From 40b215e594b65a3488576c9d24b367548e18902a Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 3 Jul 2008 01:05:41 -0700 Subject: [PATCH] tcp: de-bloat a bit with factoring NET_INC_STATS_BH out There are some places in TCP that select one MIB index to bump snmp statistics like this: if () NET_INC_STATS_BH(); else if () NET_INC_STATS_BH(); ... else NET_INC_STATS_BH(); or in a more tricky but still similar way. On the other hand, this NET_INC_STATS_BH is a camouflaged increment of percpu variable, which is not that small. Factoring those cases out de-bloats 235 bytes on non-preemptible i386 config and drives parts of the code into 80 columns. add/remove: 0/0 grow/shrink: 0/7 up/down: 0/-235 (-235) function old new delta tcp_fastretrans_alert 1437 1424 -13 tcp_dsack_set 137 124 -13 tcp_xmit_retransmit_queue 690 676 -14 tcp_try_undo_recovery 283 265 -18 tcp_sacktag_write_queue 1550 1515 -35 tcp_update_reordering 162 106 -56 tcp_retransmit_timer 990 904 -86 Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 46 ++++++++++++++++++++++++++++++------------- net/ipv4/tcp_output.c | 7 +++++-- net/ipv4/tcp_timer.c | 15 ++++++++------ 3 files changed, 46 insertions(+), 22 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index de30e70ff256..d6ea970a1513 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -947,17 +947,21 @@ static void tcp_update_reordering(struct sock *sk, const int metric, { struct tcp_sock *tp = tcp_sk(sk); if (metric > tp->reordering) { + int mib_idx; + tp->reordering = min(TCP_MAX_REORDERING, metric); /* This exciting event is worth to be remembered. 8) */ if (ts) - NET_INC_STATS_BH(LINUX_MIB_TCPTSREORDER); + mib_idx = LINUX_MIB_TCPTSREORDER; else if (tcp_is_reno(tp)) - NET_INC_STATS_BH(LINUX_MIB_TCPRENOREORDER); + mib_idx = LINUX_MIB_TCPRENOREORDER; else if (tcp_is_fack(tp)) - NET_INC_STATS_BH(LINUX_MIB_TCPFACKREORDER); + mib_idx = LINUX_MIB_TCPFACKREORDER; else - NET_INC_STATS_BH(LINUX_MIB_TCPSACKREORDER); + mib_idx = LINUX_MIB_TCPSACKREORDER; + + NET_INC_STATS_BH(mib_idx); #if FASTRETRANS_DEBUG > 1 printk(KERN_DEBUG "Disorder%d %d %u f%u s%u rr%d\n", tp->rx_opt.sack_ok, inet_csk(sk)->icsk_ca_state, @@ -1456,18 +1460,22 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, if (!tcp_is_sackblock_valid(tp, dup_sack, sp[used_sacks].start_seq, sp[used_sacks].end_seq)) { + int mib_idx; + if (dup_sack) { if (!tp->undo_marker) - NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDNOUNDO); + mib_idx = LINUX_MIB_TCPDSACKIGNOREDNOUNDO; else - NET_INC_STATS_BH(LINUX_MIB_TCPDSACKIGNOREDOLD); + mib_idx = LINUX_MIB_TCPDSACKIGNOREDOLD; } else { /* Don't count olds caused by ACK reordering */ if ((TCP_SKB_CB(ack_skb)->ack_seq != tp->snd_una) && !after(sp[used_sacks].end_seq, tp->snd_una)) continue; - NET_INC_STATS_BH(LINUX_MIB_TCPSACKDISCARD); + mib_idx = LINUX_MIB_TCPSACKDISCARD; } + + NET_INC_STATS_BH(mib_idx); if (i == 0) first_sack_index = -1; continue; @@ -2380,15 +2388,19 @@ static int tcp_try_undo_recovery(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); if (tcp_may_undo(tp)) { + int mib_idx; + /* Happy end! We did not retransmit anything * or our original transmission succeeded. */ DBGUNDO(sk, inet_csk(sk)->icsk_ca_state == TCP_CA_Loss ? "loss" : "retrans"); tcp_undo_cwr(sk, 1); if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss) - NET_INC_STATS_BH(LINUX_MIB_TCPLOSSUNDO); + mib_idx = LINUX_MIB_TCPLOSSUNDO; else - NET_INC_STATS_BH(LINUX_MIB_TCPFULLUNDO); + mib_idx = LINUX_MIB_TCPFULLUNDO; + + NET_INC_STATS_BH(mib_idx); tp->undo_marker = 0; } if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) { @@ -2560,7 +2572,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag) int is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP)); int do_lost = is_dupack || ((flag & FLAG_DATA_SACKED) && (tcp_fackets_out(tp) > tp->reordering)); - int fast_rexmit = 0; + int fast_rexmit = 0, mib_idx; if (WARN_ON(!tp->packets_out && tp->sacked_out)) tp->sacked_out = 0; @@ -2683,9 +2695,11 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag) /* Otherwise enter Recovery state */ if (tcp_is_reno(tp)) - NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERY); + mib_idx = LINUX_MIB_TCPRENORECOVERY; else - NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERY); + mib_idx = LINUX_MIB_TCPSACKRECOVERY; + + NET_INC_STATS_BH(mib_idx); tp->high_seq = tp->snd_nxt; tp->prior_ssthresh = 0; @@ -3700,10 +3714,14 @@ static inline int tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, static void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq) { if (tcp_is_sack(tp) && sysctl_tcp_dsack) { + int mib_idx; + if (before(seq, tp->rcv_nxt)) - NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOLDSENT); + mib_idx = LINUX_MIB_TCPDSACKOLDSENT; else - NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFOSENT); + mib_idx = LINUX_MIB_TCPDSACKOFOSENT; + + NET_INC_STATS_BH(mib_idx); tp->rx_opt.dsack = 1; tp->duplicate_sack[0].start_seq = seq; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 8f83ab432705..edef2afe905e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1985,14 +1985,17 @@ void tcp_xmit_retransmit_queue(struct sock *sk) if (sacked & TCPCB_LOST) { if (!(sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))) { + int mib_idx; + if (tcp_retransmit_skb(sk, skb)) { tp->retransmit_skb_hint = NULL; return; } if (icsk->icsk_ca_state != TCP_CA_Loss) - NET_INC_STATS_BH(LINUX_MIB_TCPFASTRETRANS); + mib_idx = LINUX_MIB_TCPFASTRETRANS; else - NET_INC_STATS_BH(LINUX_MIB_TCPSLOWSTARTRETRANS); + mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS; + NET_INC_STATS_BH(mib_idx); if (skb == tcp_write_queue_head(sk)) inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 3e358cbb1247..6a480d1fd8f6 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -326,24 +326,27 @@ static void tcp_retransmit_timer(struct sock *sk) goto out; if (icsk->icsk_retransmits == 0) { + int mib_idx; + if (icsk->icsk_ca_state == TCP_CA_Disorder || icsk->icsk_ca_state == TCP_CA_Recovery) { if (tcp_is_sack(tp)) { if (icsk->icsk_ca_state == TCP_CA_Recovery) - NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERYFAIL); + mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL; else - NET_INC_STATS_BH(LINUX_MIB_TCPSACKFAILURES); + mib_idx = LINUX_MIB_TCPSACKFAILURES; } else { if (icsk->icsk_ca_state == TCP_CA_Recovery) - NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERYFAIL); + mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL; else - NET_INC_STATS_BH(LINUX_MIB_TCPRENOFAILURES); + mib_idx = LINUX_MIB_TCPRENOFAILURES; } } else if (icsk->icsk_ca_state == TCP_CA_Loss) { - NET_INC_STATS_BH(LINUX_MIB_TCPLOSSFAILURES); + mib_idx = LINUX_MIB_TCPLOSSFAILURES; } else { - NET_INC_STATS_BH(LINUX_MIB_TCPTIMEOUTS); + mib_idx = LINUX_MIB_TCPTIMEOUTS; } + NET_INC_STATS_BH(mib_idx); } if (tcp_use_frto(sk)) { -- 2.30.2