From 3ab5aee7fe840b5b1b35a8d1ac11c3de5281e611 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 16 Nov 2008 19:40:17 -0800 Subject: net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls RCU was added to UDP lookups, using a fast infrastructure : - sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the price of call_rcu() at freeing time. - hlist_nulls permits to use few memory barriers. This patch uses same infrastructure for TCP/DCCP established and timewait sockets. Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications using short lived TCP connections. A followup patch, converting rwlocks to spinlocks will even speedup this case. __inet_lookup_established() is pretty fast now we dont have to dirty a contended cache line (read_lock/read_unlock) Only established and timewait hashtable are converted to RCU (bind table and listen table are still using traditional locking) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp.c') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index f60a5917e54..044224a341e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2707,8 +2707,8 @@ void __init tcp_init(void) thash_entries ? 0 : 512 * 1024); tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; for (i = 0; i < tcp_hashinfo.ehash_size; i++) { - INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain); - INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain); + INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i); + INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i); } if (inet_ehash_locks_alloc(&tcp_hashinfo)) panic("TCP: failed to alloc ehash_locks"); -- cgit v1.2.3