From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Eric Dumazet <eric.dumazet@gmail.com>,
Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
James Morris <jmorris@namei.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Patrick McHardy <kaber@trash.net>,
"open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Haakon Bugge <haakon.bugge@oracle.com>
Subject: Re: [PATCH v2] net:Add sysctl_tcp_sg_max_skb_frags
Date: Wed, 27 Jan 2016 19:12:12 +0100 [thread overview]
Message-ID: <56A9087C.20305@stressinduktion.org> (raw)
In-Reply-To: <1453907702.20722.6.camel@edumazet-glaptop2.roam.corp.google.com>
On 27.01.2016 16:15, Eric Dumazet wrote:
> On Wed, 2016-01-27 at 14:20 +0100, Hans Westgaard Ry wrote:
>> Devices may have limits on the number of fragments in an skb they support.
>> Current codebase uses a constant as maximum for number of fragments one
>> skb can hold and use.
>> When enabling scatter/gather and running traffic with many small messages
>> the codebase uses the maximum number of fragments and may thereby violate
>> the max for certain devices.
>> The patch introduces a global variable as max number of fragments in
>> scatter/gather.
>
>
> Principle looks good, but we have to ask if other skb providers [1] will
> add other sysctl, or if we could share a common one ?
>
> If it is a common one, it should be /proc/sys/net/core/... instead
> of /proc/sys/net/ipv4/tcp_....
>
> Other providers include :
>
> 1) GRO stack
> 2) callers of sock_alloc_send_pskb(), alloc_skb_with_frags(),
> sock_alloc_send_skb() ..
I agree, this knob should get a generic name and live in a generic net/
directory to control this globally, so things don't break during
forwarding etc.
It does not solve the problem completely, e.g. when VMs send gso packets
through a vhost-net onto IPoIB, no?
Thanks,
Hannes
next prev parent reply other threads:[~2016-01-27 18:12 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 13:16 [PATCH] net: add per device sg_max_frags for skb Hans Westgaard Ry
2016-01-06 13:59 ` David Laight
2016-01-08 9:55 ` Hans Westgaard Ry
2016-01-08 10:33 ` David Laight
2016-01-08 11:47 ` Hannes Frederic Sowa
2016-01-13 13:57 ` Hans Westgaard Ry
2016-01-13 14:19 ` Eric Dumazet
2016-01-13 14:20 ` Eric Dumazet
2016-01-13 15:07 ` Hannes Frederic Sowa
2016-01-13 15:38 ` David Miller
2016-01-13 15:44 ` Eric Dumazet
2016-01-13 21:07 ` Eric W. Biederman
2016-01-27 13:20 ` [PATCH v2] net:Add sysctl_tcp_sg_max_skb_frags Hans Westgaard Ry
2016-01-27 15:15 ` Eric Dumazet
2016-01-27 18:12 ` Hannes Frederic Sowa [this message]
2016-02-01 13:12 ` Hans Westgaard Ry
2016-01-27 20:13 ` David Miller
2016-02-03 8:26 ` [PATCH v3] net:Add sysctl_max_skb_frags Hans Westgaard Ry
2016-02-03 11:25 ` Herbert Xu
2016-02-03 11:36 ` Hannes Frederic Sowa
2016-02-03 12:20 ` Herbert Xu
2016-02-03 14:03 ` Hannes Frederic Sowa
2016-02-03 14:30 ` Eric Dumazet
2016-02-03 17:36 ` David Laight
2016-02-03 15:58 ` Alexander Duyck
2016-02-03 16:07 ` Eric Dumazet
2016-02-03 17:43 ` Alexander Duyck
2016-02-03 17:54 ` Eric Dumazet
2016-02-03 18:24 ` Alexander Duyck
2016-02-03 19:23 ` Eric Dumazet
2016-02-03 21:03 ` Alexander Duyck
2016-02-09 9:30 ` David Miller
2016-01-06 14:05 ` [PATCH] net: add per device sg_max_frags for skb Eric Dumazet
2016-01-08 10:01 ` Hans Westgaard Ry
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