Apply patch for socken listen backlog (FreeBSD)

[Volker Lendecke]

On Fri, Jan 11, 2019 at 01:29:54PM -0500, Andrew Walker via samba-technical wrote:
> This is perhaps a more targeted fix for FreeBSD. If a 'backlog' value of
> less than zero is specified, then the backlog is silently forced to
> kern.ipc.soacceptqueue on FreeBSD. Do note that we have observed
> significant problems in large environments on FreeBSD that required this
> change, and so there is definitely merit in addressing it in some way.

This change looks of course ok. I'm not sure I like the #ifdef
FREEBSD, but if this is really something FreeBSD specific, then it
might be the right way to go.

I'd like to understand the patch and its necessity a bit better. The
listen backlog copes with the process doing the accept() being too
slow, right? Where exactly do you see the problems, where is smbd or
winbind too slow? The smbd process doing the accept should not do much
work before doing the fork, returning to polling the acceptor socket.
What is the scenario that you're fixing with this? If the parent smbd
does significant work between the accept calls, I think we also need
to fix that. Likewise for winbind.

What is it that makes this a FreeBSD specific problem?

Volker

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