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From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: haiyangz@microsoft.com, edumazet@google.com,
	netdev@vger.kernel.org, kys@microsoft.com
Subject: Re: [PATCH net-next] net: increase LL_MAX_HEADER if HYPERV_NET is enabled
Date: Sun, 01 Nov 2015 14:36:20 -0800	[thread overview]
Message-ID: <1446417380.6254.93.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <20151101.155859.1206189858863918018.davem@davemloft.net>

On Sun, 2015-11-01 at 15:58 -0500, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Sun, 01 Nov 2015 09:20:59 -0800
> 
> > From: Eric Dumazet <edumazet@google.com>
> > 
> > My recent commit, attaching SYNACK messages to request sockets
> > exposed a too small LL_MAX_HEADER when netvsc_drv.c is in use,
> > because this driver sets a needed_headroom of 220 bytes.
> > 
> > Increase LL_MAX_HEADER in this case, to avoid a realloc of all
> > TCP frames.
> > 
> > In another patch, I'll make skb_set_owner_w() more robust.
> > 
> > Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
> > Bisected-by: Haiyang Zhang <haiyangz@microsoft.com>
> 
> Using a value of 256 just because HYPER-V is crazy imposes a huge
> unnecessary burdon upon the rest of the stack.
> 
> I rejected a previous attempt to use such a huge value for
> LL_MAX_HEADER, and I will do so again here.  We need a different fix
> for this issue, one that doesn't hurt everyone.

Sure, I was planning to send the skb_set_owner_w() fix as well.

I was not aware you already objected to LL_MAX_HEADER increase.

  reply	other threads:[~2015-11-01 22:36 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-29 21:49 [patch] tcp: attach SYNACK messages to request sockets instead of listener Haiyang Zhang
2015-10-29 22:58 ` Eric Dumazet
2015-10-30 19:38   ` Haiyang Zhang
2015-10-30 20:02     ` Eric Dumazet
2015-10-30 20:18       ` Eric Dumazet
2015-10-30 21:42         ` Haiyang Zhang
2015-10-30 23:52           ` Eric Dumazet
2015-11-01 17:20             ` [PATCH net-next] net: increase LL_MAX_HEADER if HYPERV_NET is enabled Eric Dumazet
2015-11-01 20:58               ` David Miller
2015-11-01 22:36                 ` Eric Dumazet [this message]
2015-11-01 22:58                   ` [PATCH net-next] net: make skb_set_owner_w() more robust Eric Dumazet
2015-11-01 23:18                     ` kbuild test robot
2015-11-01 23:27                       ` Eric Dumazet
2015-11-01 23:36                     ` [PATCH v2 " Eric Dumazet
2015-11-02 20:05                       ` Haiyang Zhang
2015-11-02 20:09                         ` Eric Dumazet
2015-11-02 20:26                           ` David Miller
2015-11-02 21:29                       ` David Miller
2015-11-03  7:59                 ` [PATCH net-next] net: increase LL_MAX_HEADER if HYPERV_NET is enabled KY Srinivasan
2015-11-03 15:33                   ` David Miller
2015-11-03 16:37                     ` Eric Dumazet
2015-11-03 17:34                       ` Haiyang Zhang
2015-11-03 18:20                         ` David Miller
2015-11-03 18:49                           ` Haiyang Zhang
2015-11-03 19:50                             ` David Miller
2015-11-03 21:00                               ` Haiyang Zhang
2015-11-03 18:09                     ` KY Srinivasan
2015-10-30 20:28       ` [patch] tcp: attach SYNACK messages to request sockets instead of listener KY Srinivasan

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