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authorPaolo Abeni <pabeni@redhat.com>2016-12-02 17:35:49 +0100
committerDavid S. Miller <davem@davemloft.net>2016-12-03 16:14:48 -0500
commit363dc73acacbbcdae98acf5612303e9770e04b1d (patch)
tree68077749dd6983143b8c58a8167ccbdb2448f7c7
parent12efa1fa43968fcb707e806dc119df499c17ac2c (diff)
downloadlinux-363dc73acacbbcdae98acf5612303e9770e04b1d.tar.bz2
udp: be less conservative with sock rmem accounting
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> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/udp.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e1d0bf8eba4b..16d88ba9ff1c 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);