Date: Wed, 10 Dec 2008 16:20:41 +0100 From: "Ivan Voras" <ivoras@freebsd.org> To: "Giorgos Keramidas" <keramida@ceid.upatras.gr> Cc: freebsd-hackers@freebsd.org Subject: Re: MAXFILES in subr_param.c Message-ID: <9bbcef730812100720h5b3aab6ek46c4f36c67a37d58@mail.gmail.com> In-Reply-To: <87bpvkdqex.fsf@kobe.laptop> References: <ghjt9l$hg3$1@ger.gmane.org> <863agws2bv.fsf@ds4.des.no> <ghog9e$r4e$1@ger.gmane.org> <87bpvkdqex.fsf@kobe.laptop>
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2008/12/10 Giorgos Keramidas <keramida@ceid.upatras.gr>:
> On Wed, 10 Dec 2008 14:30:24 +0100, Ivan Voras <ivoras@freebsd.org> wrote:
>>>> Also, it looks like MAXFILES is used only once, and in a bit funny way:
>>>>
>>>> 238 maxfiles = MAXFILES;
>>>> 239 TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
>>>> 240 maxprocperuid = (maxproc * 9) / 10;
>>>> 241 maxfilesperproc = (maxfiles * 9) / 10;
>>>
>>> What's funny about it?
>>
>> MAXFILES is a macro used only once, where it resolves to (maxproc*2).
>> It's not technically incorrect, but it looks like it adds noise.
>
> It doesn't add noise :-)
>
> It's arguably a code quality and `documentation' feature. It provides a
> human-readable, useful name to the "magic" value (maxproc * 2). If we
> decide to bump the default to (maxproc * 10) sometime later, we won't
> have to grovel through the entire src/sys/tree and look for maxproc
> instances that need updating.
The macro is defined and used exactly once, in this file. Other files
probably use maxfiles. The problem is - since it's in an #ifdef block
- is it defined anywhere else? A quick grep yields only this:
conf/NOTES:options MAXFILES=999
conf/options:MAXFILES opt_param.h
I don't know how config interacts with the source - does it shadow the
subr_param.c value?
This isn't a very important question as the system demonstratively
works in any case, I see it more as a style curiosity.
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