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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 F3471C282CE for ; Mon, 11 Feb 2019 20:40:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8BF12084D for ; Mon, 11 Feb 2019 20:40:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="B1ITolKJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727625AbfBKUkv (ORCPT ); Mon, 11 Feb 2019 15:40:51 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:39038 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727277AbfBKUkv (ORCPT ); Mon, 11 Feb 2019 15:40:51 -0500 Received: by mail-pg1-f193.google.com with SMTP id r11so108013pgp.6 for ; Mon, 11 Feb 2019 12:40:51 -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:user-agent; bh=nmT5nD2I7+KtQoUhHdkWUj1QqpObX7iHadIUM12uKwc=; b=B1ITolKJ1NS4xWfX0ir0qavniH14XixPsbTXipQBHAPuub4IrbOyhFf0bD4uP6LHdP yS1+dqUDzMVRvcvJyextDm7A370NcmuJxo2Gaef7ePt0XpBqOhxFxX2iUaAV1qVgKD0x 8m6rTHR7HFmADoOKyZvx1yyE1yoP+SI6StmEGtj2HeWi9jPom6Dy0b1cc6gXri860E8S kQHnEctpa1aRKDiRprtEqWIL+49NLbsmfIpDYRnY35OR5Uu8inRWQLauyDfY8jHwPyGK jQ5I0OxQrq32U5sCooP0X45Cvj7bJfLsaMeLrt/1ey7bbz7qywYulUwwn2Yi6R+AfX6q 36Uw== 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:user-agent; bh=nmT5nD2I7+KtQoUhHdkWUj1QqpObX7iHadIUM12uKwc=; b=NOtlIRJKlXgDLBmrCqqrgiMsl+j8Lo+07Vpb1BmtlhJ6hJlIaN6eClH1YIexxgiKnR D4v03uSeYnnZBl5zHz5rN/nbzhevpx4UtrVR8tMQEp58FP5MxPcPbCjny93B/82ICPNr WotQvaDv7dm9aUh7h9Llc4J3WDGmSF/y0EZqSTyNLfmhpjuQqMnt9ynSYAaPsD9fetX2 x+TEzZzW3KyrTvOE/bbakHc8mdf/jSN0oi6alVMmAZ3MAyJm9CTgvRjvcmYO85A5iDbP SD0qCETjzg3Qtc+ZMlyWR+skNUca7Zj2nm2sBfzIU0kxpWSG+8Ut+Xw+xTKGTaqJ7GaP FPBw== X-Gm-Message-State: AHQUAuYXQhl+KZYo1Sbd3ICN/kakb+QiU16yBO5d0A1Crk2rvJh2hzfS rJpPBp9fwUy4oLtDV6jpYP8RsQ== X-Google-Smtp-Source: AHgI3IarME8mMwsDqp9azcXs3o7IJfhcXGKpA1KdQX8w0bLUJH9217uYklkSnkg2apnHfTrwcJGclg== X-Received: by 2002:a65:5243:: with SMTP id q3mr66002pgp.385.1549917650694; Mon, 11 Feb 2019 12:40:50 -0800 (PST) Received: from ziepe.ca (S010614cc2056d97f.ed.shawcable.net. [174.3.196.123]) by smtp.gmail.com with ESMTPSA id m67sm19694020pfm.73.2019.02.11.12.40.50 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Feb 2019 12:40:50 -0800 (PST) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1gtINl-0000l1-L6; Mon, 11 Feb 2019 13:40:49 -0700 Date: Mon, 11 Feb 2019 13:40:49 -0700 From: Jason Gunthorpe To: ira.weiny@intel.com Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Daniel Borkmann , Davidlohr Bueso , netdev@vger.kernel.org, Mike Marciniszyn , Dennis Dalessandro , Doug Ledford , Andrew Morton , "Kirill A. Shutemov" , Dan Williams Subject: Re: [PATCH 0/3] Add gup fast + longterm and use it in HFI1 Message-ID: <20190211204049.GB2771@ziepe.ca> References: <20190211201643.7599-1-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211201643.7599-1-ira.weiny@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 11, 2019 at 12:16:40PM -0800, ira.weiny@intel.com wrote: > From: Ira Weiny > > NOTE: This series depends on my clean up patch to remove the write parameter > from gup_fast_permitted()[1] > > HFI1 uses get_user_pages_fast() due to it performance advantages. Like RDMA, > HFI1 pages can be held for a significant time. But get_user_pages_fast() does > not protect against mapping of FS DAX pages. If HFI1 can use the _fast varient, can't all the general RDMA stuff use it too? What is the guidance on when fast vs not fast should be use? Jason