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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39388C678D4 for ; Thu, 2 Mar 2023 22:00:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 88D5B6B0071; Thu, 2 Mar 2023 17:00:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 83D506B0073; Thu, 2 Mar 2023 17:00:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6DE116B0074; Thu, 2 Mar 2023 17:00:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 5768C6B0071 for ; Thu, 2 Mar 2023 17:00:26 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 2B4E7AB795 for ; Thu, 2 Mar 2023 22:00:26 +0000 (UTC) X-FDA: 80525327652.05.8E440A6 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf19.hostedemail.com (Postfix) with ESMTP id BA1281A001D for ; Thu, 2 Mar 2023 22:00:23 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Z95kFgtd; spf=pass (imf19.hostedemail.com: domain of peterx@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=peterx@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1677794423; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=zpF+61RhbjBED9gh9OlDPVvD+1GeHmY73K8Lmm1HO1w=; b=lw5wMU7SOOMZhoRXRUC2RC/WSOauOQtgQVq1FQLGFV9eS6/Rp728KvclWH8hAdtDJSaCbZ yzUDD4VEZa001gU/nBYlnXR33K1iaHvc+5CGoWsVUjDmuy89kZWpoILtfnYSpm7DFAIpaB QjO41JR7eVFQUGAEwvjS11mAdy67Heg= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Z95kFgtd; spf=pass (imf19.hostedemail.com: domain of peterx@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=peterx@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1677794423; a=rsa-sha256; cv=none; b=3lVdTVUOTK5YXjvAnyPG4fH4Uwg1WwsaG6jr6F15LGwPt7q32pP7gOG36QImezExR2pwxD n/tmwDUxcfhqerzYQQQ49GJm5t+yBraggUW6JE8x/EPagqmnBDi0E7uNa0BPTw4GM+aGmh uNZOK4CXPo0+0YPegVvYO9evNSxnqA0= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677794423; 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=zpF+61RhbjBED9gh9OlDPVvD+1GeHmY73K8Lmm1HO1w=; b=Z95kFgtdGfyhOqfPmAxmrn79PNMq0gCems5a1QG8QMEernV/EsnzJRgaMKiHIy+Qr1+aCb f8h1l+d/MN8gxJg5bORvfeAfVzvwkV6L5v3f+rJ8PWKc6OyBGSiGKNoW151OIpivCH/MfK iWeyQz7fY87neaaEJFhujIZ9Wjw2pyc= Received: from mail-qv1-f71.google.com (mail-qv1-f71.google.com [209.85.219.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-531-TXtJDpXsM2yW0lT8fheTsg-1; Thu, 02 Mar 2023 17:00:21 -0500 X-MC-Unique: TXtJDpXsM2yW0lT8fheTsg-1 Received: by mail-qv1-f71.google.com with SMTP id pv11-20020ad4548b000000b0056e96f4fd64so385933qvb.15 for ; Thu, 02 Mar 2023 14:00:21 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677794420; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=zpF+61RhbjBED9gh9OlDPVvD+1GeHmY73K8Lmm1HO1w=; b=yryAWYG3lAljjyoFzDXklyJjpYuHgL+vccT6By1PnlkPLUOkL6OdxmPs7DZY56U7H2 z/cXwOuhoCpIDaXO3Lg0dwk1yAnuZJxwKYT7ZtVtZh+vIerCx07Y/s5hZ4Yh++E0gbgc WfIHQizCWyv/eW4On4x+PuL6GwiOP/ClfIrmirqj9QKWh0maoD7m9cKtwHJ3jiyDauSI 0bpHjYWHKv05p+Jka7HGh1/30pNXZowVMLCjzpmpekXaz4abNBQXOZQGrdu58eaqM1h6 YpWtS3XeMAsx8V6cdV0h4fOvD6nxC9eDLsDz3urCMAPsNwfFRMUi2cb9MRtq/LGlezWy RUnw== X-Gm-Message-State: AO0yUKXFGAiU7idSRRmqqz8e5pUmukCrnv+HEHckX7c5Aui4BErtFTB1 yYLi9nhhcAUqJxeyd5j2jvN2a29EcP8NO8sHhEt5Vmf/P847xMl1XxuHv2F4KlCUXt1MCvJ1a+Z fD3MYxJZsb8E= X-Received: by 2002:ac8:580f:0:b0:3bf:daa8:cacc with SMTP id g15-20020ac8580f000000b003bfdaa8caccmr22832382qtg.3.1677794420495; Thu, 02 Mar 2023 14:00:20 -0800 (PST) X-Google-Smtp-Source: AK7set+Dd+YGqo/SioYo2gFqWFziGqP77BVBRsHhvTjzMkmzleJIrVboVo66FWVtVnDVZtABxKAS4w== X-Received: by 2002:ac8:580f:0:b0:3bf:daa8:cacc with SMTP id g15-20020ac8580f000000b003bfdaa8caccmr22832326qtg.3.1677794420075; Thu, 02 Mar 2023 14:00:20 -0800 (PST) Received: from x1n (bras-base-aurron9127w-grc-56-70-30-145-63.dsl.bell.ca. [70.30.145.63]) by smtp.gmail.com with ESMTPSA id a191-20020ae9e8c8000000b007423843d879sm427457qkg.93.2023.03.02.14.00.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Mar 2023 14:00:19 -0800 (PST) Date: Thu, 2 Mar 2023 17:00:18 -0500 From: Peter Xu To: Muhammad Usama Anjum Cc: David Hildenbrand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrea Arcangeli , Andrew Morton , Mike Rapoport , Axel Rasmussen , Nadav Amit , "kernel@collabora.com" Subject: Re: [PATCH v2] mm/uffd: UFFD_FEATURE_WP_UNPOPULATED Message-ID: References: <640319be-ddb6-d74f-b731-eee5ceab3d01@collabora.com> <8783f47e-76ea-cd24-e373-f2156884cd05@redhat.com> <982c1623-ac28-2743-d6a3-4faf42f72d47@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: BA1281A001D X-Stat-Signature: 74ccyt6w7j5gyupmc9kefqtjbm9kdg17 X-HE-Tag: 1677794423-121478 X-HE-Meta: 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 DeJDSkr9 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000003, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Mar 02, 2023 at 08:14:05PM +0500, Muhammad Usama Anjum wrote: > I've heard about a use case where a file of size 10s of GBs can be mapped > to the memory and then accessed off and on. We need to handle this > correctly and efficiently. Note again that besides any slowness it'll stop working for generic FSs. One way is we can consider enabling uffd-wp async for all archs, but I need to think more about it, and it will not be compatible with any other modes. -- Peter Xu