linux-kernel - Re: [PATCH 4/5] Add a sysconf syscall

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Message-ID: <20110516160114.GA25898@one.firstfloor.org>
Date:	Mon, 16 May 2011 18:01:14 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Denys Vlasenko <vda.linux@...glemail.com>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	libc-alpha@...rceware.org, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 4/5] Add a sysconf syscall

> ...and libc will start making many such calls in a row in order to retrieve
> a dozen of such values.

It doesn't because the user interface is sysconf(). So the user program
just asks for it piece by piece.

> It's rather inefficient to return just one word.
> Try to return more data per call.

I considered that, but is there a concrete use case?
I didn't want to code it up without concrete use case.

> Pass a pointer to the result struct and its length.
> Future-proof API, such as using generously wide data types,
> passing "version of struct" input parameter to facilitate incompatible
> future changes, etc.

Please provide a use case for all this complexity.

[... more complexity snipped ... ]

-Andi
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