[PATCH net-next v3 03/10] tun: switch to net core provided statistics counters

Switch tun to the standard statistics pattern: - use netdev->stats for the less frequently accessed counters - use netdev->tstats for the frequently accessed per-cpu counters v3: - add atomic_long_t member rx_frame_errors for making counter updates atomic Signed-off-by: Heiner Kallweit <hkallweit1(a)gmail.com> --- drivers/net/tun.c | 121 +++++++++++++--------------------------------- 1 file changed, 34 insertions(+), 87 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index be69d2720..3d45d5617 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -107,17 +107,6 @@ struct tap_filter { #define TUN_FLOW_EXPIRE (3 * HZ) -struct tun_pcpu_stats { - u64_stats_t rx_packets; - u64_stats_t rx_bytes; - u64_stats_t tx_packets; - u64_stats_t tx_bytes; - struct u64_stats_sync syncp; - u32 rx_dropped; - u32 tx_dropped; - u32 rx_frame_errors; -}; - /* A tun_file connects an open character device to a tuntap netdevice. It * also contains all socket related structures (except sock_fprog and tap_filter) * to serve as one transmit queue for tuntap device. The sock_fprog and @@ -207,7 +196,7 @@ struct tun_struct { void *security; u32 flow_count; u32 rx_batched; - struct tun_pcpu_stats __percpu *pcpu_stats; + atomic_long_t rx_frame_errors; struct bpf_prog __rcu *xdp_prog; struct tun_prog __rcu *steering_prog; struct tun_prog __rcu *filter_prog; @@ -1066,7 +1055,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) return NETDEV_TX_OK; drop: - this_cpu_inc(tun->pcpu_stats->tx_dropped); + atomic_long_inc(&dev->tx_dropped); skb_tx_error(skb); kfree_skb(skb); rcu_read_unlock(); @@ -1103,37 +1092,12 @@ static void tun_set_headroom(struct net_device *dev, int new_hr) static void tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) { - u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0; struct tun_struct *tun = netdev_priv(dev); - struct tun_pcpu_stats *p; - int i; - - for_each_possible_cpu(i) { - u64 rxpackets, rxbytes, txpackets, txbytes; - unsigned int start; - p = per_cpu_ptr(tun->pcpu_stats, i); - do { - start = u64_stats_fetch_begin(&p->syncp); - rxpackets = u64_stats_read(&p->rx_packets); - rxbytes = u64_stats_read(&p->rx_bytes); - txpackets = u64_stats_read(&p->tx_packets); - txbytes = u64_stats_read(&p->tx_bytes); - } while (u64_stats_fetch_retry(&p->syncp, start)); + dev_get_tstats64(dev, stats); - stats->rx_packets += rxpackets; - stats->rx_bytes += rxbytes; - stats->tx_packets += txpackets; - stats->tx_bytes += txbytes; - - /* u32 counters */ - rx_dropped += p->rx_dropped; - rx_frame_errors += p->rx_frame_errors; - tx_dropped += p->tx_dropped; - } - stats->rx_dropped = rx_dropped; - stats->rx_frame_errors = rx_frame_errors; - stats->tx_dropped = tx_dropped; + stats->rx_frame_errors += + (unsigned long)atomic_long_read(&tun->rx_frame_errors); } static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog, @@ -1247,7 +1211,7 @@ static int tun_xdp_xmit(struct net_device *dev, int n, void *frame = tun_xdp_to_ptr(xdp); if (__ptr_ring_produce(&tfile->tx_ring, frame)) { - this_cpu_inc(tun->pcpu_stats->tx_dropped); + atomic_long_inc(&dev->tx_dropped); xdp_return_frame_rx_napi(xdp); drops++; } @@ -1283,7 +1247,7 @@ static const struct net_device_ops tap_netdev_ops = { .ndo_select_queue = tun_select_queue, .ndo_features_check = passthru_features_check, .ndo_set_rx_headroom = tun_set_headroom, - .ndo_get_stats64 = tun_net_get_stats64, + .ndo_get_stats64 = dev_get_tstats64, .ndo_bpf = tun_xdp, .ndo_xdp_xmit = tun_xdp_xmit, .ndo_change_carrier = tun_net_change_carrier, @@ -1577,7 +1541,7 @@ static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog, trace_xdp_exception(tun->dev, xdp_prog, act); fallthrough; case XDP_DROP: - this_cpu_inc(tun->pcpu_stats->rx_dropped); + atomic_long_inc(&tun->dev->rx_dropped); break; } @@ -1683,7 +1647,6 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, size_t total_len = iov_iter_count(from); size_t len = total_len, align = tun->align, linear; struct virtio_net_hdr gso = { 0 }; - struct tun_pcpu_stats *stats; int good_linear; int copylen; bool zerocopy = false; @@ -1752,7 +1715,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, */ skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp); if (IS_ERR(skb)) { - this_cpu_inc(tun->pcpu_stats->rx_dropped); + atomic_long_inc(&tun->dev->rx_dropped); return PTR_ERR(skb); } if (!skb) @@ -1781,7 +1744,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (IS_ERR(skb)) { if (PTR_ERR(skb) != -EAGAIN) - this_cpu_inc(tun->pcpu_stats->rx_dropped); + atomic_long_inc(&tun->dev->rx_dropped); if (frags) mutex_unlock(&tfile->napi_mutex); return PTR_ERR(skb); @@ -1795,7 +1758,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (err) { err = -EFAULT; drop: - this_cpu_inc(tun->pcpu_stats->rx_dropped); + atomic_long_inc(&tun->dev->rx_dropped); kfree_skb(skb); if (frags) { tfile->napi.skb = NULL; @@ -1807,7 +1770,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) { - this_cpu_inc(tun->pcpu_stats->rx_frame_errors); + atomic_long_inc(&tun->rx_frame_errors); kfree_skb(skb); if (frags) { tfile->napi.skb = NULL; @@ -1830,7 +1793,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, pi.proto = htons(ETH_P_IPV6); break; default: - this_cpu_inc(tun->pcpu_stats->rx_dropped); + atomic_long_inc(&tun->dev->rx_dropped); kfree_skb(skb); return -EINVAL; } @@ -1910,7 +1873,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, skb_headlen(skb)); if (unlikely(headlen > skb_headlen(skb))) { - this_cpu_inc(tun->pcpu_stats->rx_dropped); + atomic_long_inc(&tun->dev->rx_dropped); napi_free_frags(&tfile->napi); rcu_read_unlock(); mutex_unlock(&tfile->napi_mutex); @@ -1942,12 +1905,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } rcu_read_unlock(); - stats = get_cpu_ptr(tun->pcpu_stats); - u64_stats_update_begin(&stats->syncp); - u64_stats_inc(&stats->rx_packets); - u64_stats_add(&stats->rx_bytes, len); - u64_stats_update_end(&stats->syncp); - put_cpu_ptr(stats); + preempt_disable(); + dev_sw_netstats_rx_add(tun->dev, len); + preempt_enable(); if (rxhash) tun_flow_update(tun, rxhash, tfile); @@ -1979,7 +1939,6 @@ static ssize_t tun_put_user_xdp(struct tun_struct *tun, { int vnet_hdr_sz = 0; size_t size = xdp_frame->len; - struct tun_pcpu_stats *stats; size_t ret; if (tun->flags & IFF_VNET_HDR) { @@ -1996,12 +1955,9 @@ static ssize_t tun_put_user_xdp(struct tun_struct *tun, ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz; - stats = get_cpu_ptr(tun->pcpu_stats); - u64_stats_update_begin(&stats->syncp); - u64_stats_inc(&stats->tx_packets); - u64_stats_add(&stats->tx_bytes, ret); - u64_stats_update_end(&stats->syncp); - put_cpu_ptr(tun->pcpu_stats); + preempt_disable(); + dev_sw_netstats_tx_add(tun->dev, 1, ret); + preempt_enable(); return ret; } @@ -2013,7 +1969,6 @@ static ssize_t tun_put_user(struct tun_struct *tun, struct iov_iter *iter) { struct tun_pi pi = { 0, skb->protocol }; - struct tun_pcpu_stats *stats; ssize_t total; int vlan_offset = 0; int vlan_hlen = 0; @@ -2091,12 +2046,9 @@ static ssize_t tun_put_user(struct tun_struct *tun, done: /* caller is in process context, */ - stats = get_cpu_ptr(tun->pcpu_stats); - u64_stats_update_begin(&stats->syncp); - u64_stats_inc(&stats->tx_packets); - u64_stats_add(&stats->tx_bytes, skb->len + vlan_hlen); - u64_stats_update_end(&stats->syncp); - put_cpu_ptr(tun->pcpu_stats); + preempt_disable(); + dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen); + preempt_enable(); return total; } @@ -2235,11 +2187,11 @@ static void tun_free_netdev(struct net_device *dev) BUG_ON(!(list_empty(&tun->disabled))); - free_percpu(tun->pcpu_stats); - /* We clear pcpu_stats so that tun_set_iff() can tell if + free_percpu(dev->tstats); + /* We clear tstats so that tun_set_iff() can tell if * tun_free_netdev() has been called from register_netdevice(). */ - tun->pcpu_stats = NULL; + dev->tstats = NULL; tun_flow_uninit(tun); security_tun_dev_free_security(tun->security); @@ -2370,7 +2322,6 @@ static int tun_xdp_one(struct tun_struct *tun, unsigned int datasize = xdp->data_end - xdp->data; struct tun_xdp_hdr *hdr = xdp->data_hard_start; struct virtio_net_hdr *gso = &hdr->gso; - struct tun_pcpu_stats *stats; struct bpf_prog *xdp_prog; struct sk_buff *skb = NULL; u32 rxhash = 0, act; @@ -2428,7 +2379,7 @@ static int tun_xdp_one(struct tun_struct *tun, skb_put(skb, xdp->data_end - xdp->data); if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) { - this_cpu_inc(tun->pcpu_stats->rx_frame_errors); + atomic_long_inc(&tun->rx_frame_errors); kfree_skb(skb); err = -EINVAL; goto out; @@ -2451,14 +2402,10 @@ static int tun_xdp_one(struct tun_struct *tun, netif_receive_skb(skb); - /* No need for get_cpu_ptr() here since this function is + /* No need to disable preemption here since this function is * always called with bh disabled */ - stats = this_cpu_ptr(tun->pcpu_stats); - u64_stats_update_begin(&stats->syncp); - u64_stats_inc(&stats->rx_packets); - u64_stats_add(&stats->rx_bytes, datasize); - u64_stats_update_end(&stats->syncp); + dev_sw_netstats_rx_add(tun->dev, datasize); if (rxhash) tun_flow_update(tun, rxhash, tfile); @@ -2751,8 +2698,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) tun->rx_batched = 0; RCU_INIT_POINTER(tun->steering_prog, NULL); - tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats); - if (!tun->pcpu_stats) { + dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); + if (!dev->tstats) { err = -ENOMEM; goto err_free_dev; } @@ -2807,16 +2754,16 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) tun_detach_all(dev); /* We are here because register_netdevice() has failed. * If register_netdevice() already called tun_free_netdev() - * while dealing with the error, tun->pcpu_stats has been cleared. + * while dealing with the error, dev->stats has been cleared. */ - if (!tun->pcpu_stats) + if (!dev->tstats) goto err_free_dev; err_free_flow: tun_flow_uninit(tun); security_tun_dev_free_security(tun->security); err_free_stat: - free_percpu(tun->pcpu_stats); + free_percpu(dev->tstats); err_free_dev: free_netdev(dev); return err; -- 2.29.2