From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
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 15:58:59 -0500 (EST) [thread overview]
Message-ID: <20151101.155859.1206189858863918018.davem@davemloft.net> (raw)
In-Reply-To: <1446398459.6254.90.camel@edumazet-glaptop2.roam.corp.google.com>
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.
Every distribution is going to turn all the options on, so you might
as well consider the largest LL_MAX_HEADER value the one %99.999
users end up paying the price for.
next prev parent reply other threads:[~2015-11-01 20:59 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 [this message]
2015-11-01 22:36 ` Eric Dumazet
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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