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

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

include/net/inetpeer.h

+26 −5
Original line number Original line Diff line number Diff line
@@ -22,12 +22,22 @@ 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;

	/*

	 * Once inet_peer is queued for deletion (refcnt == -1), following fields

	 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp

	 * We can share memory with rcu_head to keep inet_peer small

	 * (less then 64 bytes)

	 */

	union {

		struct {

			atomic_t	rid;		/* Frag reception counter */

			atomic_t	rid;		/* Frag reception counter */

			atomic_t	ip_id_count;	/* IP ID for the next packet */

			atomic_t	ip_id_count;	/* IP ID for the next packet */

			__u32		tcp_ts;

			__u32		tcp_ts;

			__u32		tcp_ts_stamp;

			__u32		tcp_ts_stamp;

		};

		struct rcu_head         rcu;

		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); 
/* 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;

}

}

net/ipv4/inetpeer.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -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) 




	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

net/ipv4/route.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -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;

net/ipv4/tcp_ipv4.c

+7 −4
Original line number Original line Diff line number Diff line
@@ -204,12 +204,14 @@ 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);

			if ((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_stamp = peer->tcp_ts_stamp;

				tp->rx_opt.ts_recent = peer->tcp_ts;

				tp->rx_opt.ts_recent = peer->tcp_ts;

			}

			}

		}

		}

	}





	inet->inet_dport = usin->sin_port;

	inet->inet_dport = usin->sin_port;

	inet->inet_daddr = daddr;

	inet->inet_daddr = daddr;
@@ -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) {