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 CC6CBC624D3 for ; Wed, 2 Sep 2026 13:43:07 +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=4M//c1pxEGkkG7xyiqUFbSWrB4p8VkWOh3hlGp0vRuI=; b=psXVAiOVfh1K1u54jtBw0HNpyI CaM6gb+5uIiiqmYUjC0sTikuK+x74xjRKAiVCST9u6BCEC6AZm9aC6JPpMI8zaCRQ5Np8b8PtLzTm s/NG2LGhEAHJQAWLiIE4L7ysH6UUJxwMuMgvvqpCMX/TXvzoP0l4RmevtEXvzoWvxkL966kaaPDwc 610GRtQ5XvMfnYuVvtk9KfdrOeL+1F++A4zQTAIzuJM/hiXAs8DEVrZhNfCAj50Mm2rFO/4chWCi/ lLXDb9biAzwUp3Xb49X7wnfTJlw7/c0r8GSgMpjcZk0VUfjcyfLN6L4pwm/iDIPmM1Cuvok18nph5 hbVgv7+Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1lF4-0000000Eq04-0awS; Wed, 02 Sep 2026 13:43:06 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1lF1-0000000EpzG-3EBs for linux-nvme@lists.infradead.org; Wed, 02 Sep 2026 13:43:05 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 6982368BEB; Wed, 2 Sep 2026 15:43:00 +0200 (CEST) Date: Wed, 2 Sep 2026 15:43:00 +0200 From: Christoph Hellwig To: Sagi Grimberg Cc: linux-nvme@lists.infradead.org, Christoph Hellwig , Keith Busch , Chaitanya Kulkarni , Daniel Wagner , Shinichiro Kawasaki , Hannes Reinecke Subject: Re: [PATCH 4/6] nvme-mpath: support controller crd when failing over request Message-ID: <20260902134300.GD21649@lst.de> References: <20260823084903.193188-1-sagi@grimberg.me> <20260823084903.193188-5-sagi@grimberg.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260823084903.193188-5-sagi@grimberg.me> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260902_064303_960303_E0EADE67 X-CRM114-Status: GOOD ( 19.15 ) 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 Sun, Aug 23, 2026 at 11:49:00AM +0300, Sagi Grimberg wrote: > When failing over a request (due to a path based status) we should > repect controller crd returned in the nvme completion as much as > possible. Hence we want to delay the failover command execution by > the controller crdt. > > We allocate a new nvme_mpath_failover_timer referencing the request > stolen bios in a staging list, and when the command retry delay expires, > and only then the bios are moved to the mpath head requeue list which is > immediately kicked to re-submit these bios. If we failed to allocate > a fot, we fallback to the existing behavior. > > Given that we now have a new staging list for mpath devices, we drain > them when removing the device. Given that we only have a few potential CRD levels, what about having the "container" for the requing statically preallocated for each?