tcp: better TCP_SKB_CB layout to reduce cache line misses

[cascardo/linux.git] / include / net / tcp.h

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 590e01a..4dc6641 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -672,6 +672,12 @@ void tcp_send_window_probe(struct sock *sk);
  */
 #define tcp_time_stamp         ((__u32)(jiffies))
 
+static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
+{
+       return skb->skb_mstamp.stamp_jiffies;
+}
+
+
 #define tcp_flag_byte(th) (((u_int8_t *)th)[13])
 
 #define TCPHDR_FIN 0x01
@@ -690,15 +696,9 @@ void tcp_send_window_probe(struct sock *sk);
  * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately.
  */
 struct tcp_skb_cb {
-       union {
-               struct inet_skb_parm    h4;
-#if IS_ENABLED(CONFIG_IPV6)
-               struct inet6_skb_parm   h6;
-#endif
-       } header;       /* For incoming frames          */
        __u32           seq;            /* Starting sequence number     */
        __u32           end_seq;        /* SEQ + FIN + SYN + datalen    */
-       __u32           when;           /* used to compute rtt's        */
+       __u32           tcp_tw_isn;     /* isn chosen by tcp_timewait_state_process() */
        __u8            tcp_flags;      /* TCP header flags. (tcp[13])  */
 
        __u8            sacked;         /* State flags for SACK/FACK.   */
@@ -714,6 +714,12 @@ struct tcp_skb_cb {
        __u8            ip_dsfield;     /* IPv4 tos or IPv6 dsfield     */
        /* 1 byte hole */
        __u32           ack_seq;        /* Sequence number ACK'd        */
+       union {
+               struct inet_skb_parm    h4;
+#if IS_ENABLED(CONFIG_IPV6)
+               struct inet6_skb_parm   h6;
+#endif
+       } header;       /* For incoming frames          */
 };
 
 #define TCP_SKB_CB(__skb)      ((struct tcp_skb_cb *)&((__skb)->cb[0]))