From f86dcc5aa8c7908f2c287e7a211228df599e3e71 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 7 Oct 2009 00:37:59 +0000 Subject: udp: dynamically size hash tables at boot time UDP_HTABLE_SIZE was initialy defined to 128, which is a bit small for several setups. 4000 active UDP sockets -> 32 sockets per chain in average. An incoming frame has to lookup all sockets to find best match, so long chains hurt latency. Instead of a fixed size hash table that cant be perfect for every needs, let UDP stack choose its table size at boot time like tcp/ip route, using alloc_large_system_hash() helper Add an optional boot parameter, uhash_entries=x so that an admin can force a size between 256 and 65536 if needed, like thash_entries and rhash_entries. dmesg logs two new lines : [ 0.647039] UDP hash table entries: 512 (order: 0, 4096 bytes) [ 0.647099] UDP Lite hash table entries: 512 (order: 0, 4096 bytes) Maximal size on 64bit arches would be 65536 slots, ie 1 MBytes for non debugging spinlocks. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/udp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'net/ipv6/udp.c') diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index c6a303ec834..ff778c172ef 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -132,7 +132,7 @@ static struct sock *__udp6_lib_lookup(struct net *net, struct sock *sk, *result; struct hlist_nulls_node *node; unsigned short hnum = ntohs(dport); - unsigned int hash = udp_hashfn(net, hnum); + unsigned int hash = udp_hashfn(net, hnum, udptable->mask); struct udp_hslot *hslot = &udptable->hash[hash]; int score, badness; @@ -452,7 +452,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, { struct sock *sk, *sk2; const struct udphdr *uh = udp_hdr(skb); - struct udp_hslot *hslot = &udptable->hash[udp_hashfn(net, ntohs(uh->dest))]; + struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest)); int dif; spin_lock(&hslot->lock); @@ -1197,7 +1197,7 @@ static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket destp = ntohs(inet->dport); srcp = ntohs(inet->sport); seq_printf(seq, - "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " + "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X " "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d\n", bucket, src->s6_addr32[0], src->s6_addr32[1], -- cgit v1.2.3