Messages in this thread | | | Date | Mon, 23 Jul 2012 13:48:35 +0800 | From | Jason Wang <> | Subject | Re: [net-next RFC V5 4/5] virtio_net: multiqueue support |
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On 07/20/2012 09:40 PM, Michael S. Tsirkin wrote: > 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<krkumar2@in.ibm.com> >> Signed-off-by: Jason Wang<jasowang@redhat.com> > 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.
Sure, thanks for the reviewing. > > 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<linux/scatterlist.h> >> #include<linux/if_vlan.h> >> #include<linux/slab.h> >> +#include<linux/interrupt.h> >> >> 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?
Sure. >> @@ -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; > };
Ok. >> + 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?
Enough, so has_cvq is dupliated with vi->cvq. I will remove it in next version. > >> /* 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?
Yes, will change it to use kzalloc. > >> + 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.
Ok. >> + } >> >> - 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.
Consider the code is really simple, seem no need to use helpers. > >> } >> - return 0; >> + >> +err: >> + if (ret&& names) > If we are here ret != 0. For names, just add another label, don't > complicate cleanup.
Ok. >> + 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. >
Ok. >> +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.
Ok. >> } >> >> 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
Will fix this, thanks. >> + 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?
We can, but as you said, just let the logic simpler a bit. >> + /* 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
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