}
+
+static int fill_old_rx_buff(struct virtqueue *vq)
{
int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
struct virtio_vsock_pkt *pkt;
struct scatterlist hdr, buf, *sgs[2];
- struct virtqueue *vq;
int ret;
- vq = vsock->vqs[VSOCK_VQ_RX];
+ pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+ if (!pkt)
+ return -ENOMEM;
- do {
- pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
- if (!pkt)
- break;
+ pkt->buf = kmalloc(buf_len, GFP_KERNEL);
+ if (!pkt->buf) {
+ virtio_transport_free_pkt(pkt);
+ return -ENOMEM;
+ }
- pkt->buf = kmalloc(buf_len, GFP_KERNEL);
- if (!pkt->buf) {
- virtio_transport_free_pkt(pkt);
- break;
- }
+ pkt->len = buf_len;
- pkt->len = buf_len;
+ sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
+ sgs[0] = &hdr;
- sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
- sgs[0] = &hdr;
+ sg_init_one(&buf, pkt->buf, buf_len);
+ sgs[1] = &buf;
+ ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
+ if (ret)
+ virtio_transport_free_pkt(pkt);
- sg_init_one(&buf, pkt->buf, buf_len);
- sgs[1] = &buf;
- ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
- if (ret) {
- virtio_transport_free_pkt(pkt);
+ return ret;
+}
+
+static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
+{
+ struct virtqueue *vq;
+ int ret;
+
+ vq = vsock->vqs[VSOCK_VQ_RX];
+
+ do {
+ if (vsock->mergeable)
+ ret = fill_mergeable_rx_buff(vsock, vq);
+ else
+ ret = fill_old_rx_buff(vq);
+ if (ret)
break;
- }
+
vsock->rx_buf_nr++;
} while (vq->num_free);
if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
@@ -588,6 +643,9 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
if (ret < 0)
goto out_vqs;
+ if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_MRG_RXBUF))
+ vsock->mergeable = true;
+
vsock->rx_buf_nr = 0;
vsock->rx_buf_max_nr = 0;
atomic_set(&vsock->queued_replies, 0);
@@ -640,8 +698,15 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
vdev->config->reset(vdev);
mutex_lock(&vsock->rx_lock);
- while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
- virtio_transport_free_pkt(pkt);
+ while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX]))) {
+ if (vsock->mergeable)
+ put_page(virt_to_head_page((void *)pkt));
+ else
+ virtio_transport_free_pkt(pkt);
+ }
+
+ if (vsock->alloc_frag.page)
+ put_page(vsock->alloc_frag.page);
mutex_unlock(&vsock->rx_lock);
mutex_lock(&vsock->tx_lock);
@@ -683,6 +748,7 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
};
static unsigned int features[] = {
+ VIRTIO_VSOCK_F_MRG_RXBUF,
};
static struct virtio_driver virtio_vsock_driver = {
--
1.8.3.1
