Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262358AbTHUCYj (ORCPT ); Wed, 20 Aug 2003 22:24:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262361AbTHUCYj (ORCPT ); Wed, 20 Aug 2003 22:24:39 -0400 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:50958 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id S262358AbTHUCYi (ORCPT ); Wed, 20 Aug 2003 22:24:38 -0400 To: linux-kernel@vger.kernel.org From: "H. Peter Anvin" Subject: Re: Interesting VM feature? Date: 20 Aug 2003 19:24:25 -0700 Organization: Transmeta Corporation, Santa Clara CA Message-ID: References: <147bb3140e7a.140e7a147bb3@rdc-kc.rr.com> <20030815200020.GM1027@matchmail.com> <20030815211937.GA20208@mail.jlokier.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Disclaimer: Not speaking for Transmeta in any way, shape, or form. Copyright: Copyright 2003 H. Peter Anvin - All Rights Reserved Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1602 Lines: 43 Followup to: <20030815211937.GA20208@mail.jlokier.co.uk> By author: Jamie Lokier In newsgroup: linux.dev.kernel > > Mike Fedyk wrote: > > On Fri, Aug 15, 2003 at 02:56:02PM -0500, mouschi@wi.rr.com wrote: > > > Is madvise required to result in zero filled pages > > > by a standard, or is this just the commonly accepted > > > behavior? > > > > I believe it is the standard for clean pages, though someone else will have > > to point out where... > > That's the answer to a different question. > > The unanswered question is: what should madvise(MADV_DONTNEED) do, > given dirty pages? > > man madvise(*) says that it zero-fills anonymous private mappings, and > restores private file-backed mappings to the original file pages. > > That is not surprising, as the CPU-friendly semantic is more > complicated to implement, needing an extra flag in the page table > (or rmap structure). > Sounds entirely reasonable. It *would* be nice with a way to be able to say to the kernel "you may discard this but if so I want SIGSEGV", for things like LPSM and the like. -hpa -- at work, in private! If you send me mail in HTML format I will assume it's spam. "Unix gives you enough rope to shoot yourself in the foot." Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64 - 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/