Commit 317fe0e6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

inetpeer: restore small inet_peer structures

Addition of rcu_head to struct inet_peer added 16bytes on 64bit arches.

Thats a bit unfortunate, since old size was exactly 64 bytes.

This can be solved, using an union between this rcu_head an four fields,
that are normally used only when a refcount is taken on inet_peer.
rcu_head is used only when refcnt=-1, right before structure freeing.

Add a inet_peer_refcheck() function to check this assertion for a while.

We can bring back SLAB_HWCACHE_ALIGN qualifier in kmem cache creation.
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fdb93f8a
...@@ -22,11 +22,21 @@ struct inet_peer { ...@@ -22,11 +22,21 @@ struct inet_peer {
__u32 dtime; /* the time of last use of not __u32 dtime; /* the time of last use of not
* referenced entries */ * referenced entries */
atomic_t refcnt; atomic_t refcnt;
atomic_t rid; /* Frag reception counter */ /*
atomic_t ip_id_count; /* IP ID for the next packet */ * Once inet_peer is queued for deletion (refcnt == -1), following fields
__u32 tcp_ts; * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
__u32 tcp_ts_stamp; * We can share memory with rcu_head to keep inet_peer small
struct rcu_head rcu; * (less then 64 bytes)
*/
union {
struct {
atomic_t rid; /* Frag reception counter */
atomic_t ip_id_count; /* IP ID for the next packet */
__u32 tcp_ts;
__u32 tcp_ts_stamp;
};
struct rcu_head rcu;
};
}; };
void inet_initpeers(void) __init; void inet_initpeers(void) __init;
...@@ -37,10 +47,21 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create); ...@@ -37,10 +47,21 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create);
/* can be called from BH context or outside */ /* can be called from BH context or outside */
extern void inet_putpeer(struct inet_peer *p); extern void inet_putpeer(struct inet_peer *p);
/*
* temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
* tcp_ts_stamp if no refcount is taken on inet_peer
*/
static inline void inet_peer_refcheck(const struct inet_peer *p)
{
WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
}
/* can be called with or without local BH being disabled */ /* can be called with or without local BH being disabled */
static inline __u16 inet_getid(struct inet_peer *p, int more) static inline __u16 inet_getid(struct inet_peer *p, int more)
{ {
more++; more++;
inet_peer_refcheck(p);
return atomic_add_return(more, &p->ip_id_count) - more; return atomic_add_return(more, &p->ip_id_count) - more;
} }
......
...@@ -64,7 +64,7 @@ ...@@ -64,7 +64,7 @@
* usually under some other lock to prevent node disappearing * usually under some other lock to prevent node disappearing
* dtime: unused node list lock * dtime: unused node list lock
* v4daddr: unchangeable * v4daddr: unchangeable
* ip_id_count: idlock * ip_id_count: atomic value (no lock needed)
*/ */
static struct kmem_cache *peer_cachep __read_mostly; static struct kmem_cache *peer_cachep __read_mostly;
...@@ -129,7 +129,7 @@ void __init inet_initpeers(void) ...@@ -129,7 +129,7 @@ void __init inet_initpeers(void)
peer_cachep = kmem_cache_create("inet_peer_cache", peer_cachep = kmem_cache_create("inet_peer_cache",
sizeof(struct inet_peer), sizeof(struct inet_peer),
0, SLAB_PANIC, 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC,
NULL); NULL);
/* All the timers, started at system startup tend /* All the timers, started at system startup tend
......
...@@ -2881,6 +2881,7 @@ static int rt_fill_info(struct net *net, ...@@ -2881,6 +2881,7 @@ static int rt_fill_info(struct net *net,
error = rt->dst.error; error = rt->dst.error;
expires = rt->dst.expires ? rt->dst.expires - jiffies : 0; expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
if (rt->peer) { if (rt->peer) {
inet_peer_refcheck(rt->peer);
id = atomic_read(&rt->peer->ip_id_count) & 0xffff; id = atomic_read(&rt->peer->ip_id_count) & 0xffff;
if (rt->peer->tcp_ts_stamp) { if (rt->peer->tcp_ts_stamp) {
ts = rt->peer->tcp_ts; ts = rt->peer->tcp_ts;
......
...@@ -204,10 +204,12 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) ...@@ -204,10 +204,12 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
* TIME-WAIT * and initialize rx_opt.ts_recent from it, * TIME-WAIT * and initialize rx_opt.ts_recent from it,
* when trying new connection. * when trying new connection.
*/ */
if (peer != NULL && if (peer) {
(u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) { inet_peer_refcheck(peer);
tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
tp->rx_opt.ts_recent = peer->tcp_ts; tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
tp->rx_opt.ts_recent = peer->tcp_ts;
}
} }
} }
...@@ -1351,6 +1353,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) ...@@ -1351,6 +1353,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
(dst = inet_csk_route_req(sk, req)) != NULL && (dst = inet_csk_route_req(sk, req)) != NULL &&
(peer = rt_get_peer((struct rtable *)dst)) != NULL && (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
peer->v4daddr == saddr) { peer->v4daddr == saddr) {
inet_peer_refcheck(peer);
if ((u32)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) > (s32)(peer->tcp_ts - req->ts_recent) >
TCP_PAWS_WINDOW) { TCP_PAWS_WINDOW) {
......
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