From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751719AbbJLPET (ORCPT ); Mon, 12 Oct 2015 11:04:19 -0400 Received: from mail-yk0-f179.google.com ([209.85.160.179]:33239 "EHLO mail-yk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751614AbbJLPEM (ORCPT ); Mon, 12 Oct 2015 11:04:12 -0400 MIME-Version: 1.0 In-Reply-To: <1434388931-24487-1-git-send-email-aarcange@redhat.com> References: <1434388931-24487-1-git-send-email-aarcange@redhat.com> Date: Mon, 12 Oct 2015 11:04:11 -0400 Message-ID: Subject: Re: [PATCH 0/7] userfault21 update From: Patrick Donnelly To: Andrea Arcangeli Cc: Andrew Morton , open list , linux-mm@kvack.org, qemu-devel@nongnu.org, kvm@vger.kernel.org, Pavel Emelyanov , Sanidhya Kashyap , zhang.zhanghailiang@huawei.com, Linus Torvalds , "Kirill A. Shutemov" , Andres Lagar-Cavilla , Dave Hansen , Paolo Bonzini , Rik van Riel , Mel Gorman , Andy Lutomirski , Hugh Dickins , Peter Feiner , "Dr. David Alan Gilbert" , Johannes Weiner , "Huangpeng (Peter)" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Andrea, On Mon, Jun 15, 2015 at 1:22 PM, Andrea Arcangeli wrote: > This is an incremental update to the userfaultfd code in -mm. Sorry I'm late to this party. I'm curious how a ptrace monitor might use a userfaultfd to handle faults in all of its tracees. Is this possible without having each (newly forked) tracee "cooperate" by creating a userfaultfd and passing that to the tracer? Have you considered using one userfaultfd for an entire tree of processes (signaled through a flag)? Would not a process id included in the include/uapi/linux/userfaultfd.h:struct uffd_msg be sufficient to disambiguate faults? -- Patrick Donnelly From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick Donnelly Subject: Re: [PATCH 0/7] userfault21 update Date: Mon, 12 Oct 2015 11:04:11 -0400 Message-ID: References: <1434388931-24487-1-git-send-email-aarcange@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Andrew Morton , open list , linux-mm@kvack.org, qemu-devel@nongnu.org, kvm@vger.kernel.org, Pavel Emelyanov , Sanidhya Kashyap , zhang.zhanghailiang@huawei.com, Linus Torvalds , "Kirill A. Shutemov" , Andres Lagar-Cavilla , Dave Hansen , Paolo Bonzini , Rik van Riel , Mel Gorman , Andy Lutomirski , Hugh Dickins , Peter Feiner , "Dr. David Alan Gilbert" , Johannes Weiner , "Huangpeng (Peter)" To: Andrea Arcangeli Return-path: In-Reply-To: <1434388931-24487-1-git-send-email-aarcange@redhat.com> Sender: owner-linux-mm@kvack.org List-Id: kvm.vger.kernel.org Hello Andrea, On Mon, Jun 15, 2015 at 1:22 PM, Andrea Arcangeli wrote: > This is an incremental update to the userfaultfd code in -mm. Sorry I'm late to this party. I'm curious how a ptrace monitor might use a userfaultfd to handle faults in all of its tracees. Is this possible without having each (newly forked) tracee "cooperate" by creating a userfaultfd and passing that to the tracer? Have you considered using one userfaultfd for an entire tree of processes (signaled through a flag)? Would not a process id included in the include/uapi/linux/userfaultfd.h:struct uffd_msg be sufficient to disambiguate faults? -- Patrick Donnelly -- 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: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47452) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zlee8-0007PH-Qt for qemu-devel@nongnu.org; Mon, 12 Oct 2015 11:04:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zlee4-0000JZ-N0 for qemu-devel@nongnu.org; Mon, 12 Oct 2015 11:04:16 -0400 Received: from mail-yk0-f169.google.com ([209.85.160.169]:35201) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zlee4-0000JS-Jy for qemu-devel@nongnu.org; Mon, 12 Oct 2015 11:04:12 -0400 Received: by ykec126 with SMTP id c126so99353232yke.2 for ; Mon, 12 Oct 2015 08:04:11 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1434388931-24487-1-git-send-email-aarcange@redhat.com> References: <1434388931-24487-1-git-send-email-aarcange@redhat.com> Date: Mon, 12 Oct 2015 11:04:11 -0400 Message-ID: From: Patrick Donnelly Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH 0/7] userfault21 update List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrea Arcangeli Cc: "Huangpeng (Peter)" , zhang.zhanghailiang@huawei.com, kvm@vger.kernel.org, Pavel Emelyanov , Hugh Dickins , Johannes Weiner , Dave Hansen , open list , qemu-devel@nongnu.org, linux-mm@kvack.org, Andres Lagar-Cavilla , Mel Gorman , Paolo Bonzini , "Kirill A. Shutemov" , Andrew Morton , Sanidhya Kashyap , Linus Torvalds , Andy Lutomirski , "Dr. David Alan Gilbert" , Peter Feiner Hello Andrea, On Mon, Jun 15, 2015 at 1:22 PM, Andrea Arcangeli wrote: > This is an incremental update to the userfaultfd code in -mm. Sorry I'm late to this party. I'm curious how a ptrace monitor might use a userfaultfd to handle faults in all of its tracees. Is this possible without having each (newly forked) tracee "cooperate" by creating a userfaultfd and passing that to the tracer? Have you considered using one userfaultfd for an entire tree of processes (signaled through a flag)? Would not a process id included in the include/uapi/linux/userfaultfd.h:struct uffd_msg be sufficient to disambiguate faults? -- Patrick Donnelly