diff mbox

[net] udp: inuse checks can quit early for reuseport

Message ID 20170106012236.20078-1-e@erig.me
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Eric Garver Jan. 6, 2017, 1:22 a.m. UTC
UDP lib inuse checks will walk the entire hash bucket to check if the
portaddr is in use. In the case of reuseport we can stop searching when
we find a matching reuseport.

On a 16-core VM a test program that spawns 16 threads that each bind to
1024 sockets (one per 10ms) takes 1m45s. With this change it takes 11s.

Also add a cond_resched() when the port is not specified.

Signed-off-by: Eric Garver <e@erig.me>
---
 net/ipv4/udp.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

Comments

David Miller Jan. 7, 2017, 1:57 a.m. UTC | #1
From: Eric Garver <e@erig.me>
Date: Thu,  5 Jan 2017 20:22:36 -0500

> UDP lib inuse checks will walk the entire hash bucket to check if the
> portaddr is in use. In the case of reuseport we can stop searching when
> we find a matching reuseport.
> 
> On a 16-core VM a test program that spawns 16 threads that each bind to
> 1024 sockets (one per 10ms) takes 1m45s. With this change it takes 11s.
> 
> Also add a cond_resched() when the port is not specified.
> 
> Signed-off-by: Eric Garver <e@erig.me>

Applied to net-next.
diff mbox

Patch

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 1307a7c2e544..4318d72e0248 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -153,13 +153,18 @@  static int udp_lib_lport_inuse(struct net *net, __u16 num,
 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
-		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
-		     rcu_access_pointer(sk->sk_reuseport_cb) ||
-		     !uid_eq(uid, sock_i_uid(sk2))) &&
 		    saddr_comp(sk, sk2, true)) {
-			if (!bitmap)
-				return 1;
-			__set_bit(udp_sk(sk2)->udp_port_hash >> log, bitmap);
+			if (sk2->sk_reuseport && sk->sk_reuseport &&
+			    !rcu_access_pointer(sk->sk_reuseport_cb) &&
+			    uid_eq(uid, sock_i_uid(sk2))) {
+				if (!bitmap)
+					return 0;
+			} else {
+				if (!bitmap)
+					return 1;
+				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
+					  bitmap);
+			}
 		}
 	}
 	return 0;
@@ -188,11 +193,14 @@  static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
-		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
-		     rcu_access_pointer(sk->sk_reuseport_cb) ||
-		     !uid_eq(uid, sock_i_uid(sk2))) &&
 		    saddr_comp(sk, sk2, true)) {
-			res = 1;
+			if (sk2->sk_reuseport && sk->sk_reuseport &&
+			    !rcu_access_pointer(sk->sk_reuseport_cb) &&
+			    uid_eq(uid, sock_i_uid(sk2))) {
+				res = 0;
+			} else {
+				res = 1;
+			}
 			break;
 		}
 	}
@@ -285,6 +293,7 @@  int udp_lib_get_port(struct sock *sk, unsigned short snum,
 				snum += rand;
 			} while (snum != first);
 			spin_unlock_bh(&hslot->lock);
+			cond_resched();
 		} while (++first != last);
 		goto fail;
 	} else {