Commit fd90b29d authored Nov 30, 2012 by Eric Dumazet Committed by David S. Miller Dec 01, 2012

tcp: change default tcp hash size



As time passed, available memory increased faster than number of
concurrent tcp sockets.

As a result, a machine with 4GB of ram gets a hash table
with 524288 slots, using 8388608 bytes of memory.

Lets change that by a 16x factor (one slot for 128 KB of ram)

Even if a small machine needs a _lot_ of sockets, tcp lookups are now
very efficient, using one cache line per socket.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent abe303db

net/ipv4/tcp.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -3590,8 +3590,7 @@ void __init tcp_init(void)
		alloc_large_system_hash("TCP established",
		sizeof(struct inet_ehash_bucket),
		thash_entries,
		(totalram_pages >= 128 * 1024) ?
		13 : 15,
		17, /* one slot per 128 KB of memory */
		0,
		NULL,
		&tcp_hashinfo.ehash_mask,
		@@ -3607,8 +3606,7 @@ void __init tcp_init(void)
		alloc_large_system_hash("TCP bind",
		sizeof(struct inet_bind_hashbucket),
		tcp_hashinfo.ehash_mask + 1,
		(totalram_pages >= 128 * 1024) ?
		13 : 15,
		17, /* one slot per 128 KB of memory */
		0,
		&tcp_hashinfo.bhash_size,
		NULL,

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