From 243bbcaa09e8482aa28065cbc2eb99f0ca2fc8d6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 6 Mar 2007 20:23:10 -0800 Subject: [PATCH] [IPV4]: Optimize inet_getpeer() 1) Some sysctl vars are declared __read_mostly 2) We can avoid updating stack[] when doing an AVL lookup only. lookup() macro is extended to receive a second parameter, that may be NULL in case of a pure lookup (no need to save the AVL path). This removes unnecessary instructions, because compiler knows if this _stack parameter is NULL or not. text size of net/ipv4/inetpeer.o is 2063 bytes instead of 2107 on x86_64 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/inetpeer.c | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-) diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index db3ef96bdfd9..2f44e6128068 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -87,10 +87,12 @@ static DEFINE_RWLOCK(peer_pool_lock); static int peer_total; /* Exported for sysctl_net_ipv4. */ -int inet_peer_threshold = 65536 + 128; /* start to throw entries more +int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries more * aggressively at this stage */ -int inet_peer_minttl = 120 * HZ; /* TTL under high load: 120 sec */ -int inet_peer_maxttl = 10 * 60 * HZ; /* usual time to live: 10 min */ +int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */ +int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */ +int inet_peer_gc_mintime __read_mostly = 10 * HZ; +int inet_peer_gc_maxtime __read_mostly = 120 * HZ; static struct inet_peer *inet_peer_unused_head; static struct inet_peer **inet_peer_unused_tailp = &inet_peer_unused_head; @@ -99,9 +101,6 @@ static DEFINE_SPINLOCK(inet_peer_unused_lock); static void peer_check_expire(unsigned long dummy); static DEFINE_TIMER(peer_periodic_timer, peer_check_expire, 0, 0); -/* Exported for sysctl_net_ipv4. */ -int inet_peer_gc_mintime = 10 * HZ, - inet_peer_gc_maxtime = 120 * HZ; /* Called from ip_output.c:ip_init */ void __init inet_initpeers(void) @@ -151,20 +150,27 @@ static void unlink_from_unused(struct inet_peer *p) spin_unlock_bh(&inet_peer_unused_lock); } -/* Called with local BH disabled and the pool lock held. */ -#define lookup(daddr) \ +/* + * Called with local BH disabled and the pool lock held. + * _stack is known to be NULL or not at compile time, + * so compiler will optimize the if (_stack) tests. + */ +#define lookup(_daddr,_stack) \ ({ \ struct inet_peer *u, **v; \ - stackptr = stack; \ - *stackptr++ = &peer_root; \ + if (_stack) { \ + stackptr = _stack; \ + *stackptr++ = &peer_root; \ + } \ for (u = peer_root; u != peer_avl_empty; ) { \ - if (daddr == u->v4daddr) \ + if (_daddr == u->v4daddr) \ break; \ - if ((__force __u32)daddr < (__force __u32)u->v4daddr) \ + if ((__force __u32)_daddr < (__force __u32)u->v4daddr) \ v = &u->avl_left; \ else \ v = &u->avl_right; \ - *stackptr++ = v; \ + if (_stack) \ + *stackptr++ = v; \ u = *v; \ } \ u; \ @@ -288,7 +294,7 @@ static void unlink_from_pool(struct inet_peer *p) if (atomic_read(&p->refcnt) == 1) { struct inet_peer **stack[PEER_MAXDEPTH]; struct inet_peer ***stackptr, ***delp; - if (lookup(p->v4daddr) != p) + if (lookup(p->v4daddr, stack) != p) BUG(); delp = stackptr - 1; /* *delp[0] == p */ if (p->avl_left == peer_avl_empty) { @@ -373,7 +379,7 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create) /* Look up for the address quickly. */ read_lock_bh(&peer_pool_lock); - p = lookup(daddr); + p = lookup(daddr, NULL); if (p != peer_avl_empty) atomic_inc(&p->refcnt); read_unlock_bh(&peer_pool_lock); @@ -400,7 +406,7 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create) write_lock_bh(&peer_pool_lock); /* Check if an entry has suddenly appeared. */ - p = lookup(daddr); + p = lookup(daddr, stack); if (p != peer_avl_empty) goto out_free; -- 2.30.2