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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 D8CB6C433E0 for ; Mon, 11 Jan 2021 16:06:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B10D21D7F for ; Mon, 11 Jan 2021 16:06:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388353AbhAKQGc (ORCPT ); Mon, 11 Jan 2021 11:06:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727180AbhAKQGb (ORCPT ); Mon, 11 Jan 2021 11:06:31 -0500 Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11903C061786 for ; Mon, 11 Jan 2021 08:05:51 -0800 (PST) Received: by mail-qt1-x831.google.com with SMTP id y15so21366qtv.5 for ; Mon, 11 Jan 2021 08:05:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=VJXKJfI0gkDENX20LedauSobFPKF2L5M/RH/WmsJp4Q=; b=QjUyGJ59RkTenwFcqXVFU8Zcc3L7HYBxKmb4Tk+6nNJKizrbrrTv6nJblC/YT3Vdpn BKl24NzdGALlS4FrA+pAi4StCQE3H94rtiZnxwjEkj4nekVK9TwCD8bfI7Cx8AS6/QK9 hwTjB75PvTQJZ4goicxxTHAp9voTWbGLOzdnuojAujabAppnuE8eUOWYPBRz6+T0L1UT HrVRuTgmtFbCdCgQ3ntXgEKgziYpheEhknBrRGrzns9XUrOSvTPD39aqtU8l3GmBS0EA COhGArctwrcxAjKs68+aSTkfcIl1a4/s3Txd9Qjs7XvS21C/79GpUDnAQ1OwTaXQs7gG XKmQ== 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=VJXKJfI0gkDENX20LedauSobFPKF2L5M/RH/WmsJp4Q=; b=WO618aDDo/3A4KEgaICudISClt0XyC9xKjZU/5lD2mLwvkO1++JkhrsSHGBNXQx4VW Chjo69CcRDxO2r6Z4006QO9YOM/eGo7KWTMz3giTNL0XC1Wk037bXHH7jpE62UFRFx65 igiDkrBBgdxaUJhVVop75Gi20kBB4vZet3F7n4QbTaJDMZx3YE9OV7KpHOEIRM7p7MXC 4ldrp2BQUPWULZntTP4wCIjbt3PlBHrt1z+CYHAC7yo77JSa4KGNXzQ9uDqcBrZyIOW8 pyGjychBGR3pyzjgk6gXHtpryAkVa76cAhWi3k/3Ol3viovDcC/6ze03Jzy7PkdHKJAX dn4Q== X-Gm-Message-State: AOAM5335eDiC80oUclUSyhtwSS4JhvozvyitRiiRR+L+3ZJ1IWeViVxQ yqfB6WHoYjoZhNESapgG36Lmcw== X-Google-Smtp-Source: ABdhPJxKir1OyQ6oe0SGLvUrpJGUR7oMsv4PsZ0mfg/4Ho7fV9G2CV+kpE259jU4OUWjCpYN/9BrOw== X-Received: by 2002:ac8:4c8c:: with SMTP id j12mr268786qtv.133.1610381150214; Mon, 11 Jan 2021 08:05:50 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-115-133.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.115.133]) by smtp.gmail.com with ESMTPSA id h75sm91222qke.130.2021.01.11.08.05.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Jan 2021 08:05:49 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kyzhV-005YPG-0o; Mon, 11 Jan 2021 12:05:49 -0400 Date: Mon, 11 Jan 2021 12:05:49 -0400 From: Jason Gunthorpe To: John Hubbard Cc: Linus Torvalds , Andrea Arcangeli , Andrew Morton , Linux-MM , Linux Kernel Mailing List , Yu Zhao , Andy Lutomirski , Peter Xu , Pavel Emelyanov , Mike Kravetz , Mike Rapoport , Minchan Kim , Will Deacon , Peter Zijlstra , Hugh Dickins , "Kirill A. Shutemov" , Matthew Wilcox , Oleg Nesterov , Jann Horn , Kees Cook , Leon Romanovsky , Jan Kara , Kirill Tkhai , Nadav Amit , Jens Axboe Subject: Re: [PATCH 0/1] mm: restore full accuracy in COW page reuse Message-ID: <20210111160549.GN504133@ziepe.ca> References: <20210110004435.26382-1-aarcange@redhat.com> <45806a5a-65c2-67ce-fc92-dc8c2144d766@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45806a5a-65c2-67ce-fc92-dc8c2144d766@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 10, 2021 at 11:26:57PM -0800, John Hubbard wrote: > So: > > FOLL_PIN: would use DMA_PIN_COUNTING_BIAS to increment page refcount. > These are long term pins for dma. > > FOLL_GET: would use GUP_PIN_COUNTING_BIAS to increment page refcount. > These are not long term pins. Do we have any places yet that care about the long-term-ness? The only place long term would matter is if something is waiting for the page ref count to drop. Jason