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 dafa1cb..4dc6641 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -417,7 +417,7 @@ void tcp_update_metrics(struct sock *sk);
 void tcp_init_metrics(struct sock *sk);
 void tcp_metrics_init(void);
 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst,
-                       bool paws_check);
+                       bool paws_check, bool timestamps);
 bool tcp_remember_stamp(struct sock *sk);
 bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw);
 void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst);
@@ -448,6 +448,7 @@ const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
  */
 
 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
+void tcp_v4_mtu_reduced(struct sock *sk);
 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 struct sock *tcp_create_openreq_child(struct sock *sk,
                                      struct request_sock *req,
@@ -671,6 +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
@@ -689,15 +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.   */
@@ -705,12 +706,20 @@ struct tcp_skb_cb {
 #define TCPCB_SACKED_RETRANS   0x02    /* SKB retransmitted            */
 #define TCPCB_LOST             0x04    /* SKB is lost                  */
 #define TCPCB_TAGBITS          0x07    /* All tag bits                 */
+#define TCPCB_REPAIRED         0x10    /* SKB repaired (no skb_mstamp) */
 #define TCPCB_EVER_RETRANS     0x80    /* Ever retransmitted frame     */
-#define TCPCB_RETRANS          (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS)
+#define TCPCB_RETRANS          (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \
+                               TCPCB_REPAIRED)
 
        __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]))