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From: Andi Kleen <ak@suse.de>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Andi Kleen <ak@suse.de>,
	hadi@cyberus.ca, davem@redhat.com, netdev@oss.sgi.com
Subject: Re: [PATCH] NETIF_F_LLTX for devices 2
Date: Wed, 8 Sep 2004 09:24:08 +0200	[thread overview]
Message-ID: <20040908072408.GI27886@wotan.suse.de> (raw)
In-Reply-To: <E1C4wYe-0005qT-00@gondolin.me.apana.org.au>

On Wed, Sep 08, 2004 at 05:07:56PM +1000, Herbert Xu wrote:
> Andi Kleen <ak@suse.de> wrote:
> >
> >> 1: means packet was not put on the ring. i.e if you return
> >> 1, the toplayer will retry later with the same skb. 
> >> [of course If you stash it on the ring, the danger is tx complete will
> >> try to free it later while the toplayer code is still referencing it. A
> >> good oops].
> > 
> > Actually when you return 1 then the kernel prints an ugly 
> > message and it is considered a bug.  Here -1 is legal.
> 
> 1 is legal in contexts where queueing occurs.  See for example
> qdisc_restart().

I agree my sentence was misleading. 

Basically the distinction here is:

1 is for flow control 
-1 is for lock contention

I think it's better to separate them because it minimizes the risk
of breaking old drivers.

> 
> It's only illegal here because this is the direct xmit path without
> queueing.

You are thinking of the wrong patch. This patch is changing qdisc_restart

-Andi

  reply	other threads:[~2004-09-08  7:24 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-07 12:05 [PATCH] NETIF_F_LLTX for devices 2 Andi Kleen
2004-09-07 21:39 ` David S. Miller
2004-09-07 21:53 ` jamal
2004-09-08  6:51   ` Andi Kleen
2004-09-08  7:07     ` Herbert Xu
2004-09-08  7:24       ` Andi Kleen [this message]
2004-09-08  7:47         ` jamal
2004-09-08 20:47           ` David S. Miller
2004-09-10 13:33             ` jamal
2004-09-10 23:02               ` David S. Miller
2004-09-11 14:21               ` Andi Kleen
2004-09-11 20:15                 ` jamal
2004-09-12  0:45                   ` David S. Miller
2004-09-12  9:57                     ` Jeff Garzik
2004-09-12 10:01                     ` Jeff Garzik
2004-09-12 10:25                       ` Andi Kleen
2004-09-12 11:03                         ` Francois Romieu
2004-09-13  0:13                           ` David S. Miller
2004-09-12 16:16                         ` Jeff Garzik
2004-09-12 17:34                           ` jamal
2004-09-13  0:06                             ` Jeff Garzik
2004-09-13  0:10                             ` David S. Miller
2004-09-13  2:52                             ` Andrew Grover
2004-09-13  6:59                           ` Andi Kleen
2004-09-13 16:10                             ` Jeff Garzik
2004-09-13  0:12                         ` Jeff Garzik

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