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From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: David Miller <davem@davemloft.net>, tom@herbertland.com
Cc: netdev@vger.kernel.org, kernel-team@fb.com, davewatson@fb.com,
	alexei.starovoitov@gmail.com
Subject: Re: [PATCH net-next 0/6] kcm: Kernel Connection Multiplexor (KCM)
Date: Tue, 24 Nov 2015 12:25:39 +0100	[thread overview]
Message-ID: <87y4dnfxl8.fsf@stressinduktion.org> (raw)
In-Reply-To: <20151123.145433.1554000376541433305.davem@davemloft.net>

Hello,

David Miller <davem@davemloft.net> writes:

> From: Tom Herbert <tom@herbertland.com>
> Date: Mon, 23 Nov 2015 09:33:44 -0800
>
>> The TCP PSH flag is not defined for message delineation (neither is
>> urgent pointer). We can't change that (many people have tried to add
>> message semantics to TCP protocol but have always failed miserably).
>
> Agreed.
>
> My only gripe with kcm right now is a lack of a native sendpage.
> We should be able to zero copy data through KCM streams without
> any problems whatsoever.

I understood from Tom's last mail that the messages are being
constructed *in kernel memory* before sending out of the tcp
socket. What advantage gives sendpage? The message construction must
actually happen before to fill in the necessary headers for the length,
so receiver can dissect again. Streaming semantics don't really fit
here?

Bye,
Hannes

  parent reply	other threads:[~2015-11-24 11:25 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-20 21:21 [PATCH net-next 0/6] kcm: Kernel Connection Multiplexor (KCM) Tom Herbert
2015-11-20 21:21 ` [PATCH net-next 1/6] rcu: Add list_next_or_null_rcu Tom Herbert
2015-11-20 21:21 ` [PATCH net-next 2/6] net: Make sock_alloc exportable Tom Herbert
2015-11-20 21:21 ` [PATCH net-next 3/6] net: Add MSG_BATCH flag Tom Herbert
2015-11-23 10:02   ` Hannes Frederic Sowa
2015-11-20 21:21 ` [PATCH net-next 4/6] kcm: Kernel Connection Multiplexor module Tom Herbert
2015-11-20 22:50   ` Sowmini Varadhan
2015-11-20 23:19     ` Tom Herbert
2015-11-20 23:27       ` Sowmini Varadhan
2015-11-20 23:10   ` Alexei Starovoitov
2015-11-20 23:20     ` Tom Herbert
2015-11-23  9:42   ` Daniel Borkmann
2015-11-20 21:21 ` [PATCH net-next 5/6] kcm: Add statistics and proc interfaces Tom Herbert
2015-11-20 21:22 ` [PATCH net-next 6/6] kcm: Add description in Documentation Tom Herbert
2015-11-23  9:53 ` [PATCH net-next 0/6] kcm: Kernel Connection Multiplexor (KCM) Hannes Frederic Sowa
2015-11-23 12:43   ` Sowmini Varadhan
2015-11-23 17:33   ` Tom Herbert
2015-11-23 19:35     ` Hannes Frederic Sowa
2015-11-23 19:54     ` David Miller
2015-11-23 20:02       ` Tom Herbert
2015-11-24 11:25       ` Hannes Frederic Sowa [this message]
2015-11-24 15:49         ` David Miller
2015-11-24 15:27       ` Florian Westphal
2015-11-24 15:49         ` Eric Dumazet
2015-11-24 18:09           ` Rick Jones
2015-11-24 15:55         ` David Miller
2015-11-24 16:25           ` Florian Westphal
2015-11-24 17:00             ` Tom Herbert
2015-11-24 17:16               ` Florian Westphal
2015-11-24 17:43                 ` Tom Herbert
2015-11-24 20:55                   ` Florian Westphal
2015-11-24 21:49                     ` Tom Herbert
2015-11-24 22:22                       ` Florian Westphal
2015-11-24 22:25                         ` David Miller
2015-11-24 22:45                           ` Florian Westphal
2015-11-24 23:13                           ` Hannes Frederic Sowa
2015-11-24 18:23             ` Hannes Frederic Sowa
2015-11-24 18:59               ` Alexei Starovoitov
2015-11-24 19:16                 ` Hannes Frederic Sowa
2015-11-24 19:26                   ` Hannes Frederic Sowa
2015-11-24 20:23                   ` Alexei Starovoitov
     [not found]                     ` <1448402288.1489559.449199721.64EBB346@webmail.messagingengine.com>
     [not found]                       ` <20151124222109.GA86838@ast-mbp.thefacebook.com>
2015-11-25 10:38                         ` Hannes Frederic Sowa
2015-11-25 16:26             ` Sowmini Varadhan

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