ixgbe: Address fact that RSC was not setting GSO size for incoming frames
This patch is meant to address the fact that RSC has not been setting the gso_size value on the skb. As a result performance on lossy TCP connections was negatively impacted. This change resolves the issue by setting gso_size to the average size for incoming packets. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Tested-by: Stephen Ko <stephen.s.ko@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Alexander Duyck
Jeff Kirsher
parent
4c1975d77b
commit
1d2024f61e
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@ -1276,6 +1276,104 @@ static inline bool ixgbe_close_active_frag_list(struct sk_buff *head)
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return true;
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}
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/**
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* ixgbe_get_headlen - determine size of header for RSC/LRO/GRO/FCOE
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* @data: pointer to the start of the headers
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* @max_len: total length of section to find headers in
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*
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* This function is meant to determine the length of headers that will
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* be recognized by hardware for LRO, GRO, and RSC offloads. The main
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* motivation of doing this is to only perform one pull for IPv4 TCP
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* packets so that we can do basic things like calculating the gso_size
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* based on the average data per packet.
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**/
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static unsigned int ixgbe_get_headlen(unsigned char *data,
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unsigned int max_len)
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{
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union {
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unsigned char *network;
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/* l2 headers */
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struct ethhdr *eth;
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struct vlan_hdr *vlan;
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/* l3 headers */
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struct iphdr *ipv4;
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} hdr;
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__be16 protocol;
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u8 nexthdr = 0; /* default to not TCP */
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u8 hlen;
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/* this should never happen, but better safe than sorry */
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if (max_len < ETH_HLEN)
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return max_len;
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/* initialize network frame pointer */
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hdr.network = data;
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/* set first protocol and move network header forward */
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protocol = hdr.eth->h_proto;
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hdr.network += ETH_HLEN;
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/* handle any vlan tag if present */
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if (protocol == __constant_htons(ETH_P_8021Q)) {
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if ((hdr.network - data) > (max_len - VLAN_HLEN))
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return max_len;
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protocol = hdr.vlan->h_vlan_encapsulated_proto;
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hdr.network += VLAN_HLEN;
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}
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/* handle L3 protocols */
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if (protocol == __constant_htons(ETH_P_IP)) {
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if ((hdr.network - data) > (max_len - sizeof(struct iphdr)))
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return max_len;
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/* access ihl as a u8 to avoid unaligned access on ia64 */
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hlen = (hdr.network[0] & 0x0F) << 2;
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/* verify hlen meets minimum size requirements */
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if (hlen < sizeof(struct iphdr))
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return hdr.network - data;
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/* record next protocol */
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nexthdr = hdr.ipv4->protocol;
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hdr.network += hlen;
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#ifdef CONFIG_FCOE
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} else if (protocol == __constant_htons(ETH_P_FCOE)) {
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if ((hdr.network - data) > (max_len - FCOE_HEADER_LEN))
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return max_len;
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hdr.network += FCOE_HEADER_LEN;
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#endif
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} else {
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return hdr.network - data;
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}
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/* finally sort out TCP */
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if (nexthdr == IPPROTO_TCP) {
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if ((hdr.network - data) > (max_len - sizeof(struct tcphdr)))
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return max_len;
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/* access doff as a u8 to avoid unaligned access on ia64 */
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hlen = (hdr.network[12] & 0xF0) >> 2;
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/* verify hlen meets minimum size requirements */
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if (hlen < sizeof(struct tcphdr))
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return hdr.network - data;
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hdr.network += hlen;
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}
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/*
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* If everything has gone correctly hdr.network should be the
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* data section of the packet and will be the end of the header.
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* If not then it probably represents the end of the last recognized
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* header.
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*/
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if ((hdr.network - data) < max_len)
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return hdr.network - data;
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else
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return max_len;
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}
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static void ixgbe_get_rsc_cnt(struct ixgbe_ring *rx_ring,
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union ixgbe_adv_rx_desc *rx_desc,
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struct sk_buff *skb)
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@ -1299,6 +1397,32 @@ static void ixgbe_get_rsc_cnt(struct ixgbe_ring *rx_ring,
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IXGBE_CB(skb)->append_cnt += rsc_cnt - 1;
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}
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static void ixgbe_set_rsc_gso_size(struct ixgbe_ring *ring,
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struct sk_buff *skb)
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{
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u16 hdr_len = ixgbe_get_headlen(skb->data, skb_headlen(skb));
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/* set gso_size to avoid messing up TCP MSS */
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skb_shinfo(skb)->gso_size = DIV_ROUND_UP((skb->len - hdr_len),
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IXGBE_CB(skb)->append_cnt);
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}
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static void ixgbe_update_rsc_stats(struct ixgbe_ring *rx_ring,
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struct sk_buff *skb)
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{
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/* if append_cnt is 0 then frame is not RSC */
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if (!IXGBE_CB(skb)->append_cnt)
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return;
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rx_ring->rx_stats.rsc_count += IXGBE_CB(skb)->append_cnt;
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rx_ring->rx_stats.rsc_flush++;
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ixgbe_set_rsc_gso_size(rx_ring, skb);
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/* gso_size is computed using append_cnt so always clear it last */
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IXGBE_CB(skb)->append_cnt = 0;
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}
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static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
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struct ixgbe_ring *rx_ring,
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int budget)
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@ -1437,11 +1561,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
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goto next_desc;
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}
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if (IXGBE_CB(skb)->append_cnt) {
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rx_ring->rx_stats.rsc_count +=
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IXGBE_CB(skb)->append_cnt;
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rx_ring->rx_stats.rsc_flush++;
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}
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ixgbe_update_rsc_stats(rx_ring, skb);
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/* ERR_MASK will only have valid bits if EOP set */
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if (unlikely(staterr & IXGBE_RXDADV_ERR_FRAME_ERR_MASK)) {
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