netdev - Re: [PATCH net-next v1] gso: Support partial splitting at the frag

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Message-ID: <20160827104711.46f73c12@halley>
Date:   Sat, 27 Aug 2016 10:47:11 +0300
From:   Shmulik Ladkani <shmulik.ladkani@...il.com>
To:     Alexander Duyck <alexander.duyck@...il.com>
Cc:     Steffen Klassert <steffen.klassert@...unet.com>,
        Netdev <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Alexander Duyck <alexander.h.duyck@...el.com>,
        Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Subject: Re: [PATCH net-next v1] gso: Support partial splitting at the
 frag_list pointer

Hi,

On Fri, 26 Aug 2016 13:45:56 -0700 Alexander Duyck <alexander.duyck@...il.com> wrote:
> > However, if TSO is off, but GSO is on, who takes care of further
> > splitting these skbs according to their gso_size?  
> 
> I believe the patch resolves it via the net_gso_ok check.  This is
> used to verify if the lower device could segment it if we split out
> the buffers from skb->frag_list.

Thanks, got it.

> > And another question:
> > Can this be utilized in any way to solve the problem described in [1] ?
> >
> > [1] https://patchwork.ozlabs.org/patch/661419/  
> 
> I don't think so.  This solution is to only do part of the software
> offload and still make use of an existing hardware offload.

Sorry, I wasn't too clear.

When attempting to reduce gso_size in order to avoid
segmentation+fragmentation, problem I'm hitting is:
  http://lists.openwall.net/netdev/2016/08/25/35

Actually, the idea of yours hinted me to a new direction, will pursue
that.

Thanks,
Shmulik