path: root/net/ipv4/tcp_timer.c
diff options
authorFlorian Westphal <fw@strlen.de>2017-07-30 03:57:18 +0200
committerDavid S. Miller <davem@davemloft.net>2017-07-31 14:37:49 -0700
commite7942d0633c47c791ece6afa038be9cf977226de (patch)
tree27dddb46a5358137f6cb6e63bddab14a77a840ec /net/ipv4/tcp_timer.c
parentMerge branch 'net-sched-actions-improve-dump-performance' (diff)
tcp: remove prequeue support
prequeue is a tcp receive optimization that moves part of rx processing from bh to process context. This only works if the socket being processed belongs to a process that is blocked in recv on that socket. In practice, this doesn't happen anymore that often because nowadays servers tend to use an event driven (epoll) model. Even normal client applications (web browsers) commonly use many tcp connections in parallel. This has measureable impact only in netperf (which uses plain recv and thus allows prequeue use) from host to locally running vm (~4%), however, there were no changes when using netperf between two physical hosts with ixgbe interfaces. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
1 files changed, 0 insertions, 12 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index c0feeeef962a..f753f9d2fee3 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -239,7 +239,6 @@ static int tcp_write_timeout(struct sock *sk)
/* Called with BH disabled */
void tcp_delack_timer_handler(struct sock *sk)
- struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
@@ -254,17 +253,6 @@ void tcp_delack_timer_handler(struct sock *sk)
icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
- if (!skb_queue_empty(&tp->ucopy.prequeue)) {
- struct sk_buff *skb;
- while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
- sk_backlog_rcv(sk, skb);
- tp->ucopy.memory = 0;
- }
if (inet_csk_ack_scheduled(sk)) {
if (!icsk->icsk_ack.pingpong) {
/* Delayed ACK missed: inflate ATO. */