From 64b5c251d5b2cee4a0f697bfb90d79263f6dd517 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 2 Jun 2014 05:26:03 -0700 Subject: inetpeer: get rid of ip_id_count [ Upstream commit 73f156a6e8c1074ac6327e0abd1169e95eb66463 ] Ideally, we would need to generate IP ID using a per destination IP generator. linux kernels used inet_peer cache for this purpose, but this had a huge cost on servers disabling MTU discovery. 1) each inet_peer struct consumes 192 bytes 2) inetpeer cache uses a binary tree of inet_peer structs, with a nominal size of ~66000 elements under load. 3) lookups in this tree are hitting a lot of cache lines, as tree depth is about 20. 4) If server deals with many tcp flows, we have a high probability of not finding the inet_peer, allocating a fresh one, inserting it in the tree with same initial ip_id_count, (cf secure_ip_id()) 5) We garbage collect inet_peer aggressively. IP ID generation do not have to be 'perfect' Goal is trying to avoid duplicates in a short period of time, so that reassembly units have a chance to complete reassembly of fragments belonging to one message before receiving other fragments with a recycled ID. We simply use an array of generators, and a Jenkin hash using the dst IP as a key. ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it belongs (it is only used from this file) secure_ip_id() and secure_ipv6_id() no longer are needed. Rename ip_select_ident_more() to ip_select_ident_segs() to avoid unnecessary decrement/increment of the number of segments. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- include/net/ipip.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net/ipip.h') diff --git a/include/net/ipip.h b/include/net/ipip.h index 4dccfe3..e8ee3bb 100644 --- a/include/net/ipip.h +++ b/include/net/ipip.h @@ -50,7 +50,7 @@ struct ip_tunnel_prl_entry { int pkt_len = skb->len - skb_transport_offset(skb); \ \ skb->ip_summed = CHECKSUM_NONE; \ - ip_select_ident(skb, &rt->dst, NULL); \ + ip_select_ident(skb, NULL); \ \ err = ip_local_out(skb); \ if (likely(net_xmit_eval(err) == 0)) { \ -- cgit v1.1