Message-ID: <4014F50E.6020201@cyberone.com.au>
Date: Mon, 26 Jan 2004 22:07:58 +1100
From: Nick Piggin <piggin@cyberone.com.au>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030827 Debian/1.4-3
MIME-Version: 1.0
To: John Levon <levon@movementarian.org>
CC: Andrew Morton <akpm@osdl.org>, Philippe Elie <phil.el@wanadoo.fr>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] oprofile per-cpu buffer overrun
References: <20040126023715.GA3166@zaniah> <20040125200701.3c7b769a.akpm@osdl.org> <20040126103237.GA52771@compsoc.man.ac.uk>
In-Reply-To: <20040126103237.GA52771@compsoc.man.ac.uk>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 991
Lines: 32


John Levon wrote:

>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.
>

You needn't worry about integer overflow - it is handled properly ;)


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/