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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 94C50C433ED for ; Mon, 26 Apr 2021 14:43:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5907361164 for ; Mon, 26 Apr 2021 14:43:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233923AbhDZOoB (ORCPT ); Mon, 26 Apr 2021 10:44:01 -0400 Received: from verein.lst.de ([213.95.11.211]:41591 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233501AbhDZOoA (ORCPT ); Mon, 26 Apr 2021 10:44:00 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 2752468C4E; Mon, 26 Apr 2021 16:43:17 +0200 (CEST) Date: Mon, 26 Apr 2021 16:43:16 +0200 From: Christoph Hellwig To: Keith Busch Cc: linux-nvme@lists.infradead.org, sagi@grimberg.me, hch@lst.de, axboe@kernel.dk, linux-block@vger.kernel.org, Yuanyuan Zhong , Casey Chen Subject: Re: [PATCHv2 5/5] nvme: allow user passthrough commands to poll Message-ID: <20210426144316.GE20668@lst.de> References: <20210423220558.40764-1-kbusch@kernel.org> <20210423220558.40764-6-kbusch@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210423220558.40764-6-kbusch@kernel.org> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Apr 23, 2021 at 03:05:58PM -0700, Keith Busch wrote: > The block layer knows how to deal with polled requests. Let the NVMe > driver use the previously reserved user "flags" fields to define an > option to allocate the request from the polled hardware contexts. If > polling is not enabled, then the block layer will automatically fallback > to a non-polled request. So this only support synchronous polling for a single command. What use case do we have for that? I think io_uring based polling would be much more useful once we support NVMe passthrough through that.