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authorEric Dumazet <eric.dumazet@gmail.com>2009-10-07 00:37:59 +0000
committerDavid S. Miller <davem@davemloft.net>2009-10-07 22:00:22 -0700
commitf86dcc5aa8c7908f2c287e7a211228df599e3e71 (patch)
tree1721c94d0254b337b0668b2e331771dfef4b142d /include/linux
parent8a6dfd43d1891882f8ca05d73aa7735fb0edae3b (diff)
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 <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/udp.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 0cf5c4c0ec8..832361e3e59 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -45,11 +45,11 @@ static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
return (struct udphdr *)skb_transport_header(skb);
}
-#define UDP_HTABLE_SIZE 128
+#define UDP_HTABLE_SIZE_MIN (CONFIG_BASE_SMALL ? 128 : 256)
-static inline int udp_hashfn(struct net *net, const unsigned num)
+static inline int udp_hashfn(struct net *net, unsigned num, unsigned mask)
{
- return (num + net_hash_mix(net)) & (UDP_HTABLE_SIZE - 1);
+ return (num + net_hash_mix(net)) & mask;
}
struct udp_sock {