| Message ID | d13b9808dad5f6e3fe3808bae3b4f64dfcee07fe.1480696423.git.pabeni@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Paolo Abeni <pabeni@redhat.com> Date: Fri, 2 Dec 2016 17:35:49 +0100 > Before commit 850cbaddb52d ("udp: use it's own memory accounting > schema"), the udp protocol allowed sk_rmem_alloc to grow beyond > the rcvbuf by the whole current packet's truesize. After said commit > we allow sk_rmem_alloc to exceed the rcvbuf only if the receive queue > is empty. As reported by Jesper this cause a performance regression > for some (small) values of rcvbuf. > > This commit is intended to fix the regression restoring the old > handling of the rcvbuf limit. > > Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> > Fixes: 850cbaddb52d ("udp: use it's own memory accounting schema") > Signed-off-by: Paolo Abeni <pabeni@redhat.com> Applied.
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e1d0bf8..16d88ba 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1205,14 +1205,14 @@ int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb) * queue is full; always allow at least a packet */ rmem = atomic_read(&sk->sk_rmem_alloc); - if (rmem && (rmem + size > sk->sk_rcvbuf)) + if (rmem > sk->sk_rcvbuf) goto drop; /* we drop only if the receive buf is full and the receive * queue contains some other skb */ rmem = atomic_add_return(size, &sk->sk_rmem_alloc); - if ((rmem > sk->sk_rcvbuf) && (rmem > size)) + if (rmem > (size + sk->sk_rcvbuf)) goto uncharge_drop; spin_lock(&list->lock);
Before commit 850cbaddb52d ("udp: use it's own memory accounting schema"), the udp protocol allowed sk_rmem_alloc to grow beyond the rcvbuf by the whole current packet's truesize. After said commit we allow sk_rmem_alloc to exceed the rcvbuf only if the receive queue is empty. As reported by Jesper this cause a performance regression for some (small) values of rcvbuf. This commit is intended to fix the regression restoring the old handling of the rcvbuf limit. Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> Fixes: 850cbaddb52d ("udp: use it's own memory accounting schema") Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- net/ipv4/udp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)