Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750910AbWJQNXN (ORCPT ); Tue, 17 Oct 2006 09:23:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750912AbWJQNXN (ORCPT ); Tue, 17 Oct 2006 09:23:13 -0400 Received: from inti.inf.utfsm.cl ([200.1.21.155]:30617 "EHLO inti.inf.utfsm.cl") by vger.kernel.org with ESMTP id S1750910AbWJQNXL (ORCPT ); Tue, 17 Oct 2006 09:23:11 -0400 Message-Id: <200610171058.k9HAwUIo003086@laptop13.inf.utfsm.cl> To: mfbaustx cc: "Oliver Neukum" , linux-kernel@vger.kernel.org Subject: Re: copy_from_user / copy_to_user with no swap space In-Reply-To: Message from mfbaustx of "Mon, 16 Oct 2006 14:47:13 CDT." X-Mailer: MH-E 7.4.2; nmh 1.1; XEmacs 21.5 (beta27) Date: Tue, 17 Oct 2006 07:58:30 -0300 From: "Horst H. von Brand" X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0.2 (inti.inf.utfsm.cl [200.1.21.155]); Tue, 17 Oct 2006 10:22:51 -0300 (CLST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1611 Lines: 36 mfbaustx wrote: > >>> No. Your code may be only partially paged into RAM. > >>> The same can happen for any mmaped data. > That's what I thought I read. But then my question is: with > on-demand paging, is it possible to have two processes partially > paged? Why shouldn't they be? The whole idea is having just /parts/ (hopefully the ones in active use) in memory. > Surely, it MUST be the case that any processes with > overlapping logical address spaces must be paged coherently. I don't know what this is supposed to mean... > So, > while on-demand "paging-in" allows for partial paging of a process, > is it the case that, on a context switch, the user-space PTE's are > completely erased (so that you get page-faults and can then on-demand > page them in...)? Each process has its own page tables, they don't get in each others hair. And the page tables precisely manage making several processes get access to the /same/ logical addresses, but at /different/ physical addresses. -- Dr. Horst H. von Brand User #22616 counter.li.org Departamento de Informatica Fono: +56 32 2654431 Universidad Tecnica Federico Santa Maria +56 32 2654239 Casilla 110-V, Valparaiso, Chile Fax: +56 32 2797513 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/