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authorEric Dumazet <edumazet@google.com>2014-10-10 18:06:35 -0700
committerDavid S. Miller <davem@davemloft.net>2014-10-14 13:12:00 -0400
commitb2532eb9abd88384aa586169b54a3e53574f29f8 (patch)
treef46795756a2b89adab83759a4e47befd8ba8aba6 /net
parent31eff81e94472ddb7549509bf4b6e93e1f6f7dc9 (diff)
tcp: fix ooo_okay setting vs Small Queues
TCP Small Queues (tcp_tsq_handler()) can hold one reference on sk->sk_wmem_alloc, preventing skb->ooo_okay being set. We should relax test done to set skb->ooo_okay to take care of this extra reference. Minimal truesize of skb containing one byte of payload is SKB_TRUESIZE(1) Without this fix, we have more chance locking flows into the wrong transmit queue. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_output.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 8d4eac793700..0a5d97c20aa9 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -914,9 +914,13 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
tcp_ca_event(sk, CA_EVENT_TX_START);
/* if no packet is in qdisc/device queue, then allow XPS to select
- * another queue.
+ * another queue. We can be called from tcp_tsq_handler()
+ * which holds one reference to sk_wmem_alloc.
+ *
+ * TODO: Ideally, in-flight pure ACK packets should not matter here.
+ * One way to get this would be to set skb->truesize = 2 on them.
*/
- skb->ooo_okay = sk_wmem_alloc_get(sk) == 0;
+ skb->ooo_okay = sk_wmem_alloc_get(sk) < SKB_TRUESIZE(1);
skb_push(skb, tcp_header_size);
skb_reset_transport_header(skb);