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 0E0C5C433E0 for ; Mon, 10 Aug 2020 14:53:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C0AE02083B 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" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0AE02083B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 438256B0002; Mon, 10 Aug 2020 10:53:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3E85B6B0003; Mon, 10 Aug 2020 10:53:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2B0F66B0006; Mon, 10 Aug 2020 10:53:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id 16D386B0002 for ; Mon, 10 Aug 2020 10:53:11 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 94FA512F1 for ; Mon, 10 Aug 2020 14:53:10 +0000 (UTC) X-FDA: 77134951740.20.plant21_3f0e97a26fdb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 4D985180C07AB for ; Mon, 10 Aug 2020 14:53:10 +0000 (UTC) X-HE-Tag: plant21_3f0e97a26fdb X-Filterd-Recvd-Size: 4402 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Mon, 10 Aug 2020 14:53:09 +0000 (UTC) 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-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-100-hxj5wZKpOVe85CjiasEM0Q-1; Mon, 10 Aug 2020 10:53:07 -0400 X-MC-Unique: hxj5wZKpOVe85CjiasEM0Q-1 Received: by mail-qv1-f72.google.com with SMTP id j8so7430547qvu.3 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=WnJCgsJuWO+pNhdMq2QSqJ4EfY8ZR3XfzHgRX+2FrECrJH0dNwjBg6r+ddOU7cH+sy 3fIbNeyYRHCBn5M/fPvg4sUkJyAk7rmf0tsRJnHfIXPI3IbOQ9PtysmJbAN7opuq2203 wqzW05qhHO9Gx43ari0wmvVeioRVfIOJnx3Lp4zU22nfy3g3vc9/HhDQKUO4hEbUl1xo AxsiDUCvvFHA2NMYa1Mbm3H41hnQdekjI6OSBNYgaY4csboFxIivckCG+RcCS2G9JKLe wBW2h5mzX9zxANVXFprc+1YipoCM7f7MIDuD6T0FOMo3mz/tikXqUxEO5laAvLGSUX39 6HPA== X-Gm-Message-State: AOAM532nb55Wd1f7d44d9fbKpvRHibA++6UmseWcZPyUtT5wAHbjEzai tCmKYUPJJoELqHw9pYlVOZAG+zKBtVt2VNlnjO3IP+Ae95+evJ35Zm/lyO+C078AsXu0o+rn4TO o2ex7QoilkjI= X-Received: by 2002:a0c:e8c9:: with SMTP id m9mr29209734qvo.178.1597071186713; 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 In-Reply-To: <20200810122419.GA19656@lst.de> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=peterx@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Queue-Id: 4D985180C07AB X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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