From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B66FC433E1 for ; Mon, 10 Aug 2020 14:53:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AD642224D for ; Mon, 10 Aug 2020 14:53:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WbRJEWvy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727077AbgHJOxK (ORCPT ); Mon, 10 Aug 2020 10:53:10 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45974 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726528AbgHJOxK (ORCPT ); Mon, 10 Aug 2020 10:53:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597071188; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Q9TqSnIMVwxHy1nFrUyMg9B9EzCfp0PQ28lqABt/29c=; b=WbRJEWvy6RidJkmhaCJfV65m/mbA5cjJdSGNbqEvw97mau8aSxBzf3t3utMoyPQy55Dp3b ln+fLOCSl2FwY9XAZYev0B46XnvJ2CgMo+1X/BFq2A4LLSzztG2rpqZqEy1lX8zAhI9diX Vsv+SMbkotrs9WZzi+utJGjSR6zCKPk= Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-103-tN_RNI5bP4q3jikMuyMQxA-1; Mon, 10 Aug 2020 10:53:07 -0400 X-MC-Unique: tN_RNI5bP4q3jikMuyMQxA-1 Received: by mail-qt1-f197.google.com with SMTP id b1so7602083qto.17 for ; Mon, 10 Aug 2020 07:53:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Q9TqSnIMVwxHy1nFrUyMg9B9EzCfp0PQ28lqABt/29c=; b=hqc8oIwsoJvgly/WfsLEXDbD0omXGaeNWR36QptYslkuxzzzV42XyUfCpLJybL+h+a KOK77r5Vcf+g3c++zF31anZE6XzsjJG48pDPSWHX8F5cX2pVjodoQkcnV1CpQXvRool4 eczUi025fBAEM9DmD5Yv0t1zxQf/uNTuk+ibQjTacjAWbx5eAp+ZySUQH/YtYHtU1SWS KOfmVUJ1z2EUQfPGPadPwuEHDz92hHdL7TtJJ6Pr2ZGdF1KkmQrtbfOxwFZtp3MyjUwd GW27OPPvebge4MPK2Li4NyusQeg+9hG9I4fldID8BgNKhfOUcNHR614edtKcn3uqoDkd djOA== X-Gm-Message-State: AOAM531OJXoMZqI02tELrctA4wt2+RjlRSdD3ZjGJOVvRja6Zqrfy4hh 4j/qD40m/CSwZ0dnLZZND4GD5UrUCK7ByD3h7PN2b6dcqOTBIO7ys6/xexdHd74QJihzJuHjceG ixSNFfvm9lDYaU9QsYgu/MmNC X-Received: by 2002:a0c:e8c9:: with SMTP id m9mr29209732qvo.178.1597071186712; Mon, 10 Aug 2020 07:53:06 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx35KSUYtVpyur7/ktMciwY/MrlNHdD5p6sLrBAE56nAd6pvBUCzhXIljMTe+dNVHg9NAJ28g== X-Received: by 2002:a0c:e8c9:: with SMTP id m9mr29209706qvo.178.1597071186495; Mon, 10 Aug 2020 07:53:06 -0700 (PDT) Received: from xz-x1 (bras-vprn-toroon474qw-lp130-11-70-53-122-15.dsl.bell.ca. [70.53.122.15]) by smtp.gmail.com with ESMTPSA id y7sm16728866qta.36.2020.08.10.07.53.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Aug 2020 07:53:05 -0700 (PDT) Date: Mon, 10 Aug 2020 10:53:03 -0400 From: Peter Xu To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Marty Mcfadden , Andrea Arcangeli , Linus Torvalds , Jann Horn , Oleg Nesterov , Kirill Shutemov , Jan Kara Subject: Re: [PATCH] mm/gup: Allow real explicit breaking of COW Message-ID: <20200810145303.GA16451@xz-x1> References: <20200808223802.11451-1-peterx@redhat.com> <20200810122419.GA19656@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200810122419.GA19656@lst.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 10, 2020 at 02:24:19PM +0200, Christoph Hellwig wrote: > This patch only seems to add a flag, but no actual user of it. Oops, right.. I'll repost with below squashed into it: diff --git a/mm/gup.c b/mm/gup.c index 6f47697f8fb0..9d1f44b01165 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -870,6 +870,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, return -ENOENT; if (*flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; + if (*flags & FOLL_BREAK_COW) + fault_flags |= FAULT_FLAG_BREAK_COW; if (*flags & FOLL_REMOTE) fault_flags |= FAULT_FLAG_REMOTE; if (locked) Thanks, -- Peter Xu