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Date: Tue, 23 Oct 2012 18:38:52 +0200
From: Andre Oppermann <andre@freebsd.org>
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To: Gleb Smirnoff <glebius@FreeBSD.org>
Subject: Re: svn commit: r241931 - in head/sys: conf kern
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On 23.10.2012 18:05, Gleb Smirnoff wrote:
> On Tue, Oct 23, 2012 at 05:05:48PM +0200, Andre Oppermann wrote:
> A> There shouldn't be any users.  Zero copy send is broken and
> A> responsible for random kernel crashes.  Zero copy receive isn't
> A> supported by any modern driver.  Both are useless to dangerous.
> A>
> A> The main problem with ZERO_COPY_SOCKETS was that it sounded great
> A> and who wouldn't want to have zero copy sockets?  Unfortunately
> A> it doesn't work that way.
>
> Okay, it appeared that there are users, even on current@ mailing
> list during couple of hours of exposition.
>
> Can we keep the old option as compatibility?

No.  They are not users.  They simply fell for the promise of
"zero copy" which it isn't.  It doesn't do what the "users"
believe it does.  It's useless for receive and dangerous for send.

I have updated NOTES and forwarded it to -current.

-- 
Andre