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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Ivan Voras <ivoras@freebsd.org>
References: <ghjt9l$hg3$1@ger.gmane.org>
Date: Wed, 10 Dec 2008 12:21:24 +0100
In-Reply-To: <ghjt9l$hg3$1@ger.gmane.org> (Ivan Voras's message of "Mon, 08
	Dec 2008 20:41:32 +0100")
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Cc: freebsd-hackers@freebsd.org
Subject: Re: MAXFILES in subr_param.c
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Ivan Voras <ivoras@freebsd.org> writes:
> I'm looking at kern/subr_param.c:
>
>  72 #ifndef MAXFILES
>  73 #define MAXFILES (maxproc * 2)
>  74 #endif
>
> Shouldn't this be at least maxproc*3, for stdin,out,err for every proc?

Even maxproc * 3 won't be enough, unless none of your processes actually
do anything.  It's just an arbitrary value, based on the assumption that
you will never have maxproc concurrent processes anyway.

> Also, it looks like MAXFILES is used only once, and in a bit funny way:
>
> 238         maxfiles =3D MAXFILES;
> 239         TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
> 240         maxprocperuid =3D (maxproc * 9) / 10;
> 241         maxfilesperproc =3D (maxfiles * 9) / 10;

What's funny about it?

> Historical reasons?

To a certain degree, yes; MAXFILES used to be a static limit which you
could only change in your kernel config.  It is now a loader tunable
(though you can still change the default in your kernel config), so the
MAXFILES macro was replaced with a maxfiles variable wherever it is
used, and the former is now only used to initialize the latter.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no