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Date: Fri, 29 Feb 2008 10:39:18 -0800 (PST)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Michael Kerrisk <michael.kerrisk@googlemail.com>
cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, aaw <aaw@google.com>,
       Andrew Morton <akpm@linux-foundation.org>, carlos@codesourcery.com,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       linux-kernel <linux-kernel@vger.kernel.org>, drepper@redhat.com,
       mtk.manpages@gmail.com, Geoff Clare <gwc@opengroup.org>
Subject: Re: [RFC/PATCH] RLIMIT_ARG_MAX
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On Fri, 29 Feb 2008, Michael Kerrisk wrote:
> 
> My reading of POSIX.1 (and POSIX doesn't seem very explicit on this point), is
> that the limits on argv+environ and on stack are decoupled, since POSIX
> specifies RLIMIT_STACK and sysconf(_SC_ARG_MAX) and doesn't specify any
> relationship between the two.

I agree. And clearly there _are_ relationships and always have been, but 
equally clearly they simply haven't been a big issue in practice, and 
nobody really cares.

Usually, _SC_ARG_MAX is just so much smaller than RLIMIT_STACK that it 
makes no possible difference.  Which I would actually argue we should just 
continue with: just keep _SC_ARG_MAX a smallish, irrelevant constant.

We still have to have the compile-time ARG_MAX constant (as in *real* 
constant - a #define) anyway, for traditional programs, and you might as 
well make sysconf(_SC_ARG_MAX) always just match ARG_MAX.

It's not like there is likely a single user of _SC_ARG_MAX that cares.

			Linus