From ca065d0cf80fa547724440a8bf37f1e674d917c0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 Apr 2016 08:52:13 -0700 Subject: udp: no longer use SLAB_DESTROY_BY_RCU Tom Herbert would like not touching UDP socket refcnt for encapsulated traffic. For this to happen, we need to use normal RCU rules, with a grace period before freeing a socket. UDP sockets are not short lived in the high usage case, so the added cost of call_rcu() should not be a concern. This actually removes a lot of complexity in UDP stack. Multicast receives no longer need to hold a bucket spinlock. Note that ip early demux still needs to take a reference on the socket. Same remark for functions used by xt_socket and xt_PROXY netfilter modules, but this might be changed later. Performance for a single UDP socket receiving flood traffic from many RX queues/cpus. Simple udp_rx using simple recvfrom() loop : 438 kpps instead of 374 kpps : 17 % increase of the peak rate. v2: Addressed Willem de Bruijn feedback in multicast handling - keep early demux break in __udp4_lib_demux_lookup() Signed-off-by: Eric Dumazet Cc: Tom Herbert Cc: Willem de Bruijn Tested-by: Tom Herbert Signed-off-by: David S. Miller --- include/net/sock.h | 12 ++++++------ include/net/udp.h | 2 +- 2 files changed, 7 insertions(+), 7 deletions(-) (limited to 'include/net') diff --git a/include/net/sock.h b/include/net/sock.h index 9e77353a92ae..7ad73db9dde2 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -178,7 +178,7 @@ struct sock_common { int skc_bound_dev_if; union { struct hlist_node skc_bind_node; - struct hlist_nulls_node skc_portaddr_node; + struct hlist_node skc_portaddr_node; }; struct proto *skc_prot; possible_net_t skc_net; @@ -670,18 +670,18 @@ static inline void sk_add_bind_node(struct sock *sk, hlist_for_each_entry(__sk, list, sk_bind_node) /** - * sk_nulls_for_each_entry_offset - iterate over a list at a given struct offset + * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_node to use as a loop cursor. * @head: the head for your list. * @offset: offset of hlist_node within the struct. * */ -#define sk_nulls_for_each_entry_offset(tpos, pos, head, offset) \ - for (pos = (head)->first; \ - (!is_a_nulls(pos)) && \ +#define sk_for_each_entry_offset_rcu(tpos, pos, head, offset) \ + for (pos = rcu_dereference((head)->first); \ + pos != NULL && \ ({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;}); \ - pos = pos->next) + pos = rcu_dereference(pos->next)) static inline struct user_namespace *sk_user_ns(struct sock *sk) { diff --git a/include/net/udp.h b/include/net/udp.h index 92927f729ac8..d870ec1611c4 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -59,7 +59,7 @@ struct udp_skb_cb { * @lock: spinlock protecting changes to head/count */ struct udp_hslot { - struct hlist_nulls_head head; + struct hlist_head head; int count; spinlock_t lock; } __attribute__((aligned(2 * sizeof(long)))); -- cgit v1.2.3