Date: Mon, 26 Jan 2004 10:32:37 +0000
From: John Levon <levon@movementarian.org>
To: Andrew Morton <akpm@osdl.org>
Cc: Philippe Elie <phil.el@wanadoo.fr>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] oprofile per-cpu buffer overrun
Message-ID: <20040126103237.GA52771@compsoc.man.ac.uk>
References: <20040126023715.GA3166@zaniah> <20040125200701.3c7b769a.akpm@osdl.org>
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On Sun, Jan 25, 2004 at 08:07:01PM -0800, Andrew Morton wrote:

> When implementing a circular buffer it is better to not constrain the head
> and tail indices - just let them grow and wrap without bound.  You only need
> to bring them in-bounds when you actually use them to index the buffer.

I'm not sure why that's better.

> - head-tail is always the amount of used space, no need to futz around
>   handling the case where one has wrapped and the other hasn't.

I admit I have a hangover, but it seems to me it would actually be more
complicated to make damn sure that the integer overflow case is
definitely handled properly.

I clearly can't write functioning ring buffers :), so I'd prefer it to
stay as simple as possible.

regards,
john
-- 
Khendon's Law:
If the same point is made twice by the same person, the thread is over.
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