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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 8197CC5DF60 for ; Thu, 7 Nov 2019 08:29:00 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2A36A21882 for ; Thu, 7 Nov 2019 08:29:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="KypO2u9q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A36A21882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 477xQ206GbzF6C8 for ; Thu, 7 Nov 2019 19:28:58 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=rppt@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="KypO2u9q"; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 477wx73f3MzF40n for ; Thu, 7 Nov 2019 19:07:22 +1100 (AEDT) Received: from rapoport-lnx (nesher1.haifa.il.ibm.com [195.110.40.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 14F2F2077C; Thu, 7 Nov 2019 08:07:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573114040; bh=Vs0vmuJFZJfCdBWbcef1JshwZZc9l+YrjwUdtsaNu3k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KypO2u9qQZOpCT97PagoJmJ05jNzzAwEOh5TQuJtaHcnw290kuyiCyRgXcpTDgoff yL2r3/5Nv3OxL5iW1vDTUMldS7lvQVWUl8vBPDTErZIqUCYXU5EvD9rUB9CL4lekw9 M70s0IBFr/3wdhsUYXeg/j3kPNjd4MGq8LMTqoAU= Date: Thu, 7 Nov 2019 10:07:07 +0200 From: Mike Rapoport To: John Hubbard Subject: Re: [PATCH v2 05/18] mm/gup: introduce pin_user_pages*() and FOLL_PIN Message-ID: <20191107080706.GB3239@rapoport-lnx> References: <20191103211813.213227-1-jhubbard@nvidia.com> <20191103211813.213227-6-jhubbard@nvidia.com> <20191105131032.GG25005@rapoport-lnx> <9ac948a4-59bf-2427-2007-e460aad2848a@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9ac948a4-59bf-2427-2007-e460aad2848a@nvidia.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Hocko , Jan Kara , kvm@vger.kernel.org, linux-doc@vger.kernel.org, David Airlie , Dave Chinner , dri-devel@lists.freedesktop.org, LKML , linux-mm@kvack.org, Paul Mackerras , linux-kselftest@vger.kernel.org, Ira Weiny , Jonathan Corbet , linux-rdma@vger.kernel.org, Christoph Hellwig , Jason Gunthorpe , Vlastimil Babka , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , linux-media@vger.kernel.org, Shuah Khan , linux-block@vger.kernel.org, =?iso-8859-1?B?Suly9G1l?= Glisse , Al Viro , Dan Williams , Mauro Carvalho Chehab , bpf@vger.kernel.org, Magnus Karlsson , Jens Axboe , netdev@vger.kernel.org, Alex Williamson , Daniel Vetter , linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S . Miller" , Mike Kravetz Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Nov 05, 2019 at 11:00:06AM -0800, John Hubbard wrote: > On 11/5/19 5:10 AM, Mike Rapoport wrote: > ... > >> --- > >> Documentation/vm/index.rst | 1 + > >> Documentation/vm/pin_user_pages.rst | 212 ++++++++++++++++++++++ > > > > I think it belongs to Documentation/core-api. > > Done: > > diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst > index ab0eae1c153a..413f7d7c8642 100644 > --- a/Documentation/core-api/index.rst > +++ b/Documentation/core-api/index.rst > @@ -31,6 +31,7 @@ Core utilities > generic-radix-tree > memory-allocation > mm-api > + pin_user_pages > gfp_mask-from-fs-io > timekeeping > boot-time-mm Thanks! > ... > >> diff --git a/Documentation/vm/pin_user_pages.rst b/Documentation/vm/pin_user_pages.rst > >> new file mode 100644 > >> index 000000000000..3910f49ca98c > >> --- /dev/null > >> +++ b/Documentation/vm/pin_user_pages.rst > >> @@ -0,0 +1,212 @@ > >> +.. SPDX-License-Identifier: GPL-2.0 > >> + > >> +==================================================== > >> +pin_user_pages() and related calls > >> +==================================================== > > > > I know this is too much to ask, but having pin_user_pages() a part of more > > general GUP description would be really great :) > > > > Yes, definitely. But until I saw the reaction to the pin_user_pages() API > family, I didn't want to write too much--it could have all been tossed out > in favor of a whole different API. But now that we've had some initial > reviews, I'm much more confident in being able to write about the larger > API set. > > So yes, I'll put that on my pending list. > > > ... > >> +This document describes the following functions: :: > >> + > >> + pin_user_pages > >> + pin_user_pages_fast > >> + pin_user_pages_remote > >> + > >> + pin_longterm_pages > >> + pin_longterm_pages_fast > >> + pin_longterm_pages_remote > >> + > >> +Basic description of FOLL_PIN > >> +============================= > >> + > >> +A new flag for get_user_pages ("gup") has been added: FOLL_PIN. FOLL_PIN has > > > > Consider reading this after, say, half a year ;-) > > > > OK, OK. I knew when I wrote that that it was not going to stay new forever, but > somehow failed to write the right thing anyway. :) > > Here's a revised set of paragraphs: > > Basic description of FOLL_PIN > ============================= > > FOLL_PIN and FOLL_LONGTERM are flags that can be passed to the get_user_pages*() > ("gup") family of functions. FOLL_PIN has significant interactions and > interdependencies with FOLL_LONGTERM, so both are covered here. > > Both FOLL_PIN and FOLL_LONGTERM are internal to gup, meaning that neither > FOLL_PIN nor FOLL_LONGTERM should not appear at the gup call sites. This allows > the associated wrapper functions (pin_user_pages() and others) to set the > correct combination of these flags, and to check for problems as well. Great, thanks! > thanks, > > John Hubbard > NVIDIA -- Sincerely yours, Mike.