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Date: Wed, 26 Mar 2008 10:28:56 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Ingo Molnar <mingo@elte.hu>
CC: Mike Travis <travis@sgi.com>, Andrew Morton <akpm@linux-foundation.org>,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org,
       Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
       Andi Kleen <ak@suse.de>
Subject: Re: [PATCH 06/10] x86: reduce memory and stack usage in	intel_cacheinfo
References: <20080325220650.835342000@polaris-admin.engr.sgi.com> <20080325220651.683748000@polaris-admin.engr.sgi.com> <20080326065023.GG18301@elte.hu> <47EA6EA3.1070609@sgi.com> <20080326171241.GC20016@elte.hu>
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Ingo Molnar wrote:
>> The main goal was to avoid allocating 4096 bytes when only 32 would do 
>> (characters needed to represent nr_cpu_ids cpus instead of NR_CPUS 
>> cpus.) But I'll look at cleaning it up a bit more.  It wouldn't have 
>> to be a function if CHUNKSZ in cpumask_scnprintf() were visible (or a 
>> non-changeable constant.)
> 
> well, do we care about allocating 4096 bytes, as long as we also free 
> it? It's not like we need to clear all the bytes or something. Am i 
> missing something here?

Well, 32 bytes fits on the stack, whereas 4096 bytes requires allocating 
a page -- which means either taking the risk of failing or blocking.  Of 
course, we're doing this for output, which has the same issue.

	-hpa