Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932079AbaJGRPs (ORCPT ); Tue, 7 Oct 2014 13:15:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41917 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753459AbaJGRPp (ORCPT ); Tue, 7 Oct 2014 13:15:45 -0400 Message-ID: <54341F77.6060400@redhat.com> Date: Tue, 07 Oct 2014 19:14:31 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: "Dr. David Alan Gilbert" , Linus Torvalds CC: Andrea Arcangeli , qemu-devel@nongnu.org, KVM list , Linux Kernel Mailing List , linux-mm , Linux API , Andres Lagar-Cavilla , Dave Hansen , Rik van Riel , Mel Gorman , Andy Lutomirski , Andrew Morton , Sasha Levin , Hugh Dickins , Peter Feiner , Christopher Covington , Johannes Weiner , Android Kernel Team , Robert Love , Dmitry Adamushko , Neil Brown , Mike Hommey , Taras Glek , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , Minchan Kim , Keith Packard , "Huangpeng (Peter)" , Isaku Yamahata , Anthony Liguori , Stefan Hajnoczi , Wenchao Xia , Andrew Jones , Juan Quintela Subject: Re: [PATCH 10/17] mm: rmap preparation for remap_anon_pages References: <1412356087-16115-1-git-send-email-aarcange@redhat.com> <1412356087-16115-11-git-send-email-aarcange@redhat.com> <20141006085540.GD2336@work-vm> <20141006164156.GA31075@redhat.com> <20141007170731.GO2404@work-vm> In-Reply-To: <20141007170731.GO2404@work-vm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 07/10/2014 19:07, Dr. David Alan Gilbert ha scritto: >> > >> > So I'd *much* rather have a "write()" style interface (ie _copying_ >> > bytes from user space into a newly allocated page that gets mapped) >> > than a "remap page" style interface > Something like that might work for the postcopy case; it doesn't work > for some of the other uses that need to stop a page being changed by the > guest, but then need to somehow get a copy of that page internally to QEMU, > and perhaps provide it back later. I cannot parse this. Which uses do you have in mind? Is it for QEMU-specific or is it for other applications of userfaults? As long as the page is atomically mapped, I'm not sure what the difference from remap_anon_pages are (as far as the destination page is concerned). Are you thinking of having userfaults enabled on the source as well? Paolo > remap_anon_pages worked for those cases > as well; I can't think of another current way of doing it in userspace. -- 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/