Re: [rfc/rft][patch] should use scheduler sync hint intcp_prequeue()?

From: Mike Galbraith
Date: Wed Mar 03 2010 - 09:46:59 EST

On Wed, 2010-03-03 at 06:05 -0800, David Miller wrote:

> It definitely looks like an oversight to me and we should add
> be using wake_up_interruptible_sync_poll() in tcp_prequeue()
> as above.
> Ingo?

Implied ack from network maintainer implies ship it to me.

net: add scheduler sync hint to tcp_prequeue().

Decreases the odds wakee will suffer from frequent cache misses.

Signed-off-by: Mike Galbraith <efault@xxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
LKML-Reference: <new-submission>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 34f5cc2..ba3fc64 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -939,7 +939,7 @@ static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)

tp->ucopy.memory = 0;
} else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
- wake_up_interruptible_poll(sk->sk_sleep,
+ wake_up_interruptible_sync_poll(sk->sk_sleep,
if (!inet_csk_ack_scheduled(sk))
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,

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