* Eric Dumazet [off-list ref] wrote:

I noticed some paths in kernel are very stack aggressive, and on i386 
with CONFIG_4KSTACKS we were really in a dangerous land, even without 
my patch.

What we call 4K stacks is in fact 4K - sizeof(struct task_struct), so 
a litle bit more than 2K. [...]

that's just wrong - 4K stacks on x86 are 4K-sizeof(thread_info) - the 
task struct is allocated elsewhere. The patch below runs just fine on 
4K-stack x86.

	Ingo

------------->
Subject: net: loopback speedup
From: Ingo Molnar <redacted>
Date: Mon Mar 31 11:23:21 CEST 2008

Signed-off-by: Ingo Molnar <redacted>
---
 drivers/net/loopback.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/drivers/net/loopback.c
===================================================================

--- linux.orig/drivers/net/loopback.c
+++ linux/drivers/net/loopback.c

@@ -158,7 +158,7 @@ static int loopback_xmit(struct sk_buff 
 	lb_stats->bytes += skb->len;
 	lb_stats->packets++;
 
-	netif_rx(skb);
+	netif_receive_skb(skb);
 
 	return 0;
 }