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=-2.5 required=3.0 tests=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 8CD5AC04EBC for ; Fri, 16 Nov 2018 09:49:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 62EC52086C for ; Fri, 16 Nov 2018 09:49:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62EC52086C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389424AbeKPUBY (ORCPT ); Fri, 16 Nov 2018 15:01:24 -0500 Received: from verein.lst.de ([213.95.11.211]:48408 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727442AbeKPUBY (ORCPT ); Fri, 16 Nov 2018 15:01:24 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id E3C6B68D60; Fri, 16 Nov 2018 10:49:47 +0100 (CET) Date: Fri, 16 Nov 2018 10:49:47 +0100 From: Christoph Hellwig To: Hannes Reinecke Cc: Christoph Hellwig , Mike Snitzer , linux-nvme@lists.infradead.org, Keith Busch , Sagi Grimberg , axboe@kernel.dk, Martin Wilck , lijie , xose.vazquez@gmail.com, chengjike.cheng@huawei.com, shenhong09@huawei.com, dm-devel@redhat.com, wangzhoumengjian@huawei.com, christophe.varoqui@opensvc.com, bmarzins@redhat.com, sschremm@netapp.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] nvme: allow ANA support to be independent of native multipathing Message-ID: <20181116094947.GA19296@lst.de> References: <20181112215323.GA7983@redhat.com> <20181113161838.GC9827@localhost.localdomain> <20181113180008.GA12513@redhat.com> <20181114053837.GA15086@redhat.com> <30cf7af7-8826-55bd-e39a-4f81ed032f6d@suse.de> <20181114174746.GA18526@redhat.com> <87c931e5-4ac9-1795-8d40-cc5541d3ebcf@suse.de> <20181115174605.GA19782@redhat.com> <20181116091458.GA17267@lst.de> <37098edd-4dea-b58f-bca6-3be9af8ec4ee@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <37098edd-4dea-b58f-bca6-3be9af8ec4ee@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 16, 2018 at 10:40:40AM +0100, Hannes Reinecke wrote: >>> Introduce ability to always re-read ANA log page as required due to ANA >>> error and make current ANA state available via sysfs -- even if native >>> multipathing is disabled on the host (e.g. nvme_core.multipath=N). >> >> The first part I could see, but I still want to make it conditional >> in some way as nvme is going into deeply embedded setups, and I don't >> want to carry the weight of the ANA code around for everyone. >> > Can you clarify this a bit? > We _do_ have the NVME multipath config option to deconfigure the whole > thing during compile time; that isn't influenced with this patch. > So are you worried about the size of the ANA implementation itself? > Or are you worried about the size of the ANA structures? I just see the next step of wanting to move ANA code into the core which is implied above. > >> The second I fundamentally disagree with. And even if you found agreement >> it would have to be in a separate patch as it is a separate feature. >> > Why? Where's the problem with re-reading the ANA log pages if we get an > event indicating that we should? "second" here means the sysfs file.