From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 3 May 2002 02:20:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 3 May 2002 02:20:16 -0400 Received: from penguin.e-mind.com ([195.223.140.120]:15906 "EHLO penguin.e-mind.com") by vger.kernel.org with ESMTP id ; Fri, 3 May 2002 02:20:16 -0400 Date: Fri, 3 May 2002 08:20:57 +0200 From: Andrea Arcangeli To: Gerrit Huizenga Cc: "Martin J. Bligh" , Daniel Phillips , Russell King , linux-kernel@vger.kernel.org Subject: Re: Bug: Discontigmem virt_to_page() [Alpha,ARM,Mips64?] Message-ID: <20020503082057.U11414@dualathlon.random> In-Reply-To: <20020502201043.L11414@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.22.1i X-GnuPG-Key-URL: http://e-mind.com/~andrea/aa.gnupg.asc X-PGP-Key-URL: http://e-mind.com/~andrea/aa.asc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 02, 2002 at 12:28:52PM -0700, Gerrit Huizenga wrote: > In message <20020502201043.L11414@dualathlon.random>, > : Andrea Arcangeli writ > es: > > On Thu, May 02, 2002 at 09:58:02AM -0700, Gerrit Huizenga wrote: > > > In message <3971861785.1020330424@[10.10.2.3]>, > : "Martin J. Bligh" writes: > > > > > With numa-q there's a 512M hole in each node IIRC. that's fine > > > > > configuration, similar to the wildfire btw. > > > > > > > > There's 2 different memory models - the NT mode we use currently > > > > is contiguous, the PTX mode is discontiguous. I don't think it's > > > > as simple as a 512Mb fixed size hole, though I'd have to look it > > > > up to be sure. > > > > > > No - it definitely isn't as simple as a 512 MB hole. Depends on how much > > > > I meant that as an example, I recall that was valid config, 512M of ram > > and 512M hole, then next node 512M ram and 512M hole etc... Of course it > > must be possible to vary the mem size if you want more or less ram in > > each node but still it doesn't generate a problematic layout for > > discontigmem (i.e. not 256 discontigous chunks or something of that > > order). > > I *think* the ranges were typically aligned to 4 GB, although with 8 GB > in a single node, I don't remember what the mapping layout looked like. > > Which made everything but node 0 into HIGHMEM. ok. > > With the "flat" addressing mode that Martin has been using (the > dummied down for NT version) everything is squished together. That > makes it a bit harder to do node local data structures, although he > may have enough data from the MPS table to split memory appropriately. sure, the only issue is the API that the hardware provides to advertise the start/end of the memory for each node. It doesn't matter if it's squashed or not as long as you still know the start/end of the phys ram per node. It also won't make any difference with nonlinear or discontigmem because you need to fill the pgdat anyways to enable the numa heuristics (node-affine-allocations being the most sensible etc..). Andrea