From 70da268b569d32a9fddeea85dc18043de9d89f89 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 8 Oct 2015 19:33:21 -0700 Subject: [PATCH] net: SO_INCOMING_CPU setsockopt() support SO_INCOMING_CPU as added in commit 2c8c56e15df3 was a getsockopt() command to fetch incoming cpu handling a particular TCP flow after accept() This commits adds setsockopt() support and extends SO_REUSEPORT selection logic : If a TCP listener or UDP socket has this option set, a packet is delivered to this socket only if CPU handling the packet matches the specified one. This allows to build very efficient TCP servers, using one listener per RX queue, as the associated TCP listener should only accept flows handled in softirq by the same cpu. This provides optimal NUMA behavior and keep cpu caches hot. Note that __inet_lookup_listener() still has to iterate over the list of all listeners. Following patch puts sk_refcnt in a different cache line to let this iteration hit only shared and read mostly cache lines. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/sock.h | 10 ++++------ net/core/sock.c | 5 +++++ net/ipv4/inet_hashtables.c | 2 ++ net/ipv4/udp.c | 6 +++++- net/ipv6/inet6_hashtables.c | 2 ++ net/ipv6/udp.c | 11 +++++++---- 6 files changed, 25 insertions(+), 11 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 9322cafd191b..cf54739f30d5 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -150,6 +150,7 @@ typedef __u64 __bitwise __addrpair; * @skc_node: main hash linkage for various protocol lookup tables * @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol * @skc_tx_queue_mapping: tx queue number for this connection + * @skc_incoming_cpu: record/match cpu processing incoming packets * @skc_refcnt: reference count * * This is the minimal network layer representation of sockets, the header @@ -212,6 +213,8 @@ struct sock_common { struct hlist_nulls_node skc_nulls_node; }; int skc_tx_queue_mapping; + int skc_incoming_cpu; + atomic_t skc_refcnt; /* private: */ int skc_dontcopy_end[0]; @@ -274,7 +277,6 @@ struct cg_proto; * @sk_rcvtimeo: %SO_RCVTIMEO setting * @sk_sndtimeo: %SO_SNDTIMEO setting * @sk_rxhash: flow hash received from netif layer - * @sk_incoming_cpu: record cpu processing incoming packets * @sk_txhash: computed flow hash for use on transmit * @sk_filter: socket filtering instructions * @sk_timer: sock cleanup timer @@ -331,6 +333,7 @@ struct sock { #define sk_v6_daddr __sk_common.skc_v6_daddr #define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr #define sk_cookie __sk_common.skc_cookie +#define sk_incoming_cpu __sk_common.skc_incoming_cpu socket_lock_t sk_lock; struct sk_buff_head sk_receive_queue; @@ -353,11 +356,6 @@ struct sock { #ifdef CONFIG_RPS __u32 sk_rxhash; #endif - u16 sk_incoming_cpu; - /* 16bit hole - * Warned : sk_incoming_cpu can be set from softirq, - * Do not use this hole without fully understanding possible issues. - */ __u32 sk_txhash; #ifdef CONFIG_NET_RX_BUSY_POLL diff --git a/net/core/sock.c b/net/core/sock.c index 33957776cc1a..dcc7d62654d5 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -988,6 +988,10 @@ set_rcvbuf: sk->sk_max_pacing_rate); break; + case SO_INCOMING_CPU: + sk->sk_incoming_cpu = val; + break; + default: ret = -ENOPROTOOPT; break; @@ -2379,6 +2383,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_max_pacing_rate = ~0U; sk->sk_pacing_rate = ~0U; + sk->sk_incoming_cpu = -1; /* * Before updating sk_refcnt, we must commit prior changes to memory * (Documentation/RCU/rculist_nulls.txt for details) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index bed8886a4b6c..08643a3616af 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -185,6 +185,8 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score += 4; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; } return score; } diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e1fc129099ea..24ec14f9825c 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -375,7 +375,8 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score += 4; } - + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; return score; } @@ -419,6 +420,9 @@ static inline int compute_score2(struct sock *sk, struct net *net, score += 4; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; + return score; } diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 6ac8dad0138a..21ace5a2bf7c 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -114,6 +114,8 @@ static inline int compute_score(struct sock *sk, struct net *net, return -1; score++; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; } return score; } diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 0aba654f5b91..01bcb49619ee 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -182,10 +182,12 @@ static inline int compute_score(struct sock *sk, struct net *net, score++; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; + return score; } -#define SCORE2_MAX (1 + 1 + 1) static inline int compute_score2(struct sock *sk, struct net *net, const struct in6_addr *saddr, __be16 sport, const struct in6_addr *daddr, @@ -223,6 +225,9 @@ static inline int compute_score2(struct sock *sk, struct net *net, score++; } + if (sk->sk_incoming_cpu == raw_smp_processor_id()) + score++; + return score; } @@ -251,8 +256,7 @@ begin: hash = udp6_ehashfn(net, daddr, hnum, saddr, sport); matches = 1; - } else if (score == SCORE2_MAX) - goto exact_match; + } } else if (score == badness && reuseport) { matches++; if (reciprocal_scale(hash, matches) == 0) @@ -269,7 +273,6 @@ begin: goto begin; if (result) { -exact_match: if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2))) result = NULL; else if (unlikely(compute_score2(result, net, saddr, sport, -- 2.20.1