search for: skb_reserv

...); > local_bh_enable(); > @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, > build: > skb = build_skb(buf, buflen); > if (!skb) { > + put_page(alloc_frag->page); > skb = ERR_PTR(-ENOMEM); > goto out; > } > > - skb_reserve(skb, pad - delta); > + skb_reserve(skb, pad); > skb_put(skb, len); > > return skb; > > err_xdp: > - alloc_frag->offset -= buflen; > - put_page(alloc_frag->page); > + this_cpu_inc(tun->pcpu_stats->rx_dropped); This fixes bug in previous patch which...

...); > local_bh_enable(); > @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, > build: > skb = build_skb(buf, buflen); > if (!skb) { > + put_page(alloc_frag->page); > skb = ERR_PTR(-ENOMEM); > goto out; > } > > - skb_reserve(skb, pad - delta); > + skb_reserve(skb, pad); > skb_put(skb, len); > > return skb; > > err_xdp: > - alloc_frag->offset -= buflen; > - put_page(alloc_frag->page); > + this_cpu_inc(tun->pcpu_stats->rx_dropped); This fixes bug in previous patch which...

...len = xdp.data_end - xdp.data; } rcu_read_unlock(); local_bh_enable(); @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, build: skb = build_skb(buf, buflen); if (!skb) { + put_page(alloc_frag->page); skb = ERR_PTR(-ENOMEM); goto out; } - skb_reserve(skb, pad - delta); + skb_reserve(skb, pad); skb_put(skb, len); return skb; err_xdp: - alloc_frag->offset -= buflen; - put_page(alloc_frag->page); + this_cpu_inc(tun->pcpu_stats->rx_dropped); out: rcu_read_unlock(); local_bh_enable(); -- 2.17.1

...18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> build: >> skb = build_skb(buf, buflen); >> if (!skb) { >> + put_page(alloc_frag->page); >> skb = ERR_PTR(-ENOMEM); >> goto out; >> } >> >> - skb_reserve(skb, pad - delta); >> + skb_reserve(skb, pad); >> skb_put(skb, len); >> >> return skb; >> >> err_xdp: >> - alloc_frag->offset -= buflen; >> - put_page(alloc_frag->page); >> + this_cpu_inc(tun->pcpu_stats->rx_dropped);...

Hi: Here are the patches I used for testing KVM with virtio-net using TSO. There are three patches for the tun device which are basically Rusty's patches with the mmap turned into copying (for correctness). Two patches are for the virtio-net frontend, one required to support receiving SG/TSO, and the other useful for testing SG per se. The other patch is to the KVM backend to make all this

Hi: Here are the patches I used for testing KVM with virtio-net using TSO. There are three patches for the tun device which are basically Rusty's patches with the mmap turned into copying (for correctness). Two patches are for the virtio-net frontend, one required to support receiving SG/TSO, and the other useful for testing SG per se. The other patch is to the KVM backend to make all this

Hi all: This series tries to batch submitting packets to underlayer socket through msg_control during sendmsg(). This is done by: 1) Doing userspace copy inside vhost_net 2) Build XDP buff 3) Batch at most 64 (VHOST_NET_BATCH) XDP buffs and submit them once through msg_control during sendmsg(). 4) Underlayer sockets can use XDP buffs directly when XDP is enalbed, or build skb based on XDP

Hi all: This series tries to batch submitting packets to underlayer socket through msg_control during sendmsg(). This is done by: 1) Doing userspace copy inside vhost_net 2) Build XDP buff 3) Batch at most 64 (VHOST_NET_BATCH) XDP buffs and submit them once through msg_control during sendmsg(). 4) Underlayer sockets can use XDP buffs directly when XDP is enalbed, or build skb based on XDP

Hi all: This series tries to batch submitting packets to underlayer socket through msg_control during sendmsg(). This is done by: 1) Doing userspace copy inside vhost_net 2) Build XDP buff 3) Batch at most 64 (VHOST_NET_BATCH) XDP buffs and submit them once through msg_control during sendmsg(). 4) Underlayer sockets can use XDP buffs directly when XDP is enalbed, or build skb based on XDP

...s & IFF_VNET_HDR) > + vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); > + > + skb = build_skb(xdp->data_hard_start, buflen); > + if (!skb) { > + err = -ENOMEM; > + goto err; > + } So fundamentally why is it called XDP? We just build and skb, don't we? > + > + skb_reserve(skb, xdp->data - xdp->data_hard_start); > + skb_put(skb, xdp->data_end - xdp->data); > + > + skb_set_network_header(skb, ETH_HLEN); > + skb_reset_mac_header(skb); > + skb->protocol = eth_hdr(skb)->h_proto; > + > + if (vnet_hdr_len) { > + err = virtio_net_...

1) Turn GSO on virtio net into an all-or-nothing (keep checksumming separate). Having multiple bits is a pain: if you can't support something you should handle it in software, which is still a performance win. 2) Make VIRTIO_NET_HDR_GSO_ECN a flag in the header, so it can apply to IPv6 or v4. 3) Rename VIRTIO_NET_F_NO_CSUM to VIRTIO_NET_F_CSUM (ie. means we do checksumming). 4)

1) Turn GSO on virtio net into an all-or-nothing (keep checksumming separate). Having multiple bits is a pain: if you can't support something you should handle it in software, which is still a performance win. 2) Make VIRTIO_NET_HDR_GSO_ECN a flag in the header, so it can apply to IPv6 or v4. 3) Rename VIRTIO_NET_F_NO_CSUM to VIRTIO_NET_F_CSUM (ie. means we do checksumming). 4)

...skb = build_skb(buf, buflen); > - if (!skb) > - return ERR_PTR(-ENOMEM); > + if (!skb) { > + skb = ERR_PTR(-ENOMEM); > + goto out; So goto out will skip put_page, and we did do get_page above. Seems wrong. You should goto err_skb or something like this. > + } > > skb_reserve(skb, pad - delta); > skb_put(skb, len); > - get_page(alloc_frag->page); > - alloc_frag->offset += buflen; > > return skb; > > -err_redirect: > - put_page(alloc_frag->page); > err_xdp: > + alloc_frag->offset -= buflen; > + put_page(alloc_frag-&g...

...skb = build_skb(buf, buflen); > - if (!skb) > - return ERR_PTR(-ENOMEM); > + if (!skb) { > + skb = ERR_PTR(-ENOMEM); > + goto out; So goto out will skip put_page, and we did do get_page above. Seems wrong. You should goto err_skb or something like this. > + } > > skb_reserve(skb, pad - delta); > skb_put(skb, len); > - get_page(alloc_frag->page); > - alloc_frag->offset += buflen; > > return skb; > > -err_redirect: > - put_page(alloc_frag->page); > err_xdp: > + alloc_frag->offset -= buflen; > + put_page(alloc_frag-&g...

...tio_net_hdr_mrg_rxbuf)) +#define VNET_SKB_OFF VNET_SKB_LEN(VNET_SKB_PAD) + +static struct sk_buff *vnet_build_skb(struct virtnet_info *vi, + void *buf, + unsigned int len, unsigned int truesize) +{ + struct sk_buff *skb = build_skb(buf, truesize); + + if (!skb) + return NULL; + + skb_reserve(skb, VNET_SKB_PAD); + skb_put(skb, VNET_SKB_LEN(len)); + + return skb; +} + static struct sk_buff *receive_mergeable(struct net_device *dev, struct virtnet_info *vi, struct receive_queue *rq, @@ -354,14 +374,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,...

...tio_net_hdr_mrg_rxbuf)) +#define VNET_SKB_OFF VNET_SKB_LEN(VNET_SKB_PAD) + +static struct sk_buff *vnet_build_skb(struct virtnet_info *vi, + void *buf, + unsigned int len, unsigned int truesize) +{ + struct sk_buff *skb = build_skb(buf, truesize); + + if (!skb) + return NULL; + + skb_reserve(skb, VNET_SKB_PAD); + skb_put(skb, VNET_SKB_LEN(len)); + + return skb; +} + static struct sk_buff *receive_mergeable(struct net_device *dev, struct virtnet_info *vi, struct receive_queue *rq, @@ -354,14 +374,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,...

...tun.c @@ -1726,22 +1726,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, goto err_xdp; } } + rcu_read_unlock(); + local_bh_enable(); skb = build_skb(buf, buflen); - if (!skb) { - rcu_read_unlock(); - local_bh_enable(); + if (!skb) return ERR_PTR(-ENOMEM); - } skb_reserve(skb, pad - delta); skb_put(skb, len); get_page(alloc_frag->page); alloc_frag->offset += buflen; - rcu_read_unlock(); - local_bh_enable(); - return skb; err_redirect: -- 2.17.1

...orig_data - xdp.data; len = xdp.data_end - xdp.data; @@ -1730,23 +1725,23 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, local_bh_enable(); skb = build_skb(buf, buflen); - if (!skb) - return ERR_PTR(-ENOMEM); + if (!skb) { + skb = ERR_PTR(-ENOMEM); + goto out; + } skb_reserve(skb, pad - delta); skb_put(skb, len); - get_page(alloc_frag->page); - alloc_frag->offset += buflen; return skb; -err_redirect: - put_page(alloc_frag->page); err_xdp: + alloc_frag->offset -= buflen; + put_page(alloc_frag->page); +out: rcu_read_unlock(); local_bh_enable()...

...n(&np->rx_batch); i < batch_target; i++) { - skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD, + skb = __netdev_alloc_skb(dev, 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); -- 1.6.0.rc0.42.g186458

...n(&np->rx_batch); i < batch_target; i++) { - skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD, + skb = __netdev_alloc_skb(dev, 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); -- 1.5.3 -- yamahata