diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index cca871346a0ff5cfe22ffbcdce0f8c973cf59214..88a70f5ed594a0214703abeb6aa0cbab6250ae13 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -77,7 +77,9 @@ struct netfront_cb { #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE) #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE) -#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256) + +/* Minimum number of Rx slots (includes slot for GSO metadata). */ +#define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1) /* Queue name is interface name with "-qNNN" appended */ #define QUEUE_NAME_SIZE (IFNAMSIZ + 6) @@ -137,13 +139,6 @@ struct netfront_queue { struct xen_netif_rx_front_ring rx; int rx_ring_ref; - /* Receive-ring batched refills. */ -#define RX_MIN_TARGET 8 -#define RX_DFL_MIN_TARGET 64 -#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) - unsigned rx_min_target, rx_max_target, rx_target; - struct sk_buff_head rx_batch; - struct timer_list rx_refill_timer; struct sk_buff *rx_skbs[NET_RX_RING_SIZE]; @@ -251,7 +246,7 @@ static void rx_refill_timeout(unsigned long data) static int netfront_tx_slot_available(struct netfront_queue *queue) { return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) < - (TX_MAX_TARGET - MAX_SKB_FRAGS - 2); + (NET_TX_RING_SIZE - MAX_SKB_FRAGS - 2); } static void xennet_maybe_wake_tx(struct netfront_queue *queue) @@ -265,77 +260,55 @@ static void xennet_maybe_wake_tx(struct netfront_queue *queue) netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id)); } -static void xennet_alloc_rx_buffers(struct netfront_queue *queue) + +static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue) { - unsigned short id; struct sk_buff *skb; struct page *page; - int i, batch_target, notify; - RING_IDX req_prod = queue->rx.req_prod_pvt; - grant_ref_t ref; - unsigned long pfn; - void *vaddr; - struct xen_netif_rx_request *req; - if (unlikely(!netif_carrier_ok(queue->info->netdev))) - return; + skb = __netdev_alloc_skb(queue->info->netdev, + RX_COPY_THRESHOLD + NET_IP_ALIGN, + GFP_ATOMIC | __GFP_NOWARN); + if (unlikely(!skb)) + return NULL; - /* - * Allocate skbuffs greedily, even though we batch updates to the - * receive ring. This creates a less bursty demand on the memory - * allocator, so should reduce the chance of failed allocation requests - * both for ourself and for other kernel subsystems. - */ - batch_target = queue->rx_target - (req_prod - queue->rx.rsp_cons); - for (i = skb_queue_len(&queue->rx_batch); i < batch_target; i++) { - skb = __netdev_alloc_skb(queue->info->netdev, - RX_COPY_THRESHOLD + NET_IP_ALIGN, - GFP_ATOMIC | __GFP_NOWARN); - if (unlikely(!skb)) - goto no_skb; - - /* Align ip header to a 16 bytes boundary */ - skb_reserve(skb, NET_IP_ALIGN); - - page = alloc_page(GFP_ATOMIC | __GFP_NOWARN); - if (!page) { - kfree_skb(skb); -no_skb: - /* Could not allocate any skbuffs. Try again later. */ - mod_timer(&queue->rx_refill_timer, - jiffies + (HZ/10)); - - /* Any skbuffs queued for refill? Force them out. */ - if (i != 0) - goto refill; - break; - } - - skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE); - __skb_queue_tail(&queue->rx_batch, skb); + page = alloc_page(GFP_ATOMIC | __GFP_NOWARN); + if (!page) { + kfree_skb(skb); + return NULL; } + skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE); + + /* Align ip header to a 16 bytes boundary */ + skb_reserve(skb, NET_IP_ALIGN); + skb->dev = queue->info->netdev; + + return skb; +} + - /* Is the batch large enough to be worthwhile? */ - if (i < (queue->rx_target/2)) { - if (req_prod > queue->rx.sring->req_prod) - goto push; +static void xennet_alloc_rx_buffers(struct netfront_queue *queue) +{ + RING_IDX req_prod = queue->rx.req_prod_pvt; + int notify; + + if (unlikely(!netif_carrier_ok(queue->info->netdev))) return; - } - /* Adjust our fill target if we risked running out of buffers. */ - if (((req_prod - queue->rx.sring->rsp_prod) < (queue->rx_target / 4)) && - ((queue->rx_target *= 2) > queue->rx_max_target)) - queue->rx_target = queue->rx_max_target; + for (req_prod = queue->rx.req_prod_pvt; + req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE; + req_prod++) { + struct sk_buff *skb; + unsigned short id; + grant_ref_t ref; + unsigned long pfn; + struct xen_netif_rx_request *req; - refill: - for (i = 0; ; i++) { - skb = __skb_dequeue(&queue->rx_batch); - if (skb == NULL) + skb = xennet_alloc_one_rx_buffer(queue); + if (!skb) break; - skb->dev = queue->info->netdev; - - id = xennet_rxidx(req_prod + i); + id = xennet_rxidx(req_prod); BUG_ON(queue->rx_skbs[id]); queue->rx_skbs[id] = skb; @@ -345,9 +318,8 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue) queue->grant_rx_ref[id] = ref; pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0])); - vaddr = page_address(skb_frag_page(&skb_shinfo(skb)->frags[0])); - req = RING_GET_REQUEST(&queue->rx, req_prod + i); + req = RING_GET_REQUEST(&queue->rx, req_prod); gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id, pfn_to_mfn(pfn), @@ -357,11 +329,16 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue) req->gref = ref; } + queue->rx.req_prod_pvt = req_prod; + + /* Not enough requests? Try again later. */ + if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN) { + mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10)); + return; + } + wmb(); /* barrier so backend seens requests */ - /* Above is a suitable barrier to ensure backend will see requests. */ - queue->rx.req_prod_pvt = req_prod + i; - push: RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify); if (notify) notify_remote_via_irq(queue->rx_irq); @@ -1070,13 +1047,6 @@ static int xennet_poll(struct napi_struct *napi, int budget) work_done -= handle_incoming_queue(queue, &rxq); - /* If we get a callback with very few responses, reduce fill target. */ - /* NB. Note exponential increase, linear decrease. */ - if (((queue->rx.req_prod_pvt - queue->rx.sring->rsp_prod) > - ((3*queue->rx_target) / 4)) && - (--queue->rx_target < queue->rx_min_target)) - queue->rx_target = queue->rx_min_target; - xennet_alloc_rx_buffers(queue); if (work_done < budget) { @@ -1643,11 +1613,6 @@ static int xennet_init_queue(struct netfront_queue *queue) spin_lock_init(&queue->tx_lock); spin_lock_init(&queue->rx_lock); - skb_queue_head_init(&queue->rx_batch); - queue->rx_target = RX_DFL_MIN_TARGET; - queue->rx_min_target = RX_DFL_MIN_TARGET; - queue->rx_max_target = RX_MAX_TARGET; - init_timer(&queue->rx_refill_timer); queue->rx_refill_timer.data = (unsigned long)queue; queue->rx_refill_timer.function = rx_refill_timeout; @@ -1670,7 +1635,7 @@ static int xennet_init_queue(struct netfront_queue *queue) } /* A grant for every tx ring slot */ - if (gnttab_alloc_grant_references(TX_MAX_TARGET, + if (gnttab_alloc_grant_references(NET_TX_RING_SIZE, &queue->gref_tx_head) < 0) { pr_alert("can't alloc tx grant refs\n"); err = -ENOMEM; @@ -1678,7 +1643,7 @@ static int xennet_init_queue(struct netfront_queue *queue) } /* A grant for every rx ring slot */ - if (gnttab_alloc_grant_references(RX_MAX_TARGET, + if (gnttab_alloc_grant_references(NET_RX_RING_SIZE, &queue->gref_rx_head) < 0) { pr_alert("can't alloc rx grant refs\n"); err = -ENOMEM; @@ -2146,83 +2111,18 @@ static const struct ethtool_ops xennet_ethtool_ops = }; #ifdef CONFIG_SYSFS -static ssize_t show_rxbuf_min(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct net_device *netdev = to_net_dev(dev); - struct netfront_info *info = netdev_priv(netdev); - unsigned int num_queues = netdev->real_num_tx_queues; - - if (num_queues) - return sprintf(buf, "%u\n", info->queues[0].rx_min_target); - else - return sprintf(buf, "%u\n", RX_MIN_TARGET); -} - -static ssize_t store_rxbuf_min(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t len) +static ssize_t show_rxbuf(struct device *dev, + struct device_attribute *attr, char *buf) { - struct net_device *netdev = to_net_dev(dev); - struct netfront_info *np = netdev_priv(netdev); - unsigned int num_queues = netdev->real_num_tx_queues; - char *endp; - unsigned long target; - unsigned int i; - struct netfront_queue *queue; - - if (!capable(CAP_NET_ADMIN)) - return -EPERM; - - target = simple_strtoul(buf, &endp, 0); - if (endp == buf) - return -EBADMSG; - - if (target < RX_MIN_TARGET) - target = RX_MIN_TARGET; - if (target > RX_MAX_TARGET) - target = RX_MAX_TARGET; - - for (i = 0; i < num_queues; ++i) { - queue = &np->queues[i]; - spin_lock_bh(&queue->rx_lock); - if (target > queue->rx_max_target) - queue->rx_max_target = target; - queue->rx_min_target = target; - if (target > queue->rx_target) - queue->rx_target = target; - - xennet_alloc_rx_buffers(queue); - - spin_unlock_bh(&queue->rx_lock); - } - return len; -} - -static ssize_t show_rxbuf_max(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct net_device *netdev = to_net_dev(dev); - struct netfront_info *info = netdev_priv(netdev); - unsigned int num_queues = netdev->real_num_tx_queues; - - if (num_queues) - return sprintf(buf, "%u\n", info->queues[0].rx_max_target); - else - return sprintf(buf, "%u\n", RX_MAX_TARGET); + return sprintf(buf, "%lu\n", NET_RX_RING_SIZE); } -static ssize_t store_rxbuf_max(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t len) +static ssize_t store_rxbuf(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) { - struct net_device *netdev = to_net_dev(dev); - struct netfront_info *np = netdev_priv(netdev); - unsigned int num_queues = netdev->real_num_tx_queues; char *endp; unsigned long target; - unsigned int i = 0; - struct netfront_queue *queue = NULL; if (!capable(CAP_NET_ADMIN)) return -EPERM; @@ -2231,44 +2131,15 @@ static ssize_t store_rxbuf_max(struct device *dev, if (endp == buf) return -EBADMSG; - if (target < RX_MIN_TARGET) - target = RX_MIN_TARGET; - if (target > RX_MAX_TARGET) - target = RX_MAX_TARGET; - - for (i = 0; i < num_queues; ++i) { - queue = &np->queues[i]; - spin_lock_bh(&queue->rx_lock); - if (target < queue->rx_min_target) - queue->rx_min_target = target; - queue->rx_max_target = target; - if (target < queue->rx_target) - queue->rx_target = target; - - xennet_alloc_rx_buffers(queue); + /* rxbuf_min and rxbuf_max are no longer configurable. */ - spin_unlock_bh(&queue->rx_lock); - } return len; } -static ssize_t show_rxbuf_cur(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct net_device *netdev = to_net_dev(dev); - struct netfront_info *info = netdev_priv(netdev); - unsigned int num_queues = netdev->real_num_tx_queues; - - if (num_queues) - return sprintf(buf, "%u\n", info->queues[0].rx_target); - else - return sprintf(buf, "0\n"); -} - static struct device_attribute xennet_attrs[] = { - __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min), - __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max), - __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL), + __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf), + __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf), + __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf, NULL), }; static int xennet_sysfs_addif(struct net_device *netdev)