From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sd0109e.au.ibm.com (d23rh905.au.ibm.com [202.81.18.225]) by e23smtp05.au.ibm.com (8.13.1/8.13.1) with ESMTP id m1L5pOi0015743 for ; Thu, 21 Feb 2008 16:51:24 +1100 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by sd0109e.au.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m1L5tGYk264418 for ; Thu, 21 Feb 2008 16:55:16 +1100 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m1L5pbe7017389 for ; Thu, 21 Feb 2008 16:51:38 +1100 Message-ID: <47BD1052.2090204@linux.vnet.ibm.com> Date: Thu, 21 Feb 2008 11:16:58 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com MIME-Version: 1.0 Subject: Re: [PATCH] Document huge memory/cache overhead of memory controller in Kconfig References: <20080220122338.GA4352@basil.nowhere.org> <200802211535.38932.nickpiggin@yahoo.com.au> <47BD06C2.5030602@linux.vnet.ibm.com> <200802211622.51751.nickpiggin@yahoo.com.au> In-Reply-To: <200802211622.51751.nickpiggin@yahoo.com.au> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andi Kleen , akpm@osdl.org, torvalds@osdl.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Nick Piggin wrote: >> 1. We could create something similar to mem_map, we would need to handle 4 > >> different ways of creating mem_map. > >> 2. On x86 with 64 GB ram, if we decided to use vmalloc space, we would need > >> 64 MB of vmalloc'ed memory > > That's going to be a big job. You could probably do it quite easily for > > flatmem (just store an offset into the start of your page array), and > > maybe even sparsemem (add some "extra" information to the extents). > >> I have not explored your latest suggestion of pfn <-> memory controller > >> mapping yet. I'll explore it and see how that goes. > > If you did that using a radix-tree, then it could be a runtime option > > without having to use vmalloc. And you wouldn't have to care about > > memory models. I'd say it will be the fastest way to get a prototype > > running. > OK, I'll explore and prototype the radix tree based approach and see how that goes. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL -- 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