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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 41166E77199 for ; Tue, 7 Jan 2025 17:13:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tGXF1wB8bCUUJIaQSNFm49+CDkJxWr9k9FYfBPdkhp0=; b=eEFz7fTkxA7NO8Wl6vPCDlv3x8 re+PEBbAKDExTBE7WUSVg639PAHJOAO1BShDl4+5iNsKoz91nnRecEWBm2q/WHN3OJS7waBjJHJVW shcgDwpTt/SLnhtmPsyPYOjfEwf9/EA3pKjxhNpI/NS+H00OR6yQNMle1wJ3PHT6lr2cJOziJuvb4 ruwb1Ys+rCO1SN5/yKxrKLJgX3VHQ34nsvb/gJTvS7DSR5tOU1SIbMvHJQEPmSH7K1Umb7+s4Wiar pYQuyBzu9oIljqUzlTOw+xfpdmn/CULEiRFXz095Nwzrl7HEdzb18FEZLaVKYRVJHh7D2DtCdTpkm HMRwxMdA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tVD98-00000005ncs-3ErD; Tue, 07 Jan 2025 17:13:38 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tVCle-00000005hyZ-1ofv for linux-nvme@lists.infradead.org; Tue, 07 Jan 2025 16:49:23 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id D189A5C45DC; Tue, 7 Jan 2025 16:48:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34ABDC4CEDD; Tue, 7 Jan 2025 16:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736268561; bh=HSi6q34ynOZd3HYBqDj2cs/lz3W1trBdQH/UeX9MPH0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oONQfQz54Y9eMo9SAjDcLG4W/LUsM/iI0VV1wCVuYLO7cEwBwUg7YGnNrOnHzAMQ5 9qF6WNkuzdsB22g0uyfgENfbYxC018qDtHikWDhBMEltN0MTAsvt0Roxbo3pTiezGS 1hfx5Q+tygTUUojLgJCZH2Sac0BZpHWzLwwmc8dneMEDEnDkz/zyzlye2MIkXeTzs5 5db7p9bYjnu0dvU52rOIofTYvJ8u0+jwKATkiKC8Y3RXEkZ2wMsUL7VwHAXm8v2E0u X4/+u3URGyUtgM6IGm3esnmQXTH0QcV8v1i2sRMhcXLYgYs8AYMdBYUh04VOF4hGDA KHyh6CRq1SJWA== Date: Tue, 7 Jan 2025 09:49:19 -0700 From: Keith Busch To: Guixin Liu Cc: Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , linux-nvme@lists.infradead.org Subject: Re: [PATCH v3] nvmet: handle rw's limited retry flag Message-ID: References: <20241209015344.60861-1-kanie@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241209015344.60861-1-kanie@linux.alibaba.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250107_084922_512508_2309C3E0 X-CRM114-Status: GOOD ( 13.25 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Dec 09, 2024 at 09:53:44AM +0800, Guixin Liu wrote: > In some scenarios, some multipath software setup places the > REQ_FAILFAST_DEV flag on I/O to prevent retries and immediately > switch to other paths for issuing I/O commands. This will reflect > on the NVMe read and write commands with the limited retry flag. > > However, the current NVMe target side does not handle the limited > retry flag, and the target's underlying driver still retries the > I/O. This will result in the I/O not being quickly switched to > other paths, ultimately leading to increased I/O latency. > > When the nvme target receive an rw command with limited retry flag, > handle it in block backend by setting the REQ_FAILFAST_DEV flag to > bio. Thanks, applied to nvme-6.14.