From: ebiederm@xmission.com (Eric W. Biederman)
To: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
       "Protasevich, Natalie" <Natalie.Protasevich@unisys.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86_64: Make NR_IRQS configurable in Kconfig
References: <m1irl4ftya.fsf@ebiederm.dsl.xmission.com>
	<200608071733.13562.ak@suse.de>
Date: Mon, 07 Aug 2006 09:55:09 -0600
In-Reply-To: <200608071733.13562.ak@suse.de> (Andi Kleen's message of "Mon, 7
	Aug 2006 17:33:13 +0200")
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Andi Kleen <ak@suse.de> writes:

> On Monday 07 August 2006 17:26, Eric W. Biederman wrote:
>> 
>> Currrently on a SMP system we can theoretically support
>> NR_CPUS*224 irqs.  Unfortunately our data structures
>> don't cope will with that many irqs, nor does hardware
>> typically provide that many irq sources.
>> 
>> With the number of cores starting to follow Moores
>> law, and the apicid limits being raised beyond an 8bit
>> number trying to track our current maximum with our
>> current data structures would be fatal and wasteful.
>> 
>> So this patch decouples the number of irqs we support
>> from the number of cpus.  We can revisit this decision
>> once someone reworks the current data structures.
>
> Ok. I was about to apply it, but it seems to require
> mm patches right now, so i didn't

Right.  This is post 2.6.18 material, that is getting
the final bug fixes now.  So it will be ready when 2.6.19 opens
up.  Andi I just wanted to make certain you saw it. :)

Eric
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