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Date: Tue, 22 Apr 2008 18:35:42 +0400
From: Pavel Emelyanov <xemul@...nvz.org>
To: YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
CC: netdev@...r.kernel.org
Subject: Re: [RFC PATCH net-2.6.26 (Plan B)] [TCP]: Lower stack usage in tcp4_seq_show().
YOSHIFUJI Hideaki wrote:
> tcp4_seq_show() eats about 250 bytes. By using buffer in seq_file
> directly, it will be reduced around 100 bytes.
>
> One drawback is higher usage of slab for IPv6 but the format
> will not change with this patch.
>
> Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
Plan C: we can follow the Al Viro's proposal about %n like in this patch.
The same applies to udp, fib (the /proc/net/route file), rt_cache and
sctp debug. This is minus ~150-200 bytes for each.
How do you think?
Signed-off-by: Pavel Emelyanov <xemul@...nvz.org>
diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c
index 02088de..2e2fc33 100644
--- a/net/ipv4/fib_hash.c
+++ b/net/ipv4/fib_hash.c
@@ -1003,7 +1003,7 @@ static unsigned fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
static int fib_seq_show(struct seq_file *seq, void *v)
{
struct fib_iter_state *iter;
- char bf[128];
+ int len;
__be32 prefix, mask;
unsigned flags;
struct fib_node *f;
@@ -1025,18 +1025,19 @@ static int fib_seq_show(struct seq_file *seq, void *v)
mask = FZ_MASK(iter->zone);
flags = fib_flag_trans(fa->fa_type, mask, fi);
if (fi)
- snprintf(bf, sizeof(bf),
- "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
+ seq_printf(seq,
+ "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u%n",
fi->fib_dev ? fi->fib_dev->name : "*", prefix,
fi->fib_nh->nh_gw, flags, 0, 0, fi->fib_priority,
mask, (fi->fib_advmss ? fi->fib_advmss + 40 : 0),
fi->fib_window,
- fi->fib_rtt >> 3);
+ fi->fib_rtt >> 3, &len);
else
- snprintf(bf, sizeof(bf),
- "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
- prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0);
- seq_printf(seq, "%-127s\n", bf);
+ seq_printf(seq,
+ "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u%n",
+ prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0, &len);
+
+ seq_printf(seq, "%*s\n", 127 - len, "");
out:
return 0;
}
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index ea294ff..4b02d14 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2602,15 +2602,16 @@ static int fib_route_seq_show(struct seq_file *seq, void *v)
list_for_each_entry_rcu(fa, &li->falh, fa_list) {
const struct fib_info *fi = fa->fa_info;
unsigned flags = fib_flag_trans(fa->fa_type, mask, fi);
- char bf[128];
+ int len;
if (fa->fa_type == RTN_BROADCAST
|| fa->fa_type == RTN_MULTICAST)
continue;
if (fi)
- snprintf(bf, sizeof(bf),
- "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
+ seq_printf(seq,
+ "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
+ "%d\t%08X\t%d\t%u\t%u%n",
fi->fib_dev ? fi->fib_dev->name : "*",
prefix,
fi->fib_nh->nh_gw, flags, 0, 0,
@@ -2619,14 +2620,15 @@ static int fib_route_seq_show(struct seq_file *seq, void *v)
(fi->fib_advmss ?
fi->fib_advmss + 40 : 0),
fi->fib_window,
- fi->fib_rtt >> 3);
+ fi->fib_rtt >> 3, &len);
else
- snprintf(bf, sizeof(bf),
- "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
+ seq_printf(seq,
+ "*\t%08X\t%08X\t%04X\t%d\t%u\t"
+ "%d\t%08X\t%d\t%u\t%u%n",
prefix, 0, flags, 0, 0, 0,
- mask, 0, 0, 0);
+ mask, 0, 0, 0, &len);
- seq_printf(seq, "%-127s\n", bf);
+ seq_printf(seq, "%*s\n", 127 - len, "");
}
}
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 780e948..ce25a13 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -367,10 +367,10 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
"HHUptod\tSpecDst");
else {
struct rtable *r = v;
- char temp[256];
+ int len;
- sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
- "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X",
+ seq_printf(seq, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
+ "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
r->u.dst.dev ? r->u.dst.dev->name : "*",
(unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
r->rt_flags, atomic_read(&r->u.dst.__refcnt),
@@ -384,8 +384,9 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
r->u.dst.hh ? (r->u.dst.hh->hh_output ==
dev_queue_xmit) : 0,
- r->rt_spec_dst);
- seq_printf(seq, "%-127s\n", temp);
+ r->rt_spec_dst, &len);
+
+ seq_printf(seq, "%*s\n", 127 - len, "");
}
return 0;
}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 7766151..0e9bc12 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2255,13 +2255,13 @@ void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
}
static void get_openreq4(struct sock *sk, struct request_sock *req,
- char *tmpbuf, int i, int uid)
+ struct seq_file *f, int i, int uid, int *len)
{
const struct inet_request_sock *ireq = inet_rsk(req);
int ttd = req->expires - jiffies;
- sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
+ seq_printf(f, "%4d: %08X:%04X %08X:%04X"
+ " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
i,
ireq->loc_addr,
ntohs(inet_sk(sk)->sport),
@@ -2276,10 +2276,11 @@ static void get_openreq4(struct sock *sk, struct request_sock *req,
0, /* non standard timer */
0, /* open_requests have no inode */
atomic_read(&sk->sk_refcnt),
- req);
+ req,
+ len);
}
-static void get_tcp4_sock(struct sock *sk, char *tmpbuf, int i)
+static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
{
int timer_active;
unsigned long timer_expires;
@@ -2305,8 +2306,8 @@ static void get_tcp4_sock(struct sock *sk, char *tmpbuf, int i)
timer_expires = jiffies;
}
- sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
- "%08X %5d %8d %lu %d %p %u %u %u %u %d",
+ seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
+ "%08X %5d %8d %lu %d %p %u %u %u %u %d%n",
i, src, srcp, dest, destp, sk->sk_state,
tp->write_seq - tp->snd_una,
sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
@@ -2322,11 +2323,12 @@ static void get_tcp4_sock(struct sock *sk, char *tmpbuf, int i)
icsk->icsk_ack.ato,
(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
tp->snd_cwnd,
- tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
+ tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
+ len);
}
static void get_timewait4_sock(struct inet_timewait_sock *tw,
- char *tmpbuf, int i)
+ struct seq_file *f, int i, int *len)
{
__be32 dest, src;
__u16 destp, srcp;
@@ -2340,11 +2342,11 @@ static void get_timewait4_sock(struct inet_timewait_sock *tw,
destp = ntohs(tw->tw_dport);
srcp = ntohs(tw->tw_sport);
- sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
+ seq_printf(f, "%4d: %08X:%04X %08X:%04X"
+ " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
- atomic_read(&tw->tw_refcnt), tw);
+ atomic_read(&tw->tw_refcnt), tw, len);
}
#define TMPSZ 150
@@ -2352,7 +2354,7 @@ static void get_timewait4_sock(struct inet_timewait_sock *tw,
static int tcp4_seq_show(struct seq_file *seq, void *v)
{
struct tcp_iter_state* st;
- char tmpbuf[TMPSZ + 1];
+ int len;
if (v == SEQ_START_TOKEN) {
seq_printf(seq, "%-*s\n", TMPSZ - 1,
@@ -2366,16 +2368,16 @@ static int tcp4_seq_show(struct seq_file *seq, void *v)
switch (st->state) {
case TCP_SEQ_STATE_LISTENING:
case TCP_SEQ_STATE_ESTABLISHED:
- get_tcp4_sock(v, tmpbuf, st->num);
+ get_tcp4_sock(v, seq, st->num, &len);
break;
case TCP_SEQ_STATE_OPENREQ:
- get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
+ get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
break;
case TCP_SEQ_STATE_TIME_WAIT:
- get_timewait4_sock(v, tmpbuf, st->num);
+ get_timewait4_sock(v, seq, st->num, &len);
break;
}
- seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
+ seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
out:
return 0;
}
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b053ac7..1f535e3 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1619,7 +1619,8 @@ void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
}
/* ------------------------------------------------------------------------ */
-static void udp4_format_sock(struct sock *sp, char *tmpbuf, int bucket)
+static void udp4_format_sock(struct sock *sp, struct seq_file *f,
+ int bucket, int *len)
{
struct inet_sock *inet = inet_sk(sp);
__be32 dest = inet->daddr;
@@ -1627,13 +1628,13 @@ static void udp4_format_sock(struct sock *sp, char *tmpbuf, int bucket)
__u16 destp = ntohs(inet->dport);
__u16 srcp = ntohs(inet->sport);
- sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p",
+ seq_printf(f, "%4d: %08X:%04X %08X:%04X"
+ " %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p%n",
bucket, src, srcp, dest, destp, sp->sk_state,
atomic_read(&sp->sk_wmem_alloc),
atomic_read(&sp->sk_rmem_alloc),
0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
- atomic_read(&sp->sk_refcnt), sp);
+ atomic_read(&sp->sk_refcnt), sp, len);
}
int udp4_seq_show(struct seq_file *seq, void *v)
@@ -1644,11 +1645,11 @@ int udp4_seq_show(struct seq_file *seq, void *v)
"rx_queue tr tm->when retrnsmt uid timeout "
"inode");
else {
- char tmpbuf[129];
struct udp_iter_state *state = seq->private;
+ int len;
- udp4_format_sock(v, tmpbuf, state->bucket);
- seq_printf(seq, "%-127s\n", tmpbuf);
+ udp4_format_sock(v, seq, state->bucket, &len);
+ seq_printf(seq, "%*s\n", 127 - len ,"");
}
return 0;
}
diff --git a/net/sctp/objcnt.c b/net/sctp/objcnt.c
index cfeb07e..f73ec0e 100644
--- a/net/sctp/objcnt.c
+++ b/net/sctp/objcnt.c
@@ -83,13 +83,12 @@ static sctp_dbg_objcnt_entry_t sctp_dbg_objcnt[] = {
*/
static int sctp_objcnt_seq_show(struct seq_file *seq, void *v)
{
- int i;
- char temp[128];
+ int i, len;
i = (int)*(loff_t *)v;
- sprintf(temp, "%s: %d", sctp_dbg_objcnt[i].label,
- atomic_read(sctp_dbg_objcnt[i].counter));
- seq_printf(seq, "%-127s\n", temp);
+ seq_printf(seq, "%s: %d%n", sctp_dbg_objcnt[i].label,
+ atomic_read(sctp_dbg_objcnt[i].counter), &len);
+ seq_printf(seq, "%*s\n", 127 - len, "");
return 0;
}
--
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