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 <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 87c0949..3234275 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -98,11 +98,11 @@
return udp_sk(sk)->no_check6_rx;
}
-#define udp_portaddr_for_each_entry(__sk, node, list) \
- hlist_nulls_for_each_entry(__sk, node, list, __sk_common.skc_portaddr_node)
+#define udp_portaddr_for_each_entry(__sk, list) \
+ hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
-#define udp_portaddr_for_each_entry_rcu(__sk, node, list) \
- hlist_nulls_for_each_entry_rcu(__sk, node, list, __sk_common.skc_portaddr_node)
+#define udp_portaddr_for_each_entry_rcu(__sk, list) \
+ hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
#define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)