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 A007AC10F03 for ; Mon, 25 Mar 2019 22:55:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 772FE206C0 for ; Mon, 25 Mar 2019 22:55:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730657AbfCYWz0 (ORCPT ); Mon, 25 Mar 2019 18:55:26 -0400 Received: from mga18.intel.com ([134.134.136.126]:9258 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729204AbfCYWzY (ORCPT ); Mon, 25 Mar 2019 18:55:24 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.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 Cc: Jason Gunthorpe , Andrew Morton , John Hubbard , Michal Hocko , "Kirill A. Shutemov" , Peter Zijlstra , Benjamin Herrenschmidt , Paul Mackerras , "David S. Miller" , Martin Schwidefsky , Heiko Carstens , Rich Felker , Yoshinori Sato , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Ralf Baechle , James Hogan , linux-mm , Linux Kernel Mailing List , linux-mips@vger.kernel.org, linuxppc-dev , linux-s390 , Linux-sh , sparclinux@vger.kernel.org, linux-rdma , "netdev@vger.kernel.org" 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) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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