diff options
| -rw-r--r-- | include/linux/tcp.h | 2 | ||||
| -rw-r--r-- | include/net/tcp.h | 4 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 26 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 10 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 578 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 2 |
7 files changed, 384 insertions, 240 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index dfd93d03f5d2..e4fd82e42104 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -286,7 +286,7 @@ struct tcp_sock { __u32 max_window; /* Maximal window ever seen from peer */ __u32 pmtu_cookie; /* Last pmtu seen by socket */ __u32 mss_cache; /* Cached effective mss, not including SACKS */ - __u16 mss_cache_std; /* Like mss_cache, but without TSO */ + __u16 xmit_size_goal; /* Goal for segmenting output packets */ __u16 ext_header_len; /* Network protocol overhead (IP/IPv6 options) */ __u8 ca_state; /* State of fast-retransmit machine */ __u8 retransmits; /* Number of unrecovered RTO timeouts. */ diff --git a/include/net/tcp.h b/include/net/tcp.h index b19238027da8..a166918ca56d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -862,7 +862,7 @@ extern int tcp_write_wakeup(struct sock *); extern void tcp_send_fin(struct sock *sk); extern void tcp_send_active_reset(struct sock *sk, int priority); extern int tcp_send_synack(struct sock *); -extern void tcp_push_one(struct sock *, unsigned mss_now); +extern void tcp_push_one(struct sock *, unsigned int mss_now); extern void tcp_send_ack(struct sock *sk); extern void tcp_send_delayed_ack(struct sock *sk); @@ -968,7 +968,7 @@ static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long static inline void tcp_initialize_rcv_mss(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); - unsigned int hint = min(tp->advmss, tp->mss_cache_std); + unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); hint = min(hint, tp->rcv_wnd/2); hint = min(hint, TCP_MIN_RCVMSS); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2ba73bf3a8f9..29894c749163 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -615,7 +615,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffse size_t psize, int flags) { struct tcp_sock *tp = tcp_sk(sk); - int mss_now; + int mss_now, size_goal; int err; ssize_t copied; long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); @@ -628,6 +628,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffse clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); + size_goal = tp->xmit_size_goal; copied = 0; err = -EPIPE; @@ -641,7 +642,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffse int offset = poffset % PAGE_SIZE; int size = min_t(size_t, psize, PAGE_SIZE - offset); - if (!sk->sk_send_head || (copy = mss_now - skb->len) <= 0) { + if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) { new_segment: if (!sk_stream_memory_free(sk)) goto wait_for_sndbuf; @@ -652,7 +653,7 @@ new_segment: goto wait_for_memory; skb_entail(sk, tp, skb); - copy = mss_now; + copy = size_goal; } if (copy > size) @@ -693,7 +694,7 @@ new_segment: if (!(psize -= copy)) goto out; - if (skb->len != mss_now || (flags & MSG_OOB)) + if (skb->len < mss_now || (flags & MSG_OOB)) continue; if (forced_push(tp)) { @@ -713,6 +714,7 @@ wait_for_memory: goto do_error; mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); + size_goal = tp->xmit_size_goal; } out: @@ -754,7 +756,7 @@ ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, static inline int select_size(struct sock *sk, struct tcp_sock *tp) { - int tmp = tp->mss_cache_std; + int tmp = tp->mss_cache; if (sk->sk_route_caps & NETIF_F_SG) { if (sk->sk_route_caps & NETIF_F_TSO) @@ -778,7 +780,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; int iovlen, flags; - int mss_now; + int mss_now, size_goal; int err, copied; long timeo; @@ -797,6 +799,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); + size_goal = tp->xmit_size_goal; /* Ok commence sending. */ iovlen = msg->msg_iovlen; @@ -819,7 +822,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, skb = sk->sk_write_queue.prev; if (!sk->sk_send_head || - (copy = mss_now - skb->len) <= 0) { + (copy = size_goal - skb->len) <= 0) { new_segment: /* Allocate new segment. If the interface is SG, @@ -842,7 +845,7 @@ new_segment: skb->ip_summed = CHECKSUM_HW; skb_entail(sk, tp, skb); - copy = mss_now; + copy = size_goal; } /* Try to append data to the end of skb. */ @@ -937,7 +940,7 @@ new_segment: if ((seglen -= copy) == 0 && iovlen == 0) goto out; - if (skb->len != mss_now || (flags & MSG_OOB)) + if (skb->len < mss_now || (flags & MSG_OOB)) continue; if (forced_push(tp)) { @@ -957,6 +960,7 @@ wait_for_memory: goto do_error; mss_now = tcp_current_mss(sk, !(flags&MSG_OOB)); + size_goal = tp->xmit_size_goal; } } @@ -2128,7 +2132,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) info->tcpi_rto = jiffies_to_usecs(tp->rto); info->tcpi_ato = jiffies_to_usecs(tp->ack.ato); - info->tcpi_snd_mss = tp->mss_cache_std; + info->tcpi_snd_mss = tp->mss_cache; info->tcpi_rcv_mss = tp->ack.rcv_mss; info->tcpi_unacked = tp->packets_out; @@ -2178,7 +2182,7 @@ int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, switch (optname) { case TCP_MAXSEG: - val = tp->mss_cache_std; + val = tp->mss_cache; if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) val = tp->rx_opt.user_mss; break; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 2ef2f355b8b8..8de2f1071c2b 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -740,10 +740,10 @@ __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst) __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); if (!cwnd) { - if (tp->mss_cache_std > 1460) + if (tp->mss_cache > 1460) cwnd = 2; else - cwnd = (tp->mss_cache_std > 1095) ? 3 : 4; + cwnd = (tp->mss_cache > 1095) ? 3 : 4; } return min_t(__u32, cwnd, tp->snd_cwnd_clamp); } @@ -914,7 +914,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ if (sk->sk_route_caps & NETIF_F_TSO) { sk->sk_route_caps &= ~NETIF_F_TSO; sock_set_flag(sk, SOCK_NO_LARGESEND); - tp->mss_cache = tp->mss_cache_std; + tp->mss_cache = tp->mss_cache; } if (!tp->sacked_out) @@ -1077,7 +1077,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ (IsFack(tp) || !before(lost_retrans, TCP_SKB_CB(skb)->ack_seq + tp->reordering * - tp->mss_cache_std))) { + tp->mss_cache))) { TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS; tp->retrans_out -= tcp_skb_pcount(skb); @@ -3334,7 +3334,7 @@ static void tcp_new_space(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); if (tcp_should_expand_sndbuf(sk, tp)) { - int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache_std) + + int sndmem = max_t(u32, tp->rx_opt.mss_clamp, tp->mss_cache) + MAX_TCP_HEADER + 16 + sizeof(struct sk_buff), demanded = max_t(unsigned int, tp->snd_cwnd, tp->reordering + 1); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index ebf112347a97..62f62bb05c2a 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2045,7 +2045,7 @@ static int tcp_v4_init_sock(struct sock *sk) */ tp->snd_ssthresh = 0x7fffffff; /* Infinity */ tp->snd_cwnd_clamp = ~0; - tp->mss_cache_std = tp->mss_cache = 536; + tp->mss_cache = 536; tp->reordering = sysctl_tcp_reordering; tp->ca_ops = &tcp_init_congestion_ops; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0a4cd24b6578..fd3ce38184ae 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -49,7 +49,7 @@ int sysctl_tcp_retrans_collapse = 1; * will allow a single TSO frame to consume. Building TSO frames * which are too large can cause TCP streams to be bursty. */ -int sysctl_tcp_tso_win_divisor = 8; +int sysctl_tcp_tso_win_divisor = 3; static inline void update_send_head(struct sock *sk, struct tcp_sock *tp, struct sk_buff *skb) @@ -403,21 +403,11 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb) sk->sk_send_head = skb; } -static inline void tcp_tso_set_push(struct sk_buff *skb) -{ - /* Force push to be on for any TSO frames to workaround - * problems with busted implementations like Mac OS-X that - * hold off socket receive wakeups until push is seen. - */ - if (tcp_skb_pcount(skb) > 1) - TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; -} - static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); - if (skb->len <= tp->mss_cache_std || + if (skb->len <= tp->mss_cache || !(sk->sk_route_caps & NETIF_F_TSO)) { /* Avoid the costly divide in the normal * non-TSO case. @@ -427,164 +417,10 @@ static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb) } else { unsigned int factor; - factor = skb->len + (tp->mss_cache_std - 1); - factor /= tp->mss_cache_std; + factor = skb->len + (tp->mss_cache - 1); + factor /= tp->mss_cache; skb_shinfo(skb)->tso_segs = factor; - skb_shinfo(skb)->tso_size = tp->mss_cache_std; - } -} - -/* Does SKB fit into the send window? */ -static inline int tcp_snd_wnd_test(struct tcp_sock *tp, struct sk_buff *skb, unsigned int cur_mss) -{ - u32 end_seq = TCP_SKB_CB(skb)->end_seq; - - return !after(end_seq, tp->snd_una + tp->snd_wnd); -} - -/* Can at least one segment of SKB be sent right now, according to the - * congestion window rules? If so, return how many segments are allowed. - */ -static inline unsigned int tcp_cwnd_test(struct tcp_sock *tp, struct sk_buff *skb) -{ - u32 in_flight, cwnd; - - /* Don't be strict about the congestion window for the final FIN. */ - if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) - return 1; - - in_flight = tcp_packets_in_flight(tp); - cwnd = tp->snd_cwnd; - if (in_flight < cwnd) - return (cwnd - in_flight); - - return 0; -} - -static inline int tcp_minshall_check(const struct tcp_sock *tp) -{ - return after(tp->snd_sml,tp->snd_una) && - !after(tp->snd_sml, tp->snd_nxt); -} - -/* Return 0, if packet can be sent now without violation Nagle's rules: - * 1. It is full sized. - * 2. Or it contains FIN. (already checked by caller) - * 3. Or TCP_NODELAY was set. - * 4. Or TCP_CORK is not set, and all sent packets are ACKed. - * With Minshall's modification: all sent small packets are ACKed. - */ - -static inline int tcp_nagle_check(const struct tcp_sock *tp, - const struct sk_buff *skb, - unsigned mss_now, int nonagle) -{ - return (skb->len < mss_now && - ((nonagle&TCP_NAGLE_CORK) || - (!nonagle && - tp->packets_out && - tcp_minshall_check(tp)))); -} - -/* Return non-zero if the Nagle test allows this packet to be - * sent now. - */ -static inline int tcp_nagle_test(struct tcp_sock *tp, struct sk_buff *skb, - unsigned int cur_mss, int nonagle) -{ - /* Nagle rule does not apply to frames, which sit in the middle of the - * write_queue (they have no chances to get new data). - * - * This is implemented in the callers, where they modify the 'nonagle' - * argument based upon the location of SKB in the send queue. - */ - if (nonagle & TCP_NAGLE_PUSH) - return 1; - - /* Don't use the nagle rule for urgent data (or for the final FIN). */ - if (tp->urg_mode || - (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)) - return 1; - - if (!tcp_nagle_check(tp, skb, cur_mss, nonagle)) - return 1; - - return 0; -} - -/* This must be invoked the first time we consider transmitting - * SKB onto the wire. - */ -static inline int tcp_init_tso_segs(struct sock *sk, struct sk_buff *skb) -{ - int tso_segs = tcp_skb_pcount(skb); - - if (!tso_segs) { - tcp_set_skb_tso_segs(sk, skb); - tso_segs = tcp_skb_pcount(skb); - } - return tso_segs; -} - -/* This checks if the data bearing packet SKB (usually sk->sk_send_head) - * should be put on the wire right now. If so, it returns the number of - * packets allowed by the congestion window. - */ -static unsigned int tcp_snd_test(struct sock *sk, struct sk_buff *skb, - unsigned int cur_mss, int nonagle) -{ - struct tcp_sock *tp = tcp_sk(sk); - unsigned int cwnd_quota; - - tcp_init_tso_segs(sk, skb); - - if (!tcp_nagle_test(tp, skb, cur_mss, nonagle)) - return 0; - - cwnd_quota = tcp_cwnd_test(tp, skb); - if (cwnd_quota && - !tcp_snd_wnd_test(tp, skb, cur_mss)) - cwnd_quota = 0; - - return cwnd_quota; -} - -static inline int tcp_skb_is_last(const struct sock *sk, - const struct sk_buff *skb) -{ - return skb->next == (struct sk_buff *)&sk->sk_write_queue; -} - -int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp) -{ - struct sk_buff *skb = sk->sk_send_head; - - return (skb && - tcp_snd_test(sk, skb, tcp_current_mss(sk, 1), - (tcp_skb_is_last(sk, skb) ? - TCP_NAGLE_PUSH : - tp->nonagle))); -} - - -/* Send _single_ skb sitting at the send head. This function requires - * true push pending frames to setup probe timer etc. - */ -void tcp_push_one(struct sock *sk, unsigned cur_mss) -{ - struct tcp_sock *tp = tcp_sk(sk); - struct sk_buff *skb = sk->sk_send_head; - - if (tcp_snd_test(sk, skb, cur_mss, TCP_NAGLE_PUSH)) { - /* Send it out now. */ - TCP_SKB_CB(skb)->when = tcp_time_stamp; - tcp_tso_set_push(skb); - if (!tcp_transmit_skb(sk, skb_clone(skb, sk->sk_allocation))) { - sk->sk_send_head = NULL; - tp->snd_nxt = TCP_SKB_CB(skb)->end_seq; - tcp_packets_out_inc(sk, tp, skb); - return; - } + skb_shinfo(skb)->tso_size = tp->mss_cache; } } @@ -791,7 +627,7 @@ unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu) /* And store cached results */ tp->pmtu_cookie = pmtu; - tp->mss_cache = tp->mss_cache_std = mss_now; + tp->mss_cache = mss_now; return mss_now; } @@ -803,56 +639,47 @@ unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu) * cannot be large. However, taking into account rare use of URG, this * is not a big flaw. */ - -unsigned int tcp_current_mss(struct sock *sk, int large) +unsigned int tcp_current_mss(struct sock *sk, int large_allowed) { struct tcp_sock *tp = tcp_sk(sk); struct dst_entry *dst = __sk_dst_get(sk); - unsigned int do_large, mss_now; + u32 mss_now; + u16 xmit_size_goal; + int doing_tso = 0; + + mss_now = tp->mss_cache; + + if (large_allowed && + (sk->sk_route_caps & NETIF_F_TSO) && + !tp->urg_mode) + doing_tso = 1; - mss_now = tp->mss_cache_std; if (dst) { u32 mtu = dst_mtu(dst); if (mtu != tp->pmtu_cookie) mss_now = tcp_sync_mss(sk, mtu); } - do_large = (large && - (sk->sk_route_caps & NETIF_F_TSO) && - !tp->urg_mode); + if (tp->rx_opt.eff_sacks) + mss_now -= (TCPOLEN_SACK_BASE_ALIGNED + + (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK)); - if (do_large) { - unsigned int large_mss, factor, limit; + xmit_size_goal = mss_now; - large_mss = 65535 - tp->af_specific->net_header_len - + if (doing_tso) { + xmit_size_goal = 65535 - + tp->af_specific->net_header_len - tp->ext_header_len - tp->tcp_header_len; - if (tp->max_window && large_mss > (tp->max_window>>1)) - large_mss = max((tp->max_window>>1), - 68U - tp->tcp_header_len); - - factor = large_mss / mss_now; + if (tp->max_window && + (xmit_size_goal > (tp->max_window >> 1))) + xmit_size_goal = max((tp->max_window >> 1), + 68U - tp->tcp_header_len); - /* Always keep large mss multiple of real mss, but - * do not exceed 1/tso_win_divisor of the congestion window - * so we can keep the ACK clock ticking and minimize - * bursting. - */ - limit = tp->snd_cwnd; - if (sysctl_tcp_tso_win_divisor) - limit /= sysctl_tcp_tso_win_divisor; - limit = max(1U, limit); - if (factor > limit) - factor = limit; - - tp->mss_cache = mss_now * factor; - - mss_now = tp->mss_cache; + xmit_size_goal -= (xmit_size_goal % mss_now); } + tp->xmit_size_goal = xmit_size_goal; - if (tp->rx_opt.eff_sacks) - mss_now -= (TCPOLEN_SACK_BASE_ALIGNED + - (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK)); return mss_now; } @@ -876,6 +703,251 @@ static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp) } } +static unsigned int tcp_window_allows(struct tcp_sock *tp, struct sk_buff *skb, unsigned int mss_now, unsigned int cwnd) +{ + u32 window, cwnd_len; + + window = (tp->snd_una + tp->snd_wnd - TCP_SKB_CB(skb)->seq); + cwnd_len = mss_now * cwnd; + return min(window, cwnd_len); +} + +/* Can at least one segment of SKB be sent right now, according to the + * congestion window rules? If so, return how many segments are allowed. + */ +static inline unsigned int tcp_cwnd_test(struct tcp_sock *tp, struct sk_buff *skb) +{ + u32 in_flight, cwnd; + + /* Don't be strict about the congestion window for the final FIN. */ + if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) + return 1; + + in_flight = tcp_packets_in_flight(tp); + cwnd = tp->snd_cwnd; + if (in_flight < cwnd) + return (cwnd - in_flight); + + return 0; +} + +/* This must be invoked the first time we consider transmitting + * SKB onto the wire. + */ +static inline int tcp_init_tso_segs(struct sock *sk, struct sk_buff *skb) +{ + int tso_segs = tcp_skb_pcount(skb); + + if (!tso_segs) { + tcp_set_skb_tso_segs(sk, skb); + tso_segs = tcp_skb_pcount(skb); + } + return tso_segs; +} + +static inline int tcp_minshall_check(const struct tcp_sock *tp) +{ + return after(tp->snd_sml,tp->snd_una) && + !after(tp->snd_sml, tp->snd_nxt); +} + +/* Return 0, if packet can be sent now without violation Nagle's rules: + * 1. It is full sized. + * 2. Or it contains FIN. (already checked by caller) + * 3. Or TCP_NODELAY was set. + * 4. Or TCP_CORK is not set, and all sent packets are ACKed. + * With Minshall's modification: all sent small packets are ACKed. + */ + +static inline int tcp_nagle_check(const struct tcp_sock *tp, + const struct sk_buff *skb, + unsigned mss_now, int nonagle) +{ + return (skb->len < mss_now && + ((nonagle&TCP_NAGLE_CORK) || + (!nonagle && + tp->packets_out && + tcp_minshall_check(tp)))); +} + +/* Return non-zero if the Nagle test allows this packet to be + * sent now. + */ +static inline int tcp_nagle_test(struct tcp_sock *tp, struct sk_buff *skb, + unsigned int cur_mss, int nonagle) +{ + /* Nagle rule does not apply to frames, which sit in the middle of the + * write_queue (they have no chances to get new data). + * + * This is implemented in the callers, where they modify the 'nonagle' + * argument based upon the location of SKB in the send queue. + */ + if (nonagle & TCP_NAGLE_PUSH) + return 1; + + /* Don't use the nagle rule for urgent data (or for the final FIN). */ + if (tp->urg_mode || + (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)) + return 1; + + if (!tcp_nagle_check(tp, skb, cur_mss, nonagle)) + return 1; + + return 0; +} + +/* Does at least the first segment of SKB fit into the send window? */ +static inline int tcp_snd_wnd_test(struct tcp_sock *tp, struct sk_buff *skb, unsigned int cur_mss) +{ + u32 end_seq = TCP_SKB_CB(skb)->end_seq; + + if (skb->len > cur_mss) + end_seq = TCP_SKB_CB(skb)->seq + cur_mss; + + return !after(end_seq, tp->snd_una + tp->snd_wnd); +} + +/* This checks if the data bearing packet SKB (usually sk->sk_send_head) + * should be put on the wire right now. If so, it returns the number of + * packets allowed by the congestion window. + */ +static unsigned int tcp_snd_test(struct sock *sk, struct sk_buff *skb, + unsigned int cur_mss, int nonagle) +{ + struct tcp_sock *tp = tcp_sk(sk); + unsigned int cwnd_quota; + + tcp_init_tso_segs(sk, skb); + + if (!tcp_nagle_test(tp, skb, cur_mss, nonagle)) + return 0; + + cwnd_quota = tcp_cwnd_test(tp, skb); + if (cwnd_quota && + !tcp_snd_wnd_test(tp, skb, cur_mss)) + cwnd_quota = 0; + + return cwnd_quota; +} + +static inline int tcp_skb_is_last(const struct sock *sk, + const struct sk_buff *skb) +{ + return skb->next == (struct sk_buff *)&sk->sk_write_queue; +} + +int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp) +{ + struct sk_buff *skb = sk->sk_send_head; + + return (skb && + tcp_snd_test(sk, skb, tcp_current_mss(sk, 1), + (tcp_skb_is_last(sk, skb) ? + TCP_NAGLE_PUSH : + tp->nonagle))); +} + +/* Trim TSO SKB to LEN bytes, put the remaining data into a new packet + * which is put after SKB on the list. It is very much like + * tcp_fragment() except that it may make several kinds of assumptions + * in order to speed up the splitting operation. In particular, we + * know that all the data is in scatter-gather pages, and that the + * packet has never been sent out before (and thus is not cloned). + */ +static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len) +{ + struct sk_buff *buff; + int nlen = skb->len - len; + u16 flags; + + /* All of a TSO frame must be composed of paged data. */ + BUG_ON(skb->len != skb->data_len); + + buff = sk_stream_alloc_pskb(sk, 0, 0, GFP_ATOMIC); + if (unlikely(buff == NULL)) + return -ENOMEM; + + buff->truesize = nlen; + skb->truesize -= nlen; + + /* Correct the sequence numbers. */ + TCP_SKB_CB(buff)->seq = TCP_SKB_CB(skb)->seq + len; + TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq; + TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq; + + /* PSH and FIN should only be set in the second packet. */ + flags = TCP_SKB_CB(skb)->flags; + TCP_SKB_CB(skb)->flags = flags & ~(TCPCB_FLAG_FIN|TCPCB_FLAG_PSH); + TCP_SKB_CB(buff)->flags = flags; + + /* This packet was never sent out yet, so no SACK bits. */ + TCP_SKB_CB(buff)->sacked = 0; + + buff->ip_summed = skb->ip_summed = CHECKSUM_HW; + skb_split(skb, buff, len); + + /* Fix up tso_factor for both original and new SKB. */ + tcp_set_skb_tso_segs(sk, skb); + tcp_set_skb_tso_segs(sk, buff); + + /* Link BUFF into the send queue. */ + skb_header_release(buff); + __skb_append(skb, buff); + + return 0; +} + +/* Try to defer sending, if possible, in order to minimize the amount + * of TSO splitting we do. View it as a kind of TSO Nagle test. + * + * This algorithm is from John Heffner. + */ +static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_buff *skb) +{ + u32 send_win, cong_win, limit, in_flight; + + if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN) + return 0; + + in_flight = tcp_packets_in_flight(tp); + + BUG_ON(tcp_skb_pcount(skb) <= 1 || + (tp->snd_cwnd <= in_flight)); + + send_win = (tp->snd_una + tp->snd_wnd) - TCP_SKB_CB(skb)->seq; + + /* From in_flight test above, we know that cwnd > in_flight. */ + cong_win = (tp->snd_cwnd - in_flight) * tp->mss_cache; + + limit = min(send_win, cong_win); + + /* If sk_send_head can be sent fully now, just do it. */ + if (skb->len <= limit) + return 0; + + if (sysctl_tcp_tso_win_divisor) { + u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache); + + /* If at least some fraction of a window is available, + * just use it. + */ + chunk /= sysctl_tcp_tso_win_divisor; + if (limit >= chunk) + return 0; + } else { + /* Different approach, try not to defer past a single + * ACK. Receiver should ACK every other full sized + * frame, so if we have space for more than 3 frames + * then send now. + */ + if (limit > tcp_max_burst(tp) * tp->mss_cache) + return 0; + } + + /* Ok, it looks like it is advisable to defer. */ + return 1; +} + /* This routine writes packets to the network. It advances the * send_head. This happens as incoming acks open up the remote * window for us. @@ -887,8 +959,8 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; - unsigned int tso_segs, cwnd_quota; - int sent_pkts; + unsigned int tso_segs, sent_pkts; + int cwnd_quota; /* If we are closed, the bytes will have to remain here. * In time closedown will finish, we empty the write queue and all @@ -903,24 +975,44 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle) tso_segs = tcp_init_tso_segs(sk, skb); cwnd_quota = tcp_cwnd_test(tp, skb); + if (unlikely(!cwnd_quota)) + goto out; + sent_pkts = 0; + while (likely(tcp_snd_wnd_test(tp, skb, mss_now))) { + BUG_ON(!tso_segs); - while (cwnd_quota >= tso_segs) { - if (unlikely(!tcp_nagle_test(tp, skb, mss_now, - (tcp_skb_is_last(sk, skb) ? - nonagle : TCP_NAGLE_PUSH)))) - break; + if (tso_segs == 1) { + if (unlikely(!tcp_nagle_test(tp, skb, mss_now, + (tcp_skb_is_last(sk, skb) ? + nonagle : TCP_NAGLE_PUSH)))) + break; + } else { + if (tcp_tso_should_defer(sk, tp, skb)) + break; + } - if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now))) - break; + if (tso_segs > 1) { + u32 limit = tcp_window_allows(tp, skb, + mss_now, cwnd_quota); + + if (skb->len < limit) { + unsigned int trim = skb->len % mss_now; - if (unlikely(skb->len > mss_now)) { + if (trim) + limit = skb->len - trim; + } + if (skb->len > limit) { + if (tso_fragment(sk, skb, limit)) + break; + } + } else if (unlikely(skb->len > mss_now)) { if (unlikely(tcp_fragment(sk, skb, mss_now))) break; } TCP_SKB_CB(skb)->when = tcp_time_stamp; - tcp_tso_set_push(skb); + if (unlikely(tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC)))) break; @@ -936,6 +1028,11 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle) * the packet above, tso_segs will no longer be valid. */ cwnd_quota -= tcp_skb_pcount(skb); + + BUG_ON(cwnd_quota < 0); + if (!cwnd_quota) + break; + skb = sk->sk_send_head; if (!skb) break; @@ -946,7 +1043,7 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle) tcp_cwnd_validate(sk, tp); return 0; } - +out: return !tp->packets_out && sk->sk_send_head; } @@ -965,6 +1062,53 @@ void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, } } +/* Send _single_ skb sitting at the send head. This function requires + * true push pending frames to setup probe timer etc. + */ +void tcp_push_one(struct sock *sk, unsigned int mss_now) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct sk_buff *skb = sk->sk_send_head; + unsigned int tso_segs, cwnd_quota; + + BUG_ON(!skb || skb->len < mss_now); + + tso_segs = tcp_init_tso_segs(sk, skb); + cwnd_quota = tcp_snd_test(sk, skb, mss_now, TCP_NAGLE_PUSH); + + if (likely(cwnd_quota)) { + BUG_ON(!tso_segs); + + if (tso_segs > 1) { + u32 limit = tcp_window_allows(tp, skb, + mss_now, cwnd_quota); + + if (skb->len < limit) { + unsigned int trim = skb->len % mss_now; + + if (trim) + limit = skb->len - trim; + } + if (skb->len > limit) { + if (unlikely(tso_fragment(sk, skb, limit))) + return; + } + } else if (unlikely(skb->len > mss_now)) { + if (unlikely(tcp_fragment(sk, skb, mss_now))) + return; + } + + /* Send it out now. */ + TCP_SKB_CB(skb)->when = tcp_time_stamp; + + if (likely(!tcp_transmit_skb(sk, skb_clone(skb, sk->sk_allocation)))) { + update_send_head(sk, tp, skb); + tcp_cwnd_validate(sk, tp); + return; + } + } +} + /* This function returns the amount that we can raise the * usable window based on the following constraints * @@ -1222,7 +1366,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb) if (sk->sk_route_caps & NETIF_F_TSO) { sk->sk_route_caps &= ~NETIF_F_TSO; sock_set_flag(sk, SOCK_NO_LARGESEND); - tp->mss_cache = tp->mss_cache_std; } if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq)) @@ -1284,7 +1427,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb) * is still in somebody's hands, else make a clone. */ TCP_SKB_CB(skb)->when = tcp_time_stamp; - tcp_tso_set_push(skb); err = tcp_transmit_skb(sk, (skb_cloned(skb) ? pskb_copy(skb, GFP_ATOMIC): @@ -1853,14 +1995,12 @@ int tcp_write_wakeup(struct sock *sk) if (sk->sk_route_caps & NETIF_F_TSO) { sock_set_flag(sk, SOCK_NO_LARGESEND); sk->sk_route_caps &= ~NETIF_F_TSO; - tp->mss_cache = tp->mss_cache_std; } } else if (!tcp_skb_pcount(skb)) tcp_set_skb_tso_segs(sk, skb); TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH; TCP_SKB_CB(skb)->when = tcp_time_stamp; - tcp_tso_set_push(skb); err = tcp_transmit_skb(sk, skb_clone(skb, GFP_ATOMIC)); if (!err) { update_send_head(sk, tp, skb); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 9dac7fdf4726..f6e288dc116e 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -2018,7 +2018,7 @@ static int tcp_v6_init_sock(struct sock *sk) */ tp->snd_ssthresh = 0x7fffffff; tp->snd_cwnd_clamp = ~0; - tp->mss_cache_std = tp->mss_cache = 536; + tp->mss_cache = 536; tp->reordering = sysctl_tcp_reordering; |