From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 24 Apr 2002 11:31:18 -0700 From: William Lee Irwin III Subject: Re: Why *not* rmap, anyway? Message-ID: <20020424183118.GF26092@holomorphy.com> References: <873cxlunym.fsf@fadata.bg> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline In-Reply-To: <873cxlunym.fsf@fadata.bg> Sender: owner-linux-mm@kvack.org Return-Path: To: Momchil Velikov Cc: Rik van Riel , Christian Smith , Joseph A Knapka , "Martin J. Bligh" , linux-mm@kvack.org List-ID: >>>>> "Rik" == Rik van Riel writes: > Rik> So how do you run a pmap VM without duplicating the data from > Rik> the pmap layer into the page tables ? > Rik> Remember that for VM info the page tables -are- the radix tree. On Wed, Apr 24, 2002 at 06:16:01PM +0300, Momchil Velikov wrote: > And the page tables -are- the pmap layer :) Yes and no; pagetables-as-ADT normally hides the structure and provides a canned set of operations on them. Linux just standardizes the data structure and open-codes access to them in generic code. One could conceive of a pmap/HAT/whatever -like layer that did little more than break off copy_page_range(), zap_page_range(), and a few others into their own file and rename them. At that point it's too minor of a change to warrant actually carrying it through, unless one is particularly concerned about radix tree walking obscuring other operations with actual semantic content. (And it's unclear that it would get very good coverage on that front anyway.) Cheers, Bill -- 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/