From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752777Ab2GTNkZ (ORCPT ); Fri, 20 Jul 2012 09:40:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39165 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751297Ab2GTNkW (ORCPT ); Fri, 20 Jul 2012 09:40:22 -0400 Date: Fri, 20 Jul 2012 16:40:14 +0300 From: "Michael S. Tsirkin" To: Jason Wang Cc: mashirle@us.ibm.com, krkumar2@in.ibm.com, habanero@linux.vnet.ibm.com, rusty@rustcorp.com.au, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, edumazet@google.com, tahm@linux.vnet.ibm.com, jwhan@filewood.snu.ac.kr, davem@davemloft.net, akong@redhat.com, kvm@vger.kernel.org, sri@us.ibm.com Subject: Re: [net-next RFC V5 4/5] virtio_net: multiqueue support Message-ID: <20120720134014.GD16550@redhat.com> References: <1341484194-8108-1-git-send-email-jasowang@redhat.com> <1341484194-8108-5-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1341484194-8108-5-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 05, 2012 at 06:29:53PM +0800, Jason Wang wrote: > This patch converts virtio_net to a multi queue device. After negotiated > VIRTIO_NET_F_MULTIQUEUE feature, the virtio device has many tx/rx queue pairs, > and driver could read the number from config space. > > The driver expects the number of rx/tx queue paris is equal to the number of > vcpus. To maximize the performance under this per-cpu rx/tx queue pairs, some > optimization were introduced: > > - Txq selection is based on the processor id in order to avoid contending a lock > whose owner may exits to host. > - Since the txq/txq were per-cpu, affinity hint were set to the cpu that owns > the queue pairs. > > Signed-off-by: Krishna Kumar > Signed-off-by: Jason Wang Overall fine. I think it is best to smash the following patch into this one, so that default behavior does not jump to mq then back. some comments below: mostly nits, and a minor bug. If you are worried the patch is too big, it can be split differently - rework to use send_queue/receive_queue structures, no functional changes. - add multiqueue but this is not a must. > --- > drivers/net/virtio_net.c | 645 ++++++++++++++++++++++++++++++------------- > include/linux/virtio_net.h | 2 + > 2 files changed, 452 insertions(+), 195 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 1db445b..7410187 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -26,6 +26,7 @@ > #include > #include > #include > +#include > > static int napi_weight = 128; > module_param(napi_weight, int, 0444); > @@ -41,6 +42,8 @@ module_param(gso, bool, 0444); > #define VIRTNET_SEND_COMMAND_SG_MAX 2 > #define VIRTNET_DRIVER_VERSION "1.0.0" > > +#define MAX_QUEUES 256 > + > struct virtnet_stats { > struct u64_stats_sync tx_syncp; > struct u64_stats_sync rx_syncp; Would be a bit better not to have artificial limits like that. Maybe allocate arrays at probe time, then we can take whatever the device gives us? > @@ -51,43 +54,69 @@ struct virtnet_stats { > u64 rx_packets; > }; > > -struct virtnet_info { > - struct virtio_device *vdev; > - struct virtqueue *rvq, *svq, *cvq; > - struct net_device *dev; > +/* Internal representation of a send virtqueue */ > +struct send_queue { > + /* Virtqueue associated with this send _queue */ > + struct virtqueue *vq; > + > + /* TX: fragments + linear part + virtio header */ > + struct scatterlist sg[MAX_SKB_FRAGS + 2]; > +}; > + > +/* Internal representation of a receive virtqueue */ > +struct receive_queue { > + /* Virtqueue associated with this receive_queue */ > + struct virtqueue *vq; > + > + /* Back pointer to the virtnet_info */ > + struct virtnet_info *vi; > + > struct napi_struct napi; > - unsigned int status; > > /* Number of input buffers, and max we've ever had. */ > unsigned int num, max; > > + /* Work struct for refilling if we run low on memory. */ > + struct delayed_work refill; > + > + /* Chain pages by the private ptr. */ > + struct page *pages; > + > + /* RX: fragments + linear part + virtio header */ > + struct scatterlist sg[MAX_SKB_FRAGS + 2]; > +}; > + > +struct virtnet_info { > + u16 num_queue_pairs; /* # of RX/TX vq pairs */ > + > + struct send_queue *sq[MAX_QUEUES] ____cacheline_aligned_in_smp; > + struct receive_queue *rq[MAX_QUEUES] ____cacheline_aligned_in_smp; The assumption is a tx/rx pair is handled on the same cpu, yes? If yes maybe make it a single array to improve cache locality a bit? struct queue_pair { struct send_queue sq; struct receive_queue rq; }; > + struct virtqueue *cvq; > + > + struct virtio_device *vdev; > + struct net_device *dev; > + unsigned int status; > + > /* 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; > + won't checking (cvq != NULL) be enough? > /* enable config space updates */ > bool config_enable; > > /* Active statistics */ > struct virtnet_stats __percpu *stats; > > - /* Work struct for refilling if we run low on memory. */ > - struct delayed_work refill; > - > /* Work struct for config space updates */ > struct work_struct config_work; > > /* Lock for config space updates */ > struct mutex config_lock; > - > - /* Chain pages by the private ptr. */ > - struct page *pages; > - > - /* fragments + linear part + virtio header */ > - struct scatterlist rx_sg[MAX_SKB_FRAGS + 2]; > - struct scatterlist tx_sg[MAX_SKB_FRAGS + 2]; > }; > > struct skb_vnet_hdr { > @@ -108,6 +137,22 @@ struct padded_vnet_hdr { > char padding[6]; > }; > > +static inline int txq_get_qnum(struct virtnet_info *vi, struct virtqueue *vq) > +{ > + int ret = virtqueue_get_queue_index(vq); > + > + /* skip ctrl vq */ > + if (vi->has_cvq) > + return (ret - 1) / 2; > + else > + return ret / 2; > +} > + > +static inline int rxq_get_qnum(struct virtnet_info *vi, struct virtqueue *vq) > +{ > + return virtqueue_get_queue_index(vq) / 2; > +} > + > static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb) > { > return (struct skb_vnet_hdr *)skb->cb; > @@ -117,22 +162,22 @@ static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb) > * private is used to chain pages for big packets, put the whole > * most recent used list in the beginning for reuse > */ > -static void give_pages(struct virtnet_info *vi, struct page *page) > +static void give_pages(struct receive_queue *rq, struct page *page) > { > struct page *end; > > /* Find end of list, sew whole thing into vi->pages. */ > for (end = page; end->private; end = (struct page *)end->private); > - end->private = (unsigned long)vi->pages; > - vi->pages = page; > + end->private = (unsigned long)rq->pages; > + rq->pages = page; > } > > -static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask) > +static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask) > { > - struct page *p = vi->pages; > + struct page *p = rq->pages; > > if (p) { > - vi->pages = (struct page *)p->private; > + rq->pages = (struct page *)p->private; > /* clear private here, it is used to chain pages */ > p->private = 0; > } else > @@ -140,15 +185,15 @@ static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask) > return p; > } > > -static void skb_xmit_done(struct virtqueue *svq) > +static void skb_xmit_done(struct virtqueue *vq) > { > - struct virtnet_info *vi = svq->vdev->priv; > + struct virtnet_info *vi = vq->vdev->priv; > > /* Suppress further interrupts. */ > - virtqueue_disable_cb(svq); > + virtqueue_disable_cb(vq); > > /* We were probably waiting for more output buffers. */ > - netif_wake_queue(vi->dev); > + netif_wake_subqueue(vi->dev, txq_get_qnum(vi, vq)); > } > > static void set_skb_frag(struct sk_buff *skb, struct page *page, > @@ -167,9 +212,10 @@ static void set_skb_frag(struct sk_buff *skb, struct page *page, > } > > /* Called from bottom half context */ > -static struct sk_buff *page_to_skb(struct virtnet_info *vi, > +static struct sk_buff *page_to_skb(struct receive_queue *rq, > struct page *page, unsigned int len) > { > + struct virtnet_info *vi = rq->vi; > struct sk_buff *skb; > struct skb_vnet_hdr *hdr; > unsigned int copy, hdr_len, offset; > @@ -225,12 +271,12 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > } > > if (page) > - give_pages(vi, page); > + give_pages(rq, page); > > return skb; > } > > -static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb) > +static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb) > { > struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb); > struct page *page; > @@ -244,7 +290,7 @@ static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb) > skb->dev->stats.rx_length_errors++; > return -EINVAL; > } > - page = virtqueue_get_buf(vi->rvq, &len); > + page = virtqueue_get_buf(rq->vq, &len); > if (!page) { > pr_debug("%s: rx error: %d buffers missing\n", > skb->dev->name, hdr->mhdr.num_buffers); > @@ -257,13 +303,14 @@ static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb) > > set_skb_frag(skb, page, 0, &len); > > - --vi->num; > + --rq->num; > } > return 0; > } > > -static void receive_buf(struct net_device *dev, void *buf, unsigned int len) > +static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len) > { > + struct net_device *dev = rq->vi->dev; > struct virtnet_info *vi = netdev_priv(dev); > struct virtnet_stats *stats = this_cpu_ptr(vi->stats); > struct sk_buff *skb; > @@ -274,7 +321,7 @@ static void receive_buf(struct net_device *dev, void *buf, unsigned int len) > pr_debug("%s: short packet %i\n", dev->name, len); > dev->stats.rx_length_errors++; > if (vi->mergeable_rx_bufs || vi->big_packets) > - give_pages(vi, buf); > + give_pages(rq, buf); > else > dev_kfree_skb(buf); > return; > @@ -286,14 +333,14 @@ static void receive_buf(struct net_device *dev, void *buf, unsigned int len) > skb_trim(skb, len); > } else { > page = buf; > - skb = page_to_skb(vi, page, len); > + skb = page_to_skb(rq, page, len); > if (unlikely(!skb)) { > dev->stats.rx_dropped++; > - give_pages(vi, page); > + give_pages(rq, page); > return; > } > if (vi->mergeable_rx_bufs) > - if (receive_mergeable(vi, skb)) { > + if (receive_mergeable(rq, skb)) { > dev_kfree_skb(skb); > return; > } > @@ -363,90 +410,91 @@ frame_err: > dev_kfree_skb(skb); > } > > -static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp) > +static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp) > { > struct sk_buff *skb; > struct skb_vnet_hdr *hdr; > int err; > > - skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp); > + skb = __netdev_alloc_skb_ip_align(rq->vi->dev, MAX_PACKET_LEN, gfp); > if (unlikely(!skb)) > return -ENOMEM; > > skb_put(skb, MAX_PACKET_LEN); > > hdr = skb_vnet_hdr(skb); > - sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr); > + sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr); > + > + skb_to_sgvec(skb, rq->sg + 1, 0, skb->len); > > - skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len); > + err = virtqueue_add_buf(rq->vq, rq->sg, 0, 2, skb, gfp); > > - err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 2, skb, gfp); > if (err < 0) > dev_kfree_skb(skb); > > return err; > } > > -static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp) > +static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp) > { > struct page *first, *list = NULL; > char *p; > int i, err, offset; > > - /* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */ > + /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */ > for (i = MAX_SKB_FRAGS + 1; i > 1; --i) { > - first = get_a_page(vi, gfp); > + first = get_a_page(rq, gfp); > if (!first) { > if (list) > - give_pages(vi, list); > + give_pages(rq, list); > return -ENOMEM; > } > - sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE); > + sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE); > > /* chain new page in list head to match sg */ > first->private = (unsigned long)list; > list = first; > } > > - first = get_a_page(vi, gfp); > + first = get_a_page(rq, gfp); > if (!first) { > - give_pages(vi, list); > + give_pages(rq, list); > return -ENOMEM; > } > p = page_address(first); > > - /* vi->rx_sg[0], vi->rx_sg[1] share the same page */ > - /* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */ > - sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr)); > + /* rq->sg[0], rq->sg[1] share the same page */ > + /* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */ > + sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr)); > > - /* vi->rx_sg[1] for data packet, from offset */ > + /* rq->sg[1] for data packet, from offset */ > offset = sizeof(struct padded_vnet_hdr); > - sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset); > + sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset); > > /* chain first in list head */ > first->private = (unsigned long)list; > - err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2, > + err = virtqueue_add_buf(rq->vq, rq->sg, 0, MAX_SKB_FRAGS + 2, > first, gfp); > if (err < 0) > - give_pages(vi, first); > + give_pages(rq, first); > > return err; > } > > -static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp) > +static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp) > { > struct page *page; > int err; > > - page = get_a_page(vi, gfp); > + page = get_a_page(rq, gfp); > if (!page) > return -ENOMEM; > > - sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE); > + sg_init_one(rq->sg, page_address(page), PAGE_SIZE); > > - err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 1, page, gfp); > + err = virtqueue_add_buf(rq->vq, rq->sg, 0, 1, page, gfp); > if (err < 0) > - give_pages(vi, page); > + give_pages(rq, page); > > return err; > } > @@ -458,97 +506,104 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp) > * before we're receiving packets, or from refill_work which is > * careful to disable receiving (using napi_disable). > */ > -static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp) > +static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp) > { > + struct virtnet_info *vi = rq->vi; > int err; > bool oom; > > do { > if (vi->mergeable_rx_bufs) > - err = add_recvbuf_mergeable(vi, gfp); > + err = add_recvbuf_mergeable(rq, gfp); > else if (vi->big_packets) > - err = add_recvbuf_big(vi, gfp); > + err = add_recvbuf_big(rq, gfp); > else > - err = add_recvbuf_small(vi, gfp); > + err = add_recvbuf_small(rq, gfp); > > oom = err == -ENOMEM; > if (err < 0) > break; > - ++vi->num; > + ++rq->num; > } while (err > 0); > - if (unlikely(vi->num > vi->max)) > - vi->max = vi->num; > - virtqueue_kick(vi->rvq); > + if (unlikely(rq->num > rq->max)) > + rq->max = rq->num; > + virtqueue_kick(rq->vq); > return !oom; > } > > -static void skb_recv_done(struct virtqueue *rvq) > +static void skb_recv_done(struct virtqueue *vq) > { > - struct virtnet_info *vi = rvq->vdev->priv; > + struct virtnet_info *vi = vq->vdev->priv; > + struct napi_struct *napi = &vi->rq[rxq_get_qnum(vi, vq)]->napi; > + > /* Schedule NAPI, Suppress further interrupts if successful. */ > - if (napi_schedule_prep(&vi->napi)) { > - virtqueue_disable_cb(rvq); > - __napi_schedule(&vi->napi); > + if (napi_schedule_prep(napi)) { > + virtqueue_disable_cb(vq); > + __napi_schedule(napi); > } > } > > -static void virtnet_napi_enable(struct virtnet_info *vi) > +static void virtnet_napi_enable(struct receive_queue *rq) > { > - napi_enable(&vi->napi); > + napi_enable(&rq->napi); > > /* If all buffers were filled by other side before we napi_enabled, we > * won't get another interrupt, so process any outstanding packets > * now. virtnet_poll wants re-enable the queue, so we disable here. > * We synchronize against interrupts via NAPI_STATE_SCHED */ > - if (napi_schedule_prep(&vi->napi)) { > - virtqueue_disable_cb(vi->rvq); > + if (napi_schedule_prep(&rq->napi)) { > + virtqueue_disable_cb(rq->vq); > local_bh_disable(); > - __napi_schedule(&vi->napi); > + __napi_schedule(&rq->napi); > local_bh_enable(); > } > } > > static void refill_work(struct work_struct *work) > { > - struct virtnet_info *vi; > + struct napi_struct *napi; > + struct receive_queue *rq; > bool still_empty; > > - vi = container_of(work, struct virtnet_info, refill.work); > - napi_disable(&vi->napi); > - still_empty = !try_fill_recv(vi, GFP_KERNEL); > - virtnet_napi_enable(vi); > + rq = container_of(work, struct receive_queue, refill.work); > + napi = &rq->napi; > + > + napi_disable(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) > - queue_delayed_work(system_nrt_wq, &vi->refill, HZ/2); > + queue_delayed_work(system_nrt_wq, &rq->refill, HZ/2); > } > > static int virtnet_poll(struct napi_struct *napi, int budget) > { > - struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi); > + struct receive_queue *rq = container_of(napi, struct receive_queue, > + napi); > void *buf; > unsigned int len, received = 0; > > again: > while (received < budget && > - (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) { > - receive_buf(vi->dev, buf, len); > - --vi->num; > + (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) { > + receive_buf(rq, buf, len); > + --rq->num; > received++; > } > > - if (vi->num < vi->max / 2) { > - if (!try_fill_recv(vi, GFP_ATOMIC)) > - queue_delayed_work(system_nrt_wq, &vi->refill, 0); > + if (rq->num < rq->max / 2) { > + if (!try_fill_recv(rq, GFP_ATOMIC)) > + queue_delayed_work(system_nrt_wq, &rq->refill, 0); > } > > /* Out of packets? */ > if (received < budget) { > napi_complete(napi); > - if (unlikely(!virtqueue_enable_cb(vi->rvq)) && > + if (unlikely(!virtqueue_enable_cb(rq->vq)) && > napi_schedule_prep(napi)) { > - virtqueue_disable_cb(vi->rvq); > + virtqueue_disable_cb(rq->vq); > __napi_schedule(napi); > goto again; > } > @@ -557,13 +612,14 @@ again: > return received; > } > > -static unsigned int free_old_xmit_skbs(struct virtnet_info *vi) > +static unsigned int free_old_xmit_skbs(struct virtnet_info *vi, > + struct virtqueue *vq) > { > struct sk_buff *skb; > unsigned int len, tot_sgs = 0; > struct virtnet_stats *stats = this_cpu_ptr(vi->stats); > > - while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) { > + while ((skb = virtqueue_get_buf(vq, &len)) != NULL) { > pr_debug("Sent skb %p\n", skb); > > u64_stats_update_begin(&stats->tx_syncp); > @@ -577,7 +633,8 @@ static unsigned int free_old_xmit_skbs(struct virtnet_info *vi) > return tot_sgs; > } > > -static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb) > +static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb, > + struct virtqueue *vq, struct scatterlist *sg) > { > struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb); > const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; > @@ -615,44 +672,47 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb) > > /* Encode metadata header at front. */ > if (vi->mergeable_rx_bufs) > - sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr); > + sg_set_buf(sg, &hdr->mhdr, sizeof hdr->mhdr); > else > - sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr); > + sg_set_buf(sg, &hdr->hdr, sizeof hdr->hdr); > > - hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1; > - return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg, > + hdr->num_sg = skb_to_sgvec(skb, sg + 1, 0, skb->len) + 1; > + return virtqueue_add_buf(vq, sg, hdr->num_sg, > 0, skb, GFP_ATOMIC); > } > > static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > { > struct virtnet_info *vi = netdev_priv(dev); > + int qnum = skb_get_queue_mapping(skb); > + struct virtqueue *vq = vi->sq[qnum]->vq; > int capacity; > > /* Free up any pending old buffers before queueing new ones. */ > - free_old_xmit_skbs(vi); > + free_old_xmit_skbs(vi, vq); > > /* Try to transmit */ > - capacity = xmit_skb(vi, skb); > + capacity = xmit_skb(vi, skb, vq, vi->sq[qnum]->sg); > > /* This can happen with OOM and indirect buffers. */ > if (unlikely(capacity < 0)) { > 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); > return NETDEV_TX_OK; > } > - virtqueue_kick(vi->svq); > + virtqueue_kick(vq); > > /* Don't wait up for transmitted skbs to be freed. */ > skb_orphan(skb); > @@ -661,13 +721,13 @@ 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); > - if (unlikely(!virtqueue_enable_cb_delayed(vi->svq))) { > + netif_stop_subqueue(dev, qnum); > + if (unlikely(!virtqueue_enable_cb_delayed(vq))) { > /* More just got used, free them then recheck. */ > - capacity += free_old_xmit_skbs(vi); > + capacity += free_old_xmit_skbs(vi, vq); > if (capacity >= 2+MAX_SKB_FRAGS) { > - netif_start_queue(dev); > - virtqueue_disable_cb(vi->svq); > + netif_start_subqueue(dev, qnum); > + virtqueue_disable_cb(vq); > } > } > } > @@ -700,7 +760,8 @@ static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev, > unsigned int start; > > for_each_possible_cpu(cpu) { > - struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu); > + struct virtnet_stats __percpu *stats > + = per_cpu_ptr(vi->stats, cpu); > u64 tpackets, tbytes, rpackets, rbytes; > > do { > @@ -734,20 +795,26 @@ 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->napi); > + for (i = 0; i < vi->num_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); > + int i; > > - /* Make sure we have some buffers: if oom use wq. */ > - if (!try_fill_recv(vi, GFP_KERNEL)) > - queue_delayed_work(system_nrt_wq, &vi->refill, 0); > + for (i = 0; i < vi->num_queue_pairs; i++) { > + /* Make sure we have some buffers: if oom use wq. */ > + if (!try_fill_recv(vi->rq[i], GFP_KERNEL)) > + queue_delayed_work(system_nrt_wq, > + &vi->rq[i]->refill, 0); > + virtnet_napi_enable(vi->rq[i]); > + } > > - virtnet_napi_enable(vi); > return 0; > } > > @@ -809,10 +876,13 @@ static void virtnet_ack_link_announce(struct virtnet_info *vi) > 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->napi); > + for (i = 0; i < vi->num_queue_pairs; i++) { > + cancel_delayed_work_sync(&vi->rq[i]->refill); > + napi_disable(&vi->rq[i]->napi); > + } > > return 0; > } > @@ -924,11 +994,10 @@ 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->rvq); > - ring->tx_max_pending = virtqueue_get_vring_size(vi->svq); > + 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; > - > } > > > @@ -961,6 +1030,19 @@ 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. > + */ > +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, > @@ -972,6 +1054,7 @@ 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 > @@ -1007,10 +1090,10 @@ 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); > @@ -1023,41 +1106,217 @@ static void virtnet_config_changed(struct virtio_device *vdev) > queue_work(system_nrt_wq, &vi->config_work); > } > > -static int init_vqs(struct virtnet_info *vi) > +static void free_receive_bufs(struct virtnet_info *vi) > +{ > + int i; > + > + for (i = 0; i < vi->num_queue_pairs; i++) { > + while (vi->rq[i]->pages) > + __free_pages(get_a_page(vi->rq[i], GFP_KERNEL), 0); > + } > +} > + > +/* Free memory allocated for send and receive queues */ > +static void virtnet_free_queues(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->num_queue_pairs; i++) { > + kfree(vi->rq[i]); > + vi->rq[i] = NULL; > + kfree(vi->sq[i]); > + vi->sq[i] = NULL; > + } > +} > > - err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names); > - if (err) > - return err; > +static void free_unused_bufs(struct virtnet_info *vi) > +{ > + void *buf; > + int i; > + > + for (i = 0; i < vi->num_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->num_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; > + > + if (vi->num_queue_pairs == 1) > + return; > + > + for (i = 0; i < vi->num_queue_pairs; i++) { > + int cpu = set ? i : -1; > + virtqueue_set_affinity(vi->rq[i]->vq, cpu); > + virtqueue_set_affinity(vi->sq[i]->vq, cpu); > + } > + return; > +} > + > +static void virtnet_del_vqs(struct virtnet_info *vi) > +{ > + struct virtio_device *vdev = vi->vdev; > + > + virtnet_set_affinity(vi, false); > + > + vdev->config->del_vqs(vdev); > + > + virtnet_free_queues(vi); > +} > + > +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; > > - vi->rvq = vqs[0]; > - vi->svq = vqs[1]; > + /* > + * We expect 1 RX virtqueue followed by 1 TX virtqueue, followd by > + * possible control virtqueue and followed by the same > + * 'vi->num_queue_pairs-1' more times > + */ > + total_vqs = vi->num_queue_pairs * 2 + > + virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ); > + > + /* Allocate space for find_vqs parameters */ > + vqs = kmalloc(total_vqs * sizeof(*vqs), GFP_KERNEL); > + callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL); > + names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL); so this needs to be kzalloc otherwise on an error cleanup will get uninitialized data and crash? > + if (!vqs || !callbacks || !names) > + goto err; > + > + /* Parameters for control virtqueue, if any */ > + if (vi->has_cvq) { > + callbacks[2] = NULL; > + names[2] = "control"; > + } > + > + /* Allocate/initialize parameters for send/receive virtqueues */ > + for (i = 0; i < vi->num_queue_pairs * 2; i += 2) { > + int j = (i == 0 ? i : i + vi->has_cvq); > + callbacks[j] = skb_recv_done; > + callbacks[j + 1] = skb_xmit_done; > + names[j] = kasprintf(GFP_KERNEL, "input.%d", i / 2); > + names[j + 1] = kasprintf(GFP_KERNEL, "output.%d", i / 2); This needs wrappers. E.g. virtnet_rx_vq(int queue_pair), virtnet_tx_vq(int queue_pair); Then you would just scan 0 to num_queue_pairs, and i is queue pair number. > + } > > - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) { > + ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks, > + (const char **)names); > + if (ret) > + goto err; > + > + if (vi->has_cvq) > vi->cvq = vqs[2]; > > - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN)) > - vi->dev->features |= NETIF_F_HW_VLAN_FILTER; > + for (i = 0; i < vi->num_queue_pairs * 2; i += 2) { > + int j = i == 0 ? i : i + vi->has_cvq; > + vi->rq[i / 2]->vq = vqs[j]; > + vi->sq[i / 2]->vq = vqs[j + 1]; Same here. > } > - return 0; > + > +err: > + if (ret && names) If we are here ret != 0. For names, just add another label, don't complicate cleanup. > + for (i = 0; i < vi->num_queue_pairs * 2; i++) > + kfree(names[i]); > + > + kfree(names); > + kfree(callbacks); > + kfree(vqs); > + > + return ret; > +} > + > +static int virtnet_alloc_queues(struct virtnet_info *vi) > +{ > + int ret = -ENOMEM; > + int i; > + > + for (i = 0; i < vi->num_queue_pairs; i++) { > + vi->rq[i] = kzalloc(sizeof(*vi->rq[i]), GFP_KERNEL); > + vi->sq[i] = kzalloc(sizeof(*vi->sq[i]), GFP_KERNEL); > + if (!vi->rq[i] || !vi->sq[i]) > + goto err; > + } > + > + ret = 0; > + > + /* setup initial receive and send queue parameters */ > + for (i = 0; i < vi->num_queue_pairs; i++) { > + vi->rq[i]->vi = vi; > + vi->rq[i]->pages = NULL; > + INIT_DELAYED_WORK(&vi->rq[i]->refill, refill_work); > + 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)); > + } > + Add return 0 here, then ret = 0 will not be needed above and if (ret) below. > +err: > + if (ret) > + virtnet_free_queues(vi); > + > + return ret; > +} > + > +static int virtnet_setup_vqs(struct virtnet_info *vi) > +{ > + int ret; > + > + /* Allocate send & receive queues */ > + ret = virtnet_alloc_queues(vi); > + if (!ret) { > + ret = virtnet_find_vqs(vi); > + if (ret) > + virtnet_free_queues(vi); > + else > + virtnet_set_affinity(vi, true); > + } > + > + return ret; Add some labels for error handling, this if nesting is messy. > } > > static int virtnet_probe(struct virtio_device *vdev) > { > - int err; > + int i, err; > struct net_device *dev; > struct virtnet_info *vi; > + u16 num_queues, num_queue_pairs; > + > + /* Find if host supports multiqueue virtio_net device */ > + err = virtio_config_val(vdev, VIRTIO_NET_F_MULTIQUEUE, > + offsetof(struct virtio_net_config, > + num_queues), &num_queues); > + > + /* We need atleast 2 queue's */ typo > + if (err || num_queues < 2) > + num_queues = 2; > + if (num_queues > MAX_QUEUES * 2) > + num_queues = MAX_QUEUES; > + > + num_queue_pairs = num_queues / 2; > > /* 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), num_queue_pairs); > if (!dev) > return -ENOMEM; > > @@ -1103,22 +1362,18 @@ static int virtnet_probe(struct virtio_device *vdev) > > /* Set up our device-specific information */ > vi = netdev_priv(dev); > - netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight); > vi->dev = dev; > vi->vdev = vdev; > vdev->priv = vi; > - vi->pages = NULL; > vi->stats = alloc_percpu(struct virtnet_stats); > err = -ENOMEM; > if (vi->stats == NULL) > - goto free; > + goto free_netdev; > > - 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->rx_sg, ARRAY_SIZE(vi->rx_sg)); > - sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg)); > + vi->num_queue_pairs = num_queue_pairs; > > /* If we can receive ANY GSO packets, we must allocate large ones. */ > if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) || > @@ -1129,9 +1384,17 @@ static int virtnet_probe(struct virtio_device *vdev) > if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) > vi->mergeable_rx_bufs = true; > > - err = init_vqs(vi); > + if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > + vi->has_cvq = true; > + How about we disable multiqueue if there's no cvq? Will make logic a bit simpler, won't it? > + /* Allocate/initialize the rx/tx queues, and invoke find_vqs */ > + err = virtnet_setup_vqs(vi); > if (err) > - goto free_stats; > + goto free_netdev; > + > + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) && > + virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN)) > + dev->features |= NETIF_F_HW_VLAN_FILTER; > > err = register_netdev(dev); > if (err) { > @@ -1140,12 +1403,15 @@ static int virtnet_probe(struct virtio_device *vdev) > } > > /* Last of all, set up some receive buffers. */ > - try_fill_recv(vi, GFP_KERNEL); > - > - /* If we didn't even get one input buffer, we're useless. */ > - if (vi->num == 0) { > - err = -ENOMEM; > - goto unregister; > + for (i = 0; i < num_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, > @@ -1158,42 +1424,25 @@ 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, num_queue_pairs); > + > return 0; > > -unregister: > +free_recv_bufs: > + free_receive_bufs(vi); > unregister_netdev(dev); > + > free_vqs: > - vdev->config->del_vqs(vdev); > -free_stats: > - free_percpu(vi->stats); > -free: > + for (i = 0; i < num_queue_pairs; i++) > + cancel_delayed_work_sync(&vi->rq[i]->refill); > + virtnet_del_vqs(vi); > + > +free_netdev: > free_netdev(dev); > return err; > } > > -static void free_unused_bufs(struct virtnet_info *vi) > -{ > - void *buf; > - while (1) { > - buf = virtqueue_detach_unused_buf(vi->svq); > - if (!buf) > - break; > - dev_kfree_skb(buf); > - } > - while (1) { > - buf = virtqueue_detach_unused_buf(vi->rvq); > - if (!buf) > - break; > - if (vi->mergeable_rx_bufs || vi->big_packets) > - give_pages(vi, buf); > - else > - dev_kfree_skb(buf); > - --vi->num; > - } > - BUG_ON(vi->num != 0); > -} > - > static void remove_vq_common(struct virtnet_info *vi) > { > vi->vdev->config->reset(vi->vdev); > @@ -1201,10 +1450,9 @@ 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->pages) > - __free_pages(get_a_page(vi, GFP_KERNEL), 0); > + virtnet_del_vqs(vi); > } > > static void __devexit virtnet_remove(struct virtio_device *vdev) > @@ -1230,6 +1478,7 @@ 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); > @@ -1237,10 +1486,13 @@ static int virtnet_freeze(struct virtio_device *vdev) > mutex_unlock(&vi->config_lock); > > netif_device_detach(vi->dev); > - cancel_delayed_work_sync(&vi->refill); > + for (i = 0; i < vi->num_queue_pairs; i++) > + cancel_delayed_work_sync(&vi->rq[i]->refill); > > if (netif_running(vi->dev)) > - napi_disable(&vi->napi); > + for (i = 0; i < vi->num_queue_pairs; i++) > + napi_disable(&vi->rq[i]->napi); > + > > remove_vq_common(vi); > > @@ -1252,19 +1504,22 @@ 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); > + err = virtnet_setup_vqs(vi); > if (err) > return err; > > if (netif_running(vi->dev)) > - virtnet_napi_enable(vi); > + for (i = 0; i < vi->num_queue_pairs; i++) > + virtnet_napi_enable(vi->rq[i]); > > netif_device_attach(vi->dev); > > - if (!try_fill_recv(vi, GFP_KERNEL)) > - queue_delayed_work(system_nrt_wq, &vi->refill, 0); > + for (i = 0; i < vi->num_queue_pairs; i++) > + if (!try_fill_recv(vi->rq[i], GFP_KERNEL)) > + queue_delayed_work(system_nrt_wq, > + &vi->rq[i]->refill, 0); > > mutex_lock(&vi->config_lock); > vi->config_enable = true; > @@ -1287,7 +1542,7 @@ 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_MULTIQUEUE, > }; > > static struct virtio_driver virtio_net_driver = { > diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h > index 1bc7e30..60f09ff 100644 > --- a/include/linux/virtio_net.h > +++ b/include/linux/virtio_net.h > @@ -61,6 +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 */ > + __u16 num_queues; > } __attribute__((packed)); > > /* This is the first element of the scatter-gather list. If you don't > -- > 1.7.1