From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <417EC3E9.5020406@kolumbus.fi> Date: Wed, 27 Oct 2004 00:38:49 +0300 From: =?ISO-8859-1?Q?Mika_Penttil=E4?= MIME-Version: 1.0 Subject: Re: [Lhms-devel] Re: 150 nonlinear References: <1098815779.4861.26.camel@localhost> <417EA06B.5040609@kolumbus.fi> <1098819748.5633.0.camel@localhost> <417EB684.1060100@kolumbus.fi> <1098824141.6188.1.camel@localhost> <417EBFB3.5000803@kolumbus.fi> <1098826023.7172.4.camel@localhost> In-Reply-To: <1098826023.7172.4.camel@localhost> Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: Andy Whitcroft , lhms , linux-mm List-ID: Dave Hansen wrote: >On Tue, 2004-10-26 at 14:20, Mika Penttila wrote: > > >>"There are two problems that are being solved: having a sparse layout >>requiring splitting up mem_map (solved by discontigmem and your >>nonlinear), and supporting non-linear phys to virt relationships (Dave >>M's implentation which does the mem_map split as well)." >> >> >>so what's the split? >> >> > >So, mem_map is normally laid out so that, if you have 1GB of memory, the >memory for 0x00000000 is at mem_map[0], and the memory for the last page >(at 1GB - 1 page) is at mem_map[1<<30 / PAGE_SIZE - 1]. > >That's fine and dandy for most systems. But, imagine that you have some >memory on a funky machine where you have 2GB of memory, but it is laid >out like this: > > 0-1 GB - first 1 GB > 1-100 GB - empty >100-101 GB - second 1 GB > >Then, you'd need to have mem_map sized the same as a 101GB system on >your dinky 2GB system (disregard the ia64 implementation). > >The split I'm referring to is cutting mem_map[] up into pieces for each >contiguous section of memory. > >Make sense? > >-- Dave > > > > Yes, I see Dave M's approarch is doing this, but isn't Andy's as well? What's the key differences between these two? --Mika -- 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: aart@kvack.org