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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-10-07 02:37:59 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-10-08 07:00:22 +0200 |
| commit | f86dcc5aa8c7908f2c287e7a211228df599e3e71 (patch) | |
| tree | 1721c94d0254b337b0668b2e331771dfef4b142d /include | |
| parent | IPv6: Fix 6RD typo (diff) | |
| download | linux-f86dcc5aa8c7908f2c287e7a211228df599e3e71.tar.xz linux-f86dcc5aa8c7908f2c287e7a211228df599e3e71.zip | |
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')
| -rw-r--r-- | include/linux/udp.h | 6 | ||||
| -rw-r--r-- | include/net/udp.h | 13 |
2 files changed, 13 insertions, 6 deletions
diff --git a/include/linux/udp.h b/include/linux/udp.h index 0cf5c4c0ec81..832361e3e596 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 { diff --git a/include/net/udp.h b/include/net/udp.h index f98abd2ce709..22aa2e7eb1d7 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -54,12 +54,19 @@ struct udp_hslot { struct hlist_nulls_head head; spinlock_t lock; } __attribute__((aligned(2 * sizeof(long)))); + struct udp_table { - struct udp_hslot hash[UDP_HTABLE_SIZE]; + struct udp_hslot *hash; + unsigned int mask; + unsigned int log; }; extern struct udp_table udp_table; -extern void udp_table_init(struct udp_table *); - +extern void udp_table_init(struct udp_table *, const char *); +static inline struct udp_hslot *udp_hashslot(struct udp_table *table, + struct net *net, unsigned num) +{ + return &table->hash[udp_hashfn(net, num, table->mask)]; +} /* Note: this must match 'valbool' in sock_setsockopt */ #define UDP_CSUM_NOXMIT 1 |