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Message-ID: <485931B5.2020509@openvz.org>
Date: Wed, 18 Jun 2008 20:03:01 +0400
From: Pavel Emelyanov <xemul@...nvz.org>
To: David Miller <davem@...emloft.net>
CC: Linux Netdev List <netdev@...r.kernel.org>
Subject: [PATCH net-next-2.6] 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 (<something>)
NET_INC_STATS_BH(<some_id>);
else if (<something_else>)
NET_INC_STATS_BH(<some_other_id>);
...
else
NET_INC_STATS_BH(<default_id>);
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 <xemul@...nvz.org>
---
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index de30e70..d6ea970 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 8f83ab4..edef2af 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 3e358cb..6a480d1 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)) {
--
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