From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <47EA87D8.8030305@zytor.com> Date: Wed, 26 Mar 2008 10:28:56 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 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> In-Reply-To: <20080326171241.GC20016@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Ingo Molnar Cc: Mike Travis , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Andi Kleen List-ID: 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org