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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 59AF7C55189 for ; Wed, 22 Apr 2020 08:37:52 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2918E206B9 for ; Wed, 22 Apr 2020 08:37:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lUqU/7fa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2918E206B9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=u4pxJjhE/OvG+Tpta+eQ6MzChK8ymz6u6pQf9YyY3Dw=; b=lUqU/7fadvK6j5 s6X16IYcvoNvl6/Fb/TCA21pChx61oGXnEeqQDoIf6+x/gFcZuo4e6b0vE5zf/Qowrluz2nhjkmoS KEs6yYQpXtMiyL6/dwx//hGHyBk5ZN3O1gQaSWPugUbvOoSfJZWRVkd0mKMAwrNGfr7QCFTtZRXjv 9e74DfJWpK2/9cRirrTKkVs+L/W2y8Rr7DKxPNA5X8q3nPrBtb0FVUj6/BMcpeaAlantmUSidIV1w 5TpX5JstNS+DhZo43qZvh3c5c/cFheHLgUZauGGq5eLDME1q46nlrevhpiv9ux+MPUpCNVAmeLqzX IR01Hh/vxXBR3aE86fcQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRAtC-00023C-32; Wed, 22 Apr 2020 08:37:50 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRAt9-00021t-O4; Wed, 22 Apr 2020 08:37:47 +0000 Date: Wed, 22 Apr 2020 01:37:47 -0700 From: Christoph Hellwig To: Max Gurtovoy Subject: Re: [PATCH] nvme: align io queue count with allocted nvme_queue in nvme_probe Message-ID: <20200422083747.GA26915@infradead.org> References: <20200410095719.GA4393@192.168.3.9> <188ad279-9211-9dca-3e6c-b5718ae6fc80@mellanox.com> <66add5c2-62b9-5c2d-977b-0499834b2b7a@mellanox.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Weiping Zhang , Weiping Zhang , linux-nvme@lists.infradead.org, Christoph Hellwig , Keith Busch , sagi@grimberg.me Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Apr 14, 2020 at 03:59:12PM +0300, Max Gurtovoy wrote: > > > write_queues and poll queues shouldn't be writable IMO. > > > > > I think we can keep it writeable, the user case is that setup as many io > > queues as possible when load nvme module, then change queue count > > for each tag set map dynamically. > > We can keep it writable but I prefer not change the controller initial queue > count after reset controller operation. > > So we can keep dev->write_queues and dev->poll_queues count for that. > > You can use the writable param in case you aim to hotplug a new device and > you want it to probe with less/more queues. > > IMO this feature should've somehow configured using nvme-cli as we do with > fabrics controllers that we never change this values after initial > connection. > > Keith/Christoph, > > what is the right approach in your opinion ? The problem with PCIe is that we only have a per-controller interface once the controller is probed. So a global paramter that can be changed, but only is sampled once at probe time seems the easiest to me. We could also allow a per-controller sysfs file that only takes effect after a reset, which seems a little nicer, but adds a lot of boilerplate for just being a little nicer, so I'm not entirely sure if it is worth the effort. _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme