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inetpeer: Optimize inet_getid()

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While investigating for network latencies, I found inet_getid() was a
contention point for some workloads, as inet_peer_idlock is shared
by all inet_getid() users regardless of peers.

One way to fix this is to make ip_id_count an atomic_t instead
of __u16, and use atomic_add_return().

In order to keep sizeof(struct inet_peer) = 64 on 64bit arches
tcp_ts_stamp is also converted to __u32 instead of "unsigned long".

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2009-11-12 09:33:09 +00:00 committed by David S. Miller
parent 234b27c3fd
commit 2c1409a0a2
4 changed files with 15 additions and 24 deletions
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16
include/net/inetpeer.h
View file

@ -17,15 +17,15 @@ struct inet_peer {
/* group together avl_left,avl_right,v4daddr to speedup lookups */
struct inet_peer *avl_left, *avl_right;
__be32 v4daddr; /* peer's address */
__u16 avl_height;
__u16 ip_id_count; /* IP ID for the next packet */
__u32 avl_height;
struct list_head unused;
__u32 dtime; /* the time of last use of not
* referenced entries */
atomic_t refcnt;
atomic_t rid; /* Frag reception counter */
atomic_t ip_id_count; /* IP ID for the next packet */
__u32 tcp_ts;
unsigned long tcp_ts_stamp;
__u32 tcp_ts_stamp;
};
void inet_initpeers(void) __init;
@ -36,17 +36,11 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create);
/* can be called from BH context or outside */
extern void inet_putpeer(struct inet_peer *p);
extern spinlock_t inet_peer_idlock;
/* can be called with or without local BH being disabled */
static inline __u16 inet_getid(struct inet_peer *p, int more)
{
__u16 id;
spin_lock_bh(&inet_peer_idlock);
id = p->ip_id_count;
p->ip_id_count += 1 + more;
spin_unlock_bh(&inet_peer_idlock);
return id;
more++;
return atomic_add_return(more, &p->ip_id_count) - more;
}
#endif /* _NET_INETPEER_H */

5
net/ipv4/inetpeer.c
View file

@ -67,9 +67,6 @@
* ip_id_count: idlock
*/
/* Exported for inet_getid inline function. */
DEFINE_SPINLOCK(inet_peer_idlock);
static struct kmem_cache *peer_cachep __read_mostly;
#define node_height(x) x->avl_height
@ -390,7 +387,7 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create)
n->v4daddr = daddr;
atomic_set(&n->refcnt, 1);
atomic_set(&n->rid, 0);
n->ip_id_count = secure_ip_id(daddr);
atomic_set(&n->ip_id_count, secure_ip_id(daddr));
n->tcp_ts_stamp = 0;
write_lock_bh(&peer_pool_lock);

2
net/ipv4/route.c
View file

@ -2852,7 +2852,7 @@ static int rt_fill_info(struct net *net,
error = rt->u.dst.error;
expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
if (rt->peer) {
id = rt->peer->ip_id_count;
id = atomic_read(&rt->peer->ip_id_count) & 0xffff;
if (rt->peer->tcp_ts_stamp) {
ts = rt->peer->tcp_ts;
tsage = get_seconds() - rt->peer->tcp_ts_stamp;

16
net/ipv4/tcp_ipv4.c
View file

@ -204,7 +204,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
* when trying new connection.
*/
if (peer != NULL &&
peer->tcp_ts_stamp + TCP_PAWS_MSL >= get_seconds()) {
(u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
tp->rx_opt.ts_recent = peer->tcp_ts;
}
@ -1308,7 +1308,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
tcp_death_row.sysctl_tw_recycle &&
(peer = rt_get_peer((struct rtable *)dst)) != NULL &&
peer->v4daddr == saddr) {
if (get_seconds() < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
(s32)(peer->tcp_ts - req->ts_recent) >
TCP_PAWS_WINDOW) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
@ -1727,9 +1727,9 @@ int tcp_v4_remember_stamp(struct sock *sk)
if (peer) {
if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
(peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
((u32)get_seconds() - peer->tcp_ts_stamp > TCP_PAWS_MSL &&
peer->tcp_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
peer->tcp_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
peer->tcp_ts = tp->rx_opt.ts_recent;
}
if (release_it)
@ -1748,9 +1748,9 @@ int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
(peer->tcp_ts_stamp + TCP_PAWS_MSL < get_seconds() &&
peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
((u32)get_seconds() - peer->tcp_ts_stamp > TCP_PAWS_MSL &&
peer->tcp_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
peer->tcp_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
peer->tcp_ts = tcptw->tw_ts_recent;
}
inet_putpeer(peer);