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[192.55.52.43]) by mx.google.com with ESMTPS id z3si15010185pgr.90.2019.03.25.15.55.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Mar 2019 15:55:24 -0700 (PDT) Received-SPF: pass (google.com: domain of ira.weiny@intel.com designates 192.55.52.43 as permitted sender) client-ip=192.55.52.43; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ira.weiny@intel.com designates 192.55.52.43 as permitted sender) smtp.mailfrom=ira.weiny@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Mar 2019 15:55:24 -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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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