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=-5.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 3EA1BC43461 for ; Fri, 4 Sep 2020 16:26:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DD4620684 for ; Fri, 4 Sep 2020 16:26:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="B0ajR51h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726005AbgIDQ0S (ORCPT ); Fri, 4 Sep 2020 12:26:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725984AbgIDQ0S (ORCPT ); Fri, 4 Sep 2020 12:26:18 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E3E4C061244 for ; Fri, 4 Sep 2020 09:26:17 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 504DC5FF1; Fri, 4 Sep 2020 12:26:16 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 504DC5FF1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1599236776; bh=JmgpJNw0ml8XLo3w54o/4NPZc5CBdILaLAkLo2y4K10=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=B0ajR51hX5WnrzIjtWK81BnbZ7a/h/9Ia/SWSHZb1vPQEgTXfUAX86eRf2czzh3PT m2TYw8GwXAJXr/iEkhUx8mpqLwKl1DF3ce38ErViHUW25pp3Ws8HEM9Mh2LLSQPUta F5uTZBNL4jql0s51H7pE08N5VSS9pmm2QAth9d8A= Date: Fri, 4 Sep 2020 12:26:16 -0400 From: Bruce Fields To: Chuck Lever Cc: Bruce Fields , Anna Schumaker , Linux NFS Mailing List Subject: Re: [PATCH v4 2/5] NFSD: Add READ_PLUS data support Message-ID: <20200904162616.GB2158@fieldses.org> References: <20200904135259.GB26706@fieldses.org> <00931C34-6C86-46A2-A3B3-9727DA5E739E@oracle.com> <20200904140324.GC26706@fieldses.org> <164C37D9-8044-4CF4-99A1-5FB722A16B8E@oracle.com> <20200904142923.GE26706@fieldses.org> <20200904144932.GA349848@pick.fieldses.org> <45DCF35D-A919-4A99-9B6D-0952ED0A78E5@oracle.com> <20200904152429.GA1738@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Fri, Sep 04, 2020 at 12:17:29PM -0400, Chuck Lever wrote: > > > > On Sep 4, 2020, at 11:24 AM, Bruce Fields wrote: > > > > I'm not seeing the RDMA connection, by the way. SEEK and READ_PLUS > > should work the same over TCP and RDMA. > > The READ_PLUS result is not DDP-eligible because there's no way for > the client to predict in advance whether there will be data (which > can be moved by RDMA), holes or patterns (which cannot), nor how > many of each there might be. > > Therefore I've asked Anna to leave READ_PLUS disabled on RDMA mounts. Oh, of course, makes sense. I think we should leave ourselves the options of handling some of these unlikely corner cases differently in the two cases, but I wouldn't expect that to cause a noticeable difference in any normal use. --b.