user/sven/linux.git/include/net/inet_sock.h, branch v3.10.65

ipv6: use a stronger hash for tcp

2013-02-21T23:15:58Z

It looks like its possible to open thousands of TCP IPv6 sessions on a server, all landing in a single slot of TCP hash table. Incoming packets have to lookup sockets in a very long list. We should hash all bits from foreign IPv6 addresses, using a salt and hash mix, not a simple XOR. inet6_ehashfn() can also separately use the ports, instead of xoring them. Reported-by: Neal Cardwell Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Signed-off-by: David S. Miller

net: move inet_dport/inet_num in sock_common

2012-11-30T20:02:56Z

commit 68835aba4d9b (net: optimize INET input path further) moved some fields used for tcp/udp sockets lookup in the first cache line of struct sock_common. This patch moves inet_dport/inet_num as well, filling a 32bit hole on 64 bit arches and reducing number of cache line misses in lookups. Also change INET_MATCH()/INET_TW_MATCH() to perform the ports match before addresses match, as this check is more discriminant. Remove the hash check from MATCH() macros because we dont need to re validate the hash value after taking a refcount on socket, and use likely/unlikely compiler hints, as the sk_hash/hash check makes the following conditional tests 100% predicted by cpu. Introduce skc_addrpair/skc_portpair pair values to better document the alignment requirements of the port/addr pairs used in the various MATCH() macros, and remove some casts. The namespace check can also be done at last. This slightly improves TCP/UDP lookup times. IP/TCP early demux needs inet->rx_dst_ifindex and TCP needs inet->min_ttl, lets group them together in same cache line. With help from Ben Hutchings & Joe Perches. Idea of this patch came after Ling Ma proposal to move skc_hash to the beginning of struct sock_common, and should allow him to submit a final version of his patch. My tests show an improvement doing so. Signed-off-by: Eric Dumazet Cc: Ben Hutchings Cc: Joe Perches Cc: Ling Ma Signed-off-by: David S. Miller

net: use a per task frag allocator

2012-09-24T20:31:37Z

We currently use a per socket order-0 page cache for tcp_sendmsg() operations. This page is used to build fragments for skbs. Its done to increase probability of coalescing small write() into single segments in skbs still in write queue (not yet sent) But it wastes a lot of memory for applications handling many mostly idle sockets, since each socket holds one page in sk->sk_sndmsg_page Its also quite inefficient to build TSO 64KB packets, because we need about 16 pages per skb on arches where PAGE_SIZE = 4096, so we hit page allocator more than wanted. This patch adds a per task frag allocator and uses bigger pages, if available. An automatic fallback is done in case of memory pressure. (up to 32768 bytes per frag, thats order-3 pages on x86) This increases TCP stream performance by 20% on loopback device, but also benefits on other network devices, since 8x less frags are mapped on transmit and unmapped on tx completion. Alexander Duyck mentioned a probable performance win on systems with IOMMU enabled. Its possible some SG enabled hardware cant cope with bigger fragments, but their ndo_start_xmit() should already handle this, splitting a fragment in sub fragments, since some arches have PAGE_SIZE=65536 Successfully tested on various ethernet devices. (ixgbe, igb, bnx2x, tg3, mellanox mlx4) Signed-off-by: Eric Dumazet Cc: Ben Hutchings Cc: Vijay Subramanian Cc: Alexander Duyck Tested-by: Vijay Subramanian Signed-off-by: David S. Miller

net: ipv6: fix TCP early demux

2012-08-06T20:33:21Z

IPv6 needs a cookie in dst_check() call. We need to add rx_dst_cookie and provide a family independent sk_rx_dst_set(sk, skb) method to properly support IPv6 TCP early demux. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ipv4: Restore old dst_free() behavior.

2012-07-31T21:41:38Z

commit 404e0a8b6a55 (net: ipv4: fix RCU races on dst refcounts) tried to solve a race but added a problem at device/fib dismantle time : We really want to call dst_free() as soon as possible, even if sockets still have dst in their cache. dst_release() calls in free_fib_info_rcu() are not welcomed. Root of the problem was that now we also cache output routes (in nh_rth_output), we must use call_rcu() instead of call_rcu_bh() in rt_free(), because output route lookups are done in process context. Based on feedback and initial patch from David Miller (adding another call_rcu_bh() call in fib, but it appears it was not the right fix) I left the inet_sk_rx_dst_set() helper and added __rcu attributes to nh_rth_output and nh_rth_input to better document what is going on in this code. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: ipv4: fix RCU races on dst refcounts

2012-07-30T21:53:22Z

commit c6cffba4ffa2 (ipv4: Fix input route performance regression.) added various fatal races with dst refcounts. crashes happen on tcp workloads if routes are added/deleted at the same time. The dst_free() calls from free_fib_info_rcu() are clearly racy. We need instead regular dst refcounting (dst_release()) and make sure dst_release() is aware of RCU grace periods : Add DST_RCU_FREE flag so that dst_release() respects an RCU grace period before dst destruction for cached dst Introduce a new inet_sk_rx_dst_set() helper, using atomic_inc_not_zero() to make sure we dont increase a zero refcount (On a dst currently waiting an rcu grace period before destruction) rt_cache_route() must take a reference on the new cached route, and release it if was not able to install it. With this patch, my machines survive various benchmarks. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ipv4: Prepare for change of rt->rt_iif encoding.

2012-07-23T23:36:26Z

Use inet_iif() consistently, and for TCP record the input interface of cached RX dst in inet sock. rt->rt_iif is going to be encoded differently, so that we can legitimately cache input routes in the FIB info more aggressively. When the input interface is "use SKB device index" the rt->rt_iif will be set to zero. This forces us to move the TCP RX dst cache installation into the ipv4 specific code, and as well it should since doing the route caching for ipv6 is pointless at the moment since it is not inspected in the ipv6 input paths yet. Also, remove the unlikely on dst->obsolete, all ipv4 dsts have obsolete set to a non-zero value to force invocation of the check callback. Signed-off-by: David S. Miller

inet: Kill FLOWI_FLAG_PRECOW_METRICS.

2012-07-11T05:40:12Z

No longer needed. TCP writes metrics, but now in it's own special cache that does not dirty the route metrics. Therefore there is no longer any reason to pre-cow metrics in this way. Signed-off-by: David S. Miller

net: implement IP_RECVTOS for IP_PKTOPTIONS

2012-02-13T05:46:41Z

Currently, it is not easily possible to get TOS/DSCP value of packets from an incoming TCP stream. The mechanism is there, IP_PKTOPTIONS getsockopt with IP_RECVTOS set, the same way as incoming TTL can be queried. This is not actually implemented for TOS, though. This patch adds this functionality, both for IPv4 (IP_PKTOPTIONS) and IPv6 (IPV6_2292PKTOPTIONS). For IPv4, like in the IP_RECVTTL case, the value of the TOS field is stored from the other party's ACK. This is needed for proxies which require DSCP transparency. One such example is at http://zph.bratcheda.org/. Signed-off-by: Jiri Benc Signed-off-by: David S. Miller

ipv4: Implement IP_UNICAST_IF socket option.

2012-02-08T20:52:45Z

The IP_UNICAST_IF feature is needed by the Wine project. This patch implements the feature by setting the outgoing interface in a similar fashion to that of IP_MULTICAST_IF. A separate option is needed to handle this feature since the existing options do not provide all of the characteristics required by IP_UNICAST_IF, a summary is provided below. SO_BINDTODEVICE: * SO_BINDTODEVICE requires administrative privileges, IP_UNICAST_IF does not. From reading some old mailing list articles my understanding is that SO_BINDTODEVICE requires administrative privileges because it can override the administrator's routing settings. * The SO_BINDTODEVICE option restricts both outbound and inbound traffic, IP_UNICAST_IF only impacts outbound traffic. IP_PKTINFO: * Since IP_PKTINFO and IP_UNICAST_IF are independent options, implementing IP_UNICAST_IF with IP_PKTINFO will likely break some applications. * Implementing IP_UNICAST_IF on top of IP_PKTINFO significantly complicates the Wine codebase and reduces the socket performance (doing this requires a lot of extra communication between the "server" and "user" layers). bind(): * bind() does not work on broadcast packets, IP_UNICAST_IF is specifically intended to work with broadcast packets. * Like SO_BINDTODEVICE, bind() restricts both outbound and inbound traffic. Signed-off-by: Erich E. Hoover Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller