On 2018/11/5 下午3:45, jiangyiwen wrote:
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 page everytime to compact with small
packet and big packet.
Signed-off-by: Yiwen Jiang <jiangyiwen@xxxxxxxxxx>
---
include/linux/virtio_vsock.h | 3 ++
net/vmw_vsock/virtio_transport.c | 72 +++++++++++++++++++++++++++++-----------
2 files changed, 56 insertions(+), 19 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..2040a9e 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -64,6 +64,7 @@ struct virtio_vsock {
struct virtio_vsock_event event_list[8];
u32 guest_cid;
+ bool mergeable;
};
static struct virtio_vsock *virtio_vsock_get(void)
@@ -256,6 +257,25 @@ static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
return 0;
}
+static int fill_mergeable_rx_buff(struct virtqueue *vq)
+{
+ void *page = NULL;
+ struct scatterlist sg;
+ int err;
+
+ page = (void *)get_zeroed_page(GFP_KERNEL);
Any reason to use zeroed page?
+ if (!page)
+ return -ENOMEM;
+
+ sg_init_one(&sg, page, PAGE_SIZE);
FYI, for virtio-net we have several optimizations for mergeable rx buffer:
- skb_page_frag_refill() which can use high order page and reduce the
stress of page allocator
- we don't use fixed buffer size, instead we use EWMA to estimate the
possible rx buffer size to avoid internal fragmentation
If we can try to reuse virtio-net driver, we will get those nice features.
Thanks
+
+ err = virtqueue_add_inbuf(vq, &sg, 1, page, GFP_KERNEL);
+ if (err < 0)
+ free_page((unsigned long) page);
+
+ return err;
+}
+
static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
{
int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
@@ -267,27 +287,33 @@ static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
vq = vsock->vqs[VSOCK_VQ_RX];
do {
- pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
- if (!pkt)
- break;
+ if (vsock->mergeable) {
+ ret = fill_mergeable_rx_buff(vq);
+ if (ret)
+ break;
+ } else {
+ pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+ if (!pkt)
+ break;
- pkt->buf = kmalloc(buf_len, GFP_KERNEL);
- if (!pkt->buf) {
- virtio_transport_free_pkt(pkt);
- break;
- }
+ 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);
- break;
+ 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);
+ break;
+ }
}
vsock->rx_buf_nr++;
} while (vq->num_free);
@@ -588,6 +614,9 @@ 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 +669,12 @@ 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)
+ free_page((unsigned long)(void *)pkt);
+ else
+ virtio_transport_free_pkt(pkt);
+ }
mutex_unlock(&vsock->rx_lock);
mutex_lock(&vsock->tx_lock);
@@ -683,6 +716,7 @@ 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 = {
