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=-1.4 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 91F16C43381 for ; Mon, 25 Mar 2019 22:57:14 +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 D577020828 for ; Mon, 25 Mar 2019 22:57:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D577020828 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44SqQb2yKRzDqMF for ; Tue, 26 Mar 2019 09:57:11 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=intel.com (client-ip=134.134.136.24; helo=mga09.intel.com; envelope-from=ira.weiny@intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=intel.com Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (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 44SqNl5YR8zDqKr for ; Tue, 26 Mar 2019 09:55:27 +1100 (AEDT) X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Mar 2019 15:55:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,270,1549958400"; d="scan'208";a="137221326" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga003.jf.intel.com with ESMTP; 25 Mar 2019 15:55:22 -0700 Date: Mon, 25 Mar 2019 07:54:11 -0700 From: Ira Weiny To: Dan Williams Subject: Re: [RESEND 4/7] mm/gup: Add FOLL_LONGTERM capability to GUP fast Message-ID: <20190325145411.GI16366@iweiny-DESK2.sc.intel.com> References: <20190317183438.2057-1-ira.weiny@intel.com> <20190317183438.2057-5-ira.weiny@intel.com> <20190325084225.GC16366@iweiny-DESK2.sc.intel.com> <20190325164713.GC9949@ziepe.ca> <20190325092314.GF16366@iweiny-DESK2.sc.intel.com> <20190325175150.GA21008@ziepe.ca> <20190325142125.GH16366@iweiny-DESK2.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.1 (2018-12-01) 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 , Linux-sh , Peter Zijlstra , James Hogan , Heiko Carstens , linux-mips@vger.kernel.org, linux-mm , Rich Felker , Paul Mackerras , sparclinux@vger.kernel.org, linux-s390 , Yoshinori Sato , linux-rdma , Jason Gunthorpe , Ingo Molnar , John Hubbard , Borislav Petkov , Thomas Gleixner , "netdev@vger.kernel.org" , Linux Kernel Mailing List , Ralf Baechle , Martin Schwidefsky , Andrew Morton , linuxppc-dev , "David S. Miller" , "Kirill A. Shutemov" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Mar 25, 2019 at 03:36:28PM -0700, Dan Williams wrote: > On Mon, Mar 25, 2019 at 3:22 PM Ira Weiny wrote: > [..] > > FWIW this thread is making me think my original patch which simply implemented > > get_user_pages_fast_longterm() would be more clear. There is some evidence > > that the GUP API was trending that way (see get_user_pages_remote). That seems > > wrong but I don't know how to ensure users don't specify the wrong flag. > > What about just making the existing get_user_pages_longterm() have a > fast path option? That would work but was not the direction we agreed upon before.[1] At this point I would rather see this patch set applied, focus on fixing the filesystem issues, and once that is done determine if FOLL_LONGTERM is needed in any GUP calls. Ira [1] https://lkml.org/lkml/2019/2/11/2038