Re: [PATCH net-next 2/3] virtio_net: multiqueue support
From: Michael S. Tsirkin
Date: Tue Dec 04 2012 - 10:08:30 EST
On Tue, Dec 04, 2012 at 10:45:33PM +0800, Jason Wang wrote:
> On Tuesday, December 04, 2012 03:24:22 PM Michael S. Tsirkin wrote:
> > I found some bugs, see below.
> > Also some style nitpicking, this is not mandatory to address.
>
> Thanks for the reviewing.
> >
> > On Tue, Dec 04, 2012 at 07:07:57PM +0800, Jason Wang wrote:
> > > This addes multiqueue support to virtio_net driver. In multiple queue
> > > modes, the driver expects the number of queue paris is equal to the
> > > number of vcpus. To eliminate the contention bettwen vcpus and
> > > virtqueues, per-cpu virtqueue pairs
> > > were implemented through:
> > Lots of typos above - try running ispell on it :)
> >
>
> Sure.
> > > - select the txq based on the smp processor id.
> > > - smp affinity hint were set to the vcpu that owns the queue pairs.
> > >
> > > Signed-off-by: Krishna Kumar <krkumar2@xxxxxxxxxx>
> > > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > > ---
> > >
> > > drivers/net/virtio_net.c | 472
> > > ++++++++++++++++++++++++++++++--------- include/uapi/linux/virtio_net.h
> > > | 16 ++
> > > 2 files changed, 385 insertions(+), 103 deletions(-)
> > >
> > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > index 266f712..912f5b2 100644
> > > --- a/drivers/net/virtio_net.c
> > > +++ b/drivers/net/virtio_net.c
> > > @@ -81,16 +81,25 @@ struct virtnet_info {
> > >
> > > struct virtio_device *vdev;
> > > struct virtqueue *cvq;
> > > struct net_device *dev;
> > >
> > > - struct send_queue sq;
> > > - struct receive_queue rq;
> > > + struct send_queue *sq;
> > > + struct receive_queue *rq;
> > >
> > > unsigned int status;
> > >
> > > + /* Max # of queue pairs supported by the device */
> > > + u16 max_queue_pairs;
> > > +
> > > + /* # of queue pairs currently used by the driver */
> > > + u16 curr_queue_pairs;
> > > +
> > >
> > > /* I like... big packets and I cannot lie! */
> > > bool big_packets;
> > >
> > > /* Host will merge rx buffers for big packets (shake it! shake it!) */
> > > bool mergeable_rx_bufs;
> > >
> > > + /* Has control virtqueue */
> > > + bool has_cvq;
> > > +
> > >
> > > /* enable config space updates */
> > > bool config_enable;
> > >
> > > @@ -125,6 +134,32 @@ struct padded_vnet_hdr {
> > >
> > > char padding[6];
> > >
> > > };
> > >
> > > +static const struct ethtool_ops virtnet_ethtool_ops;
> > > +
> > > +
> > > +/* Converting between virtqueue no. and kernel tx/rx queue no.
> > > + * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
> > > + */
> > > +static int vq2txq(struct virtqueue *vq)
> > > +{
> > > + return (virtqueue_get_queue_index(vq) - 1) / 2;
> > > +}
> > > +
> > > +static int txq2vq(int txq)
> > > +{
> > > + return txq * 2 + 1;
> > > +}
> > > +
> > > +static int vq2rxq(struct virtqueue *vq)
> > > +{
> > > + return virtqueue_get_queue_index(vq) / 2;
> > > +}
> > > +
> > > +static int rxq2vq(int rxq)
> > > +{
> > > + return rxq * 2;
> > > +}
> > > +
> > >
> > > static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
> > > {
> > >
> > > return (struct skb_vnet_hdr *)skb->cb;
> > >
> > > @@ -165,7 +200,7 @@ static void skb_xmit_done(struct virtqueue *vq)
> > >
> > > virtqueue_disable_cb(vq);
> > >
> > > /* We were probably waiting for more output buffers. */
> > >
> > > - netif_wake_queue(vi->dev);
> > > + netif_wake_subqueue(vi->dev, vq2txq(vq));
> > >
> > > }
> > >
> > > static void set_skb_frag(struct sk_buff *skb, struct page *page,
> > >
> > > @@ -502,7 +537,7 @@ static bool try_fill_recv(struct receive_queue *rq,
> > > gfp_t gfp)>
> > > static void skb_recv_done(struct virtqueue *rvq)
> > > {
> > >
> > > struct virtnet_info *vi = rvq->vdev->priv;
> > >
> > > - struct receive_queue *rq = &vi->rq;
> > > + struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
> > >
> > > /* Schedule NAPI, Suppress further interrupts if successful. */
> > > if (napi_schedule_prep(&rq->napi)) {
> > >
> > > @@ -532,15 +567,21 @@ static void refill_work(struct work_struct *work)
> > >
> > > struct virtnet_info *vi =
> > >
> > > container_of(work, struct virtnet_info, refill.work);
> > >
> > > bool still_empty;
> > >
> > > + int i;
> > > +
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + struct receive_queue *rq = &vi->rq[i];
> > >
> > > - napi_disable(&vi->rq.napi);
> > > - still_empty = !try_fill_recv(&vi->rq, GFP_KERNEL);
> > > - virtnet_napi_enable(&vi->rq);
> > > + napi_disable(&rq->napi);
> > > + still_empty = !try_fill_recv(rq, GFP_KERNEL);
> > > + virtnet_napi_enable(rq);
> > >
> > > - /* In theory, this can happen: if we don't get any buffers in
> > > - * we will *never* try to fill again. */
> > > - if (still_empty)
> > > - schedule_delayed_work(&vi->refill, HZ/2);
> > > + /* In theory, this can happen: if we don't get any buffers in
> > > + * we will *never* try to fill again.
> > > + */
> > > + if (still_empty)
> > > + schedule_delayed_work(&vi->refill, HZ/2);
> > > + }
> > >
> > > }
> > >
> > > static int virtnet_poll(struct napi_struct *napi, int budget)
> > >
> > > @@ -650,7 +691,8 @@ static int xmit_skb(struct send_queue *sq, struct
> > > sk_buff *skb)>
> > > static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device
> > > *dev)
> > > {
> > >
> > > struct virtnet_info *vi = netdev_priv(dev);
> > >
> > > - struct send_queue *sq = &vi->sq;
> > > + int qnum = skb_get_queue_mapping(skb);
> > > + struct send_queue *sq = &vi->sq[qnum];
> > >
> > > int capacity;
> > >
> > > /* Free up any pending old buffers before queueing new ones. */
> > >
> > > @@ -664,13 +706,14 @@ static netdev_tx_t start_xmit(struct sk_buff *skb,
> > > struct net_device *dev)>
> > > if (likely(capacity == -ENOMEM)) {
> > >
> > > if (net_ratelimit())
> > >
> > > dev_warn(&dev->dev,
> > >
> > > - "TX queue failure: out of memory\n");
> > > + "TXQ (%d) failure: out of memory\n",
> > > + qnum);
> > >
> > > } else {
> > >
> > > dev->stats.tx_fifo_errors++;
> > > if (net_ratelimit())
> > >
> > > dev_warn(&dev->dev,
> > >
> > > - "Unexpected TX queue failure: %d\n",
> > > - capacity);
> > > + "Unexpected TXQ (%d) failure: %d\n",
> > > + qnum, capacity);
> > >
> > > }
> > > dev->stats.tx_dropped++;
> > > kfree_skb(skb);
> > >
> > > @@ -685,12 +728,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb,
> > > struct net_device *dev)>
> > > /* Apparently nice girls don't return TX_BUSY; stop the queue
> > >
> > > * before it gets out of hand. Naturally, this wastes entries. */
> > >
> > > if (capacity < 2+MAX_SKB_FRAGS) {
> > >
> > > - netif_stop_queue(dev);
> > > + netif_stop_subqueue(dev, qnum);
> > >
> > > if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
> > >
> > > /* More just got used, free them then recheck. */
> > > capacity += free_old_xmit_skbs(sq);
> > > if (capacity >= 2+MAX_SKB_FRAGS) {
> > >
> > > - netif_start_queue(dev);
> > > + netif_start_subqueue(dev, qnum);
> > >
> > > virtqueue_disable_cb(sq->vq);
> > >
> > > }
> > >
> > > }
> > >
> > > @@ -758,23 +801,13 @@ static struct rtnl_link_stats64
> > > *virtnet_stats(struct net_device *dev,>
> > > static void virtnet_netpoll(struct net_device *dev)
> > > {
> > >
> > > struct virtnet_info *vi = netdev_priv(dev);
> > >
> > > + int i;
> > >
> > > - napi_schedule(&vi->rq.napi);
> > > + for (i = 0; i < vi->curr_queue_pairs; i++)
> > > + napi_schedule(&vi->rq[i].napi);
> > >
> > > }
> > > #endif
> > >
> > > -static int virtnet_open(struct net_device *dev)
> > > -{
> > > - struct virtnet_info *vi = netdev_priv(dev);
> > > -
> > > - /* Make sure we have some buffers: if oom use wq. */
> > > - if (!try_fill_recv(&vi->rq, GFP_KERNEL))
> > > - schedule_delayed_work(&vi->refill, 0);
> > > -
> > > - virtnet_napi_enable(&vi->rq);
> > > - return 0;
> > > -}
> > > -
> > >
> > > /*
> > >
> > > * Send command via the control virtqueue and check status. Commands
> > > * supported by the hypervisor, as indicated by feature bits, should
> > >
> > > @@ -830,13 +863,51 @@ static void virtnet_ack_link_announce(struct
> > > virtnet_info *vi)>
> > > rtnl_unlock();
> > >
> > > }
> > >
> > > +/* Caller check the support of cvq and multiqueue. */
> > > +static int virtnet_set_queues(struct virtnet_info *vi)
> > > +{
> > > + struct scatterlist sg;
> > > + struct virtio_net_ctrl_rfs s;
> > > + struct net_device *dev = vi->dev;
> > > +
> > > + s.virtqueue_pairs = vi->curr_queue_pairs;
> > > + sg_init_one(&sg, &s, sizeof(s));
> > > +
> > > + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RFS,
> > > + VIRTIO_NET_CTRL_RFS_VQ_PAIRS_SET, &sg, 1, 0)){
> > > + dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
> > > + vi->curr_queue_pairs);
> > > + return -EINVAL;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int virtnet_open(struct net_device *dev)
> >
> > Why move this here? diff will be smaller if you don't.
>
> Ok, will move it back.
> >
> > > +{
> > > + struct virtnet_info *vi = netdev_priv(dev);
> > > + int i;
> > > +
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + /* Make sure we have some buffers: if oom use wq. */
> > > + if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
> > > + schedule_delayed_work(&vi->refill, 0);
> > > + virtnet_napi_enable(&vi->rq[i]);
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > >
> > > static int virtnet_close(struct net_device *dev)
> > > {
> > >
> > > struct virtnet_info *vi = netdev_priv(dev);
> > >
> > > + int i;
> > >
> > > /* Make sure refill_work doesn't re-enable napi! */
> > > cancel_delayed_work_sync(&vi->refill);
> > >
> > > - napi_disable(&vi->rq.napi);
> > > +
> > > + for (i = 0; i < vi->max_queue_pairs; i++)
> > > + napi_disable(&vi->rq[i].napi);
> > >
> > > return 0;
> > >
> > > }
> > >
> > > @@ -948,8 +1019,8 @@ static void virtnet_get_ringparam(struct net_device
> > > *dev,>
> > > {
> > >
> > > struct virtnet_info *vi = netdev_priv(dev);
> > >
> > > - ring->rx_max_pending = virtqueue_get_vring_size(vi->rq.vq);
> > > - ring->tx_max_pending = virtqueue_get_vring_size(vi->sq.vq);
> > > + ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
> > > + ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
> > >
> > > ring->rx_pending = ring->rx_max_pending;
> > > ring->tx_pending = ring->tx_max_pending;
> > >
> > > }
> > >
> > > @@ -967,12 +1038,6 @@ static void virtnet_get_drvinfo(struct net_device
> > > *dev,>
> > > }
> > >
> > > -static const struct ethtool_ops virtnet_ethtool_ops = {
> > > - .get_drvinfo = virtnet_get_drvinfo,
> > > - .get_link = ethtool_op_get_link,
> > > - .get_ringparam = virtnet_get_ringparam,
> > > -};
> > > -
> > >
> > > #define MIN_MTU 68
> > > #define MAX_MTU 65535
> > >
> > > @@ -984,6 +1049,21 @@ static int virtnet_change_mtu(struct net_device
> > > *dev, int new_mtu)>
> > > return 0;
> > >
> > > }
> > >
> > > +/* To avoid contending a lock hold by a vcpu who would exit to host,
> > > select the + * txq based on the processor id.
> > > + * TODO: handle cpu hotplug.
> > > + */
> > > +static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff
> > > *skb) +{
> > > + int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) :
> > > + smp_processor_id();
> > > +
> > > + while (unlikely(txq >= dev->real_num_tx_queues))
> > > + txq -= dev->real_num_tx_queues;
> > > +
> > > + return txq;
> > > +}
> > > +
> > >
> > > static const struct net_device_ops virtnet_netdev = {
> > >
> > > .ndo_open = virtnet_open,
> > > .ndo_stop = virtnet_close,
> > >
> > > @@ -995,6 +1075,7 @@ static const struct net_device_ops virtnet_netdev = {
> > >
> > > .ndo_get_stats64 = virtnet_stats,
> > > .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
> > > .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
> > >
> > > + .ndo_select_queue = virtnet_select_queue,
> > >
> > > #ifdef CONFIG_NET_POLL_CONTROLLER
> > >
> > > .ndo_poll_controller = virtnet_netpoll,
> > >
> > > #endif
> > >
> > > @@ -1030,10 +1111,10 @@ static void virtnet_config_changed_work(struct
> > > work_struct *work)>
> > > if (vi->status & VIRTIO_NET_S_LINK_UP) {
> > >
> > > netif_carrier_on(vi->dev);
> > >
> > > - netif_wake_queue(vi->dev);
> > > + netif_tx_wake_all_queues(vi->dev);
> > >
> > > } else {
> > >
> > > netif_carrier_off(vi->dev);
> > >
> > > - netif_stop_queue(vi->dev);
> > > + netif_tx_stop_all_queues(vi->dev);
> > >
> > > }
> > >
> > > done:
> > > mutex_unlock(&vi->config_lock);
> > >
> > > @@ -1046,41 +1127,219 @@ static void virtnet_config_changed(struct
> > > virtio_device *vdev)>
> > > schedule_work(&vi->config_work);
> > >
> > > }
> > >
> > > -static int init_vqs(struct virtnet_info *vi)
> > > +static void free_receive_bufs(struct virtnet_info *vi)
> > >
> > > {
> > >
> > > - struct virtqueue *vqs[3];
> > > - vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
> > > - const char *names[] = { "input", "output", "control" };
> > > - int nvqs, err;
> > > + int i;
> > >
> > > - /* We expect two virtqueues, receive then send,
> > > - * and optionally control. */
> > > - nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + while (vi->rq[i].pages)
> > > + __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
> > > + }
> > > +}
> > >
> > > - err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names);
> > > - if (err)
> > > - return err;
> > > +/* Free memory allocated for send and receive queues */
> > > +static void virtnet_free_queues(struct virtnet_info *vi)
> >
> > I think it's cleaner to open-code this, this way
> > during error handling you can have:
> >
> > kfree(vi->rq);
> > err_rq:
> > kfree(vi->sq);
> > err_sq:
> >
> > without tricks like malloc them both then goto end.
>
> Ok.
> >
> > > +{
> > > + kfree(vi->rq);
> > > + vi->rq = NULL;
> > > + kfree(vi->sq);
> > > + vi->sq = NULL;
> >
> > I think = NULL is not needed - we never call this twice.
>
> Sure, will remove it.
> >
> > > +}
> > > +
> > > +static void free_unused_bufs(struct virtnet_info *vi)
> > > +{
> > > + void *buf;
> > > + int i;
> > > +
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + struct virtqueue *vq = vi->sq[i].vq;
> > > + while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
> > > + dev_kfree_skb(buf);
> > > + }
> > > +
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + struct virtqueue *vq = vi->rq[i].vq;
> > > +
> > > + while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
> > > + if (vi->mergeable_rx_bufs || vi->big_packets)
> > > + give_pages(&vi->rq[i], buf);
> > > + else
> > > + dev_kfree_skb(buf);
> > > + --vi->rq[i].num;
> > > + }
> > > + BUG_ON(vi->rq[i].num != 0);
> > > + }
> > > +}
> > > +
> > > +static void virtnet_set_affinity(struct virtnet_info *vi, bool set)
> > > +{
> > > + int i;
> > > +
> > > + /* Don't set the affinity hint when in single queue mode or we have too
> > > + * much online cpus.
> > > + */
> >
> > Pls remove this comment, or replace with one explaining
> > the motivation for this logic.
>
> Will replace with the motivation.
> >
> > > + if (vi->curr_queue_pairs == 1 ||
> > > + vi->max_queue_pairs > num_online_cpus())
> >
> > If we have less it's not a good idea either, is it?
> > So check vi->max_queue_pairs != num_online_cpus().
>
> Ok.
> >
> > > + set = false;
> >
> > This will overwrite affinity if it was set by userspace.
> > Just
> > if (set)
> > return;
> > will not have this problem.
>
> But we need handle the situtaiton when switch back to sq from mq mode.
> Otherwise we may still get the affinity hint used in mq.
> This kind of overwrite
> is unavoidable or is there some method to detect whether userspac write
> something new?
If we didn't set the affinity originally we should not overwrite it.
I think this means we need a flag that tells us that
virtio set the affinity.
> >
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + int cpu = set ? i : -1;
> > > + virtqueue_set_affinity(vi->rq[i].vq, cpu);
> > > + virtqueue_set_affinity(vi->sq[i].vq, cpu);
> > > + }
> > > +}
> > > +
> > > +static void virtnet_del_vqs(struct virtnet_info *vi)
> >
> > It might be a good idea to add this function in previous
> > patch.
>
> Yes, good suggetion.
> >
> > > +{
> > > + struct virtio_device *vdev = vi->vdev;
> > > +
> > > + virtnet_set_affinity(vi, false);
> > > +
> > > + vdev->config->del_vqs(vdev);
> > >
> > > - vi->rq.vq = vqs[0];
> > > - vi->sq.vq = vqs[1];
> > > + virtnet_free_queues(vi);
> > > +}
> > >
> > > - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
> > > - vi->cvq = vqs[2];
> > > +static int virtnet_find_vqs(struct virtnet_info *vi)
> > > +{
> > > + vq_callback_t **callbacks;
> > > + struct virtqueue **vqs;
> > > + int ret = -ENOMEM;
> > > + int i, total_vqs;
> > > + char **names;
> > > +
> > > + /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followd by
> >
> > followed
> >
>
> Ok, will correct it.
> > > + * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
> > > + * possible control vq.
> > > + */
> > > + total_vqs = vi->max_queue_pairs * 2 +
> > > + virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
> > > +
> > > + /* Allocate space for find_vqs parameters */
> > > + vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
> > > + callbacks = kzalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
> > > + if (!vqs || !callbacks)
> > > + goto err_mem;
> > > + names = kzalloc(total_vqs * sizeof(*names), GFP_KERNEL);
> >
> > Why kzalloc? You seem to fill in all of it. Pls just use kmalloc
> > and initialize fields.
> >
>
> Right.
> > > + if (!names)
> > > + goto err_mem;
> >
> > Since you have separate goto here it's more consistent
> > to use a separate label and two if tests above.
> >
>
> Sure.
> > > +
> > > + /* Parameters for control virtqueue, if any */
> > > + if (vi->has_cvq) {
> > > + callbacks[total_vqs - 1] = NULL;
> > > + names[total_vqs - 1] = kasprintf(GFP_KERNEL, "control");
> > > + }
> > >
> > > + /* Allocate/initialize parameters for send/receive virtqueues */
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + callbacks[rxq2vq(i)] = skb_recv_done;
> > > + callbacks[txq2vq(i)] = skb_xmit_done;
> > > + names[rxq2vq(i)] = kasprintf(GFP_KERNEL, "input.%d", i);
> > > + names[txq2vq(i)] = kasprintf(GFP_KERNEL, "output.%d", i);
> > > + }
> >
> > We would need to check kasprintf return value.
>
> Looks like a better method is to make the name as a memeber of receive_queue
> and send_queue, and use sprintf here.
> > Also if you allocate names from slab we'll need to free them
> > later.
>
> Then it could be freed when the send_queue and receive_queue is freed.
> > It's probably easier to just use fixed names for now -
> > it's not like the index is really useful.
>
> Looks useful for debugging e.g. check whether the irq distribution is as
> expected.
Well it doesn't really matter which one goes where, right?
As long as interrupts are distributed well.
> >
> > > +
> > > + ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
> > > + (const char **)names);
> >
> > Please avoid casts, use a proper type for names.
>
> I'm consider we need a minor change in this api, we need allocate the names
> dynamically which could not be a const char **.
I don't see why. Any use that allocates on the fly as
you did would leak memory. Any use like you suggest
e.g. allocating as part of send/receive structure
would be fine.
> >
> > > + if (ret)
> > > + goto err_names;
> > > +
> > > + if (vi->has_cvq) {
> > > + vi->cvq = vqs[total_vqs - 1];
> > >
> > > if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
> > >
> > > vi->dev->features |= NETIF_F_HW_VLAN_FILTER;
> > >
> > > }
> > >
> > > +
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + vi->rq[i].vq = vqs[rxq2vq(i)];
> > > + vi->sq[i].vq = vqs[txq2vq(i)];
> > > + }
> > > +
> > > + kfree(callbacks);
> > > + kfree(vqs);
> >
> > Who frees names if there's no error?
> >
>
> The virtio core does not copy the name, so it need this and only used for
> debugging if I'm reading the code correctly.
No, virtio core does not free either individual vq name or the names
array passed in. So this leaks memory.
> > > +
> > > + return 0;
> > > +
> > > +err_names:
> > > + for (i = 0; i < total_vqs * 2; i++)
> >
> > Why * 2?
> > This looks like a bug.
>
> Yes, it's a bug.
> >
> > > + kfree(names[i]);
> > > + kfree(names);
> > > +
> > > +err_mem:
> > > + kfree(callbacks);
> > > + kfree(vqs);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +static int virtnet_alloc_queues(struct virtnet_info *vi)
> > > +{
> > > + int i;
> > > +
> > > + vi->sq = kzalloc(sizeof(vi->sq[0]) * vi->max_queue_pairs, GFP_KERNEL);
> > > + vi->rq = kzalloc(sizeof(vi->rq[0]) * vi->max_queue_pairs, GFP_KERNEL);
> >
> > While equivalent, *vi->rq is clearer IMHO.
>
> Ok.
> >
> > > + if (!vi->rq || !vi->sq)
> > > + goto err;
> > > +
> > > + INIT_DELAYED_WORK(&vi->refill, refill_work);
> > > + /* setup initial receive and send queue parameters */
> >
> > Pls remove this comment, it's confuses more than it clarifies.
>
> Sure.
> >
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + vi->rq[i].pages = NULL;
> > > + netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
> > > + napi_weight);
> > > +
> > > + sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
> > > + sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
> > > + }
> > > +
> > > +
> >
> > Extra empty line.
> >
>
> Will remove this line.
> > > + return 0;
> > > +
> > > +err:
> > > + virtnet_free_queues(vi);
> > > + return -ENOMEM;
> > > +}
> > > +
> > > +static int init_vqs(struct virtnet_info *vi)
> > > +{
> > > + int ret;
> > > +
> > > + /* Allocate send & receive queues */
> > > + ret = virtnet_alloc_queues(vi);
> > > + if (ret)
> > > + goto err;
> > > +
> > > + ret = virtnet_find_vqs(vi);
> > > + if (ret)
> > > + goto err_free;
> > > +
> > > + virtnet_set_affinity(vi, true);
> > >
> > > return 0;
> > >
> > > +
> > > +err_free:
> > > + virtnet_free_queues(vi);
> > > +err:
> > > + return ret;
> > >
> > > }
> > >
> > > static int virtnet_probe(struct virtio_device *vdev)
> > > {
> > >
> > > - int err;
> > > + int i, err;
> > >
> > > struct net_device *dev;
> > > struct virtnet_info *vi;
> > >
> > > + u16 max_queue_pairs;
> > > +
> > > + /* Find if host supports multiqueue virtio_net device */
> > > + err = virtio_config_val(vdev, VIRTIO_NET_F_RFS,
> > > + offsetof(struct virtio_net_config,
> > > + max_virtqueue_pairs), &max_queue_pairs);
> > > +
> > > + /* We need at least 2 queue's */
> > > + if (err || max_queue_pairs < VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MIN ||
> > > + max_queue_pairs > VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MAX)
> >
> > Check has_cvq as well.
> >
>
> Sure.
> > > + max_queue_pairs = 1;
> > >
> > > /* Allocate ourselves a network device with room for our info */
> > >
> > > - dev = alloc_etherdev(sizeof(struct virtnet_info));
> > > + dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
> > >
> > > if (!dev)
> > >
> > > return -ENOMEM;
> > >
> > > @@ -1127,22 +1386,17 @@ static int virtnet_probe(struct virtio_device
> > > *vdev)>
> > > /* Set up our device-specific information */
> > > vi = netdev_priv(dev);
> > >
> > > - netif_napi_add(dev, &vi->rq.napi, virtnet_poll, napi_weight);
> > >
> > > vi->dev = dev;
> > > vi->vdev = vdev;
> > > vdev->priv = vi;
> > >
> > > - vi->rq.pages = NULL;
> > >
> > > vi->stats = alloc_percpu(struct virtnet_stats);
> > > err = -ENOMEM;
> > > if (vi->stats == NULL)
> > >
> > > goto free;
> > >
> > > - INIT_DELAYED_WORK(&vi->refill, refill_work);
> > >
> > > mutex_init(&vi->config_lock);
> > > vi->config_enable = true;
> > > INIT_WORK(&vi->config_work, virtnet_config_changed_work);
> > >
> > > - sg_init_table(vi->rq.sg, ARRAY_SIZE(vi->rq.sg));
> > > - sg_init_table(vi->sq.sg, ARRAY_SIZE(vi->sq.sg));
> > >
> > > /* If we can receive ANY GSO packets, we must allocate large ones. */
> > > if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
> > >
> > > @@ -1153,10 +1407,21 @@ static int virtnet_probe(struct virtio_device
> > > *vdev)>
> > > if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
> > >
> > > vi->mergeable_rx_bufs = true;
> > >
> > > + if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
> > > + vi->has_cvq = true;
> > > +
> > > + /* Use single tx/rx queue pair as default */
> > > + vi->curr_queue_pairs = 1;
> > > + vi->max_queue_pairs = max_queue_pairs;
> > > +
> > > + /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
> > >
> > > err = init_vqs(vi);
> > > if (err)
> > >
> > > goto free_stats;
> > >
> > > + netif_set_real_num_tx_queues(dev, 1);
> > > + netif_set_real_num_rx_queues(dev, 1);
> > > +
> > >
> > > err = register_netdev(dev);
> > > if (err) {
> > >
> > > pr_debug("virtio_net: registering device failed\n");
> > >
> > > @@ -1164,12 +1429,15 @@ static int virtnet_probe(struct virtio_device
> > > *vdev)>
> > > }
> > >
> > > /* Last of all, set up some receive buffers. */
> > >
> > > - try_fill_recv(&vi->rq, GFP_KERNEL);
> > > -
> > > - /* If we didn't even get one input buffer, we're useless. */
> > > - if (vi->rq.num == 0) {
> > > - err = -ENOMEM;
> > > - goto unregister;
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + try_fill_recv(&vi->rq[i], GFP_KERNEL);
> > > +
> > > + /* If we didn't even get one input buffer, we're useless. */
> > > + if (vi->rq[i].num == 0) {
> > > + free_unused_bufs(vi);
> > > + err = -ENOMEM;
> > > + goto free_recv_bufs;
> > > + }
> > >
> > > }
> > >
> > > /* Assume link up if device can't report link status,
> > >
> > > @@ -1182,13 +1450,19 @@ static int virtnet_probe(struct virtio_device
> > > *vdev)>
> > > netif_carrier_on(dev);
> > >
> > > }
> > >
> > > - pr_debug("virtnet: registered device %s\n", dev->name);
> > > + pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
> > > + dev->name, max_queue_pairs);
> > > +
> > >
> > > return 0;
> > >
> > > -unregister:
> > > +free_recv_bufs:
> > > + free_receive_bufs(vi);
> > >
> > > unregister_netdev(dev);
> > >
> > > +
> > >
> > > free_vqs:
> > > - vdev->config->del_vqs(vdev);
> > > + cancel_delayed_work_sync(&vi->refill);
> > > + virtnet_del_vqs(vi);
> > > +
> > >
> > > free_stats:
> > > free_percpu(vi->stats);
> > >
> > > free:
> > > @@ -1196,28 +1470,6 @@ free:
> > > return err;
> > >
> > > }
> > >
> > > -static void free_unused_bufs(struct virtnet_info *vi)
> > > -{
> > > - void *buf;
> > > - while (1) {
> > > - buf = virtqueue_detach_unused_buf(vi->sq.vq);
> > > - if (!buf)
> > > - break;
> > > - dev_kfree_skb(buf);
> > > - }
> > > - while (1) {
> > > - buf = virtqueue_detach_unused_buf(vi->rq.vq);
> > > - if (!buf)
> > > - break;
> > > - if (vi->mergeable_rx_bufs || vi->big_packets)
> > > - give_pages(&vi->rq, buf);
> > > - else
> > > - dev_kfree_skb(buf);
> > > - --vi->rq.num;
> > > - }
> > > - BUG_ON(vi->rq.num != 0);
> > > -}
> > > -
> > >
> > > static void remove_vq_common(struct virtnet_info *vi)
> > > {
> > >
> > > vi->vdev->config->reset(vi->vdev);
> > >
> > > @@ -1225,10 +1477,9 @@ static void remove_vq_common(struct virtnet_info
> > > *vi)>
> > > /* Free unused buffers in both send and recv, if any. */
> > > free_unused_bufs(vi);
> > >
> > > - vi->vdev->config->del_vqs(vi->vdev);
> > > + free_receive_bufs(vi);
> > >
> > > - while (vi->rq.pages)
> > > - __free_pages(get_a_page(&vi->rq, GFP_KERNEL), 0);
> > > + virtnet_del_vqs(vi);
> > >
> > > }
> > >
> > > static void __devexit virtnet_remove(struct virtio_device *vdev)
> > >
> > > @@ -1254,6 +1505,7 @@ static void __devexit virtnet_remove(struct
> > > virtio_device *vdev)>
> > > static int virtnet_freeze(struct virtio_device *vdev)
> > > {
> > >
> > > struct virtnet_info *vi = vdev->priv;
> > >
> > > + int i;
> > >
> > > /* Prevent config work handler from accessing the device */
> > > mutex_lock(&vi->config_lock);
> > >
> > > @@ -1264,7 +1516,10 @@ static int virtnet_freeze(struct virtio_device
> > > *vdev)>
> > > cancel_delayed_work_sync(&vi->refill);
> > >
> > > if (netif_running(vi->dev))
> > >
> > > - napi_disable(&vi->rq.napi);
> > > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > > + napi_disable(&vi->rq[i].napi);
> > > + netif_napi_del(&vi->rq[i].napi);
> > > + }
> > >
> > > remove_vq_common(vi);
> > >
> > > @@ -1276,24 +1531,29 @@ static int virtnet_freeze(struct virtio_device
> > > *vdev)>
> > > static int virtnet_restore(struct virtio_device *vdev)
> > > {
> > >
> > > struct virtnet_info *vi = vdev->priv;
> > >
> > > - int err;
> > > + int err, i;
> > >
> > > err = init_vqs(vi);
> > > if (err)
> > >
> > > return err;
> > >
> > > if (netif_running(vi->dev))
> > >
> > > - virtnet_napi_enable(&vi->rq);
> > > + for (i = 0; i < vi->max_queue_pairs; i++)
> > > + virtnet_napi_enable(&vi->rq[i]);
> > >
> > > netif_device_attach(vi->dev);
> > >
> > > - if (!try_fill_recv(&vi->rq, GFP_KERNEL))
> > > - schedule_delayed_work(&vi->refill, 0);
> > > + for (i = 0; i < vi->max_queue_pairs; i++)
> > > + if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
> > > + schedule_delayed_work(&vi->refill, 0);
> > >
> > > mutex_lock(&vi->config_lock);
> > > vi->config_enable = true;
> > > mutex_unlock(&vi->config_lock);
> > >
> > > + if (vi->has_cvq && virtio_has_feature(vi->vdev, VIRTIO_NET_F_RFS))
> > > + virtnet_set_queues(vi);
> > > +
> >
> > I think it's easier to test
> > if (curr_queue_pairs == max_queue_pairs)
> > within virtnet_set_queues and make it
> > a NOP if so.
>
> Still need to send the command during restore since we reset the device during
> freezing.
Then maybe check vi->has_cvq && virtio_has_feature(vi->vdev,
VIRTIO_NET_F_RFS) in there?
> >
> > > return 0;
> > >
> > > }
> > > #endif
> > >
> > > @@ -1311,7 +1571,7 @@ static unsigned int features[] = {
> > >
> > > VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
> > > VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
> > > VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
> > >
> > > - VIRTIO_NET_F_GUEST_ANNOUNCE,
> > > + VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_RFS,
> > >
> > > };
> > >
> > > static struct virtio_driver virtio_net_driver = {
> > >
> > > @@ -1329,6 +1589,12 @@ static struct virtio_driver virtio_net_driver = {
> > >
> > > #endif
> > > };
> > >
> > > +static const struct ethtool_ops virtnet_ethtool_ops = {
> > > + .get_drvinfo = virtnet_get_drvinfo,
> > > + .get_link = ethtool_op_get_link,
> > > + .get_ringparam = virtnet_get_ringparam,
> > > +};
> > > +
> > >
> > > static int __init init(void)
> > > {
> > >
> > > return register_virtio_driver(&virtio_net_driver);
> > >
> > > diff --git a/include/uapi/linux/virtio_net.h
> > > b/include/uapi/linux/virtio_net.h index 2470f54..6056cec 100644
> > > --- a/include/uapi/linux/virtio_net.h
> > > +++ b/include/uapi/linux/virtio_net.h
> > > @@ -51,6 +51,7 @@
> > >
> > > #define VIRTIO_NET_F_CTRL_RX_EXTRA 20 /* Extra RX mode control support
> */
> > > #define VIRTIO_NET_F_GUEST_ANNOUNCE 21 /* Guest can announce device on
> > > the
> > >
> > > * network */
> > >
> > > +#define VIRTIO_NET_F_RFS 22 /* Device supports multiple TXQ/RXQ */
> >
> > Should be
> > /* Device supports Receive Flow Steering. */
>
> Ok.
> >
> > > #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
> > > #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */
> > >
> > > @@ -60,6 +61,8 @@ struct virtio_net_config {
> > >
> > > __u8 mac[6];
> > > /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
> > > __u16 status;
> > >
> > > + /* Total number of RX/TX queues */
> >
> > Better comment:
> > /* Maximum number of each of transmit and receive queues;
> > * see VIRTIO_NET_F_RFS and VIRTIO_NET_CTRL_RFS.
> > * Legal values are between 1 and 0x8000
> > */
>
> Sure.
> >
> > > + __u16 max_virtqueue_pairs;
> > >
> > > } __attribute__((packed));
> > >
> > > /* This is the first element of the scatter-gather list. If you don't
> > >
> > > @@ -166,4 +169,17 @@ struct virtio_net_ctrl_mac {
> > >
> > > #define VIRTIO_NET_CTRL_ANNOUNCE 3
> > >
> > > #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0
> > >
> > > +/*
> > > + * Control multiqueue
> >
> > Here's a better comment:
> >
> > Control Receive Flow Steering
> >
> > The command VIRTIO_NET_CTRL_RFS_VQ_PAIRS_SET
> > enables Receive Flow Steering, specifying the number of the transmit and
> > receive queues that will be used.
> > After the command is consumed and acked by the device,
> > the device will not steer new packets on receive virtqueues
> > other than specified nor read from transmit virtqueues other than
> > specified. Accordingly, driver should not transmit new packets
> > on virtqueues other than specified.
> >
>
> Sure, thanks for the this reminding.
> > > + *
> >
> > Remove this empty line.
>
> Ok.
> >
> > > + */
> > > +struct virtio_net_ctrl_rfs {
> >
> > /* Number of each of transmit and receive queues to use;
> > * Legal values are between 1 and max_virtqueue_pairs
> > */
> >
> > > + u16 virtqueue_pairs;
> > > +};
> > > +
> > > +#define VIRTIO_NET_CTRL_RFS 4
> > > + #define VIRTIO_NET_CTRL_RFS_VQ_PAIRS_SET 0
> >
> > /* Value range for max_virtqueue_pairsfor and virtqueue_pairs above */
> >
> > > + #define VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MIN 1
> > > + #define VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MAX 0x8000
> > > +
> > >
> > > #endif /* _LINUX_VIRTIO_NET_H */
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
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