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 7D7EAC636CC for ; Mon, 13 Feb 2023 16:32:48 +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=Qb9JP823hdGYl9ANoaVR+km395HqPK8w5FHA/GgGoHA=; b=SE6E0ldX2lt0rA+jBd30r0q1ax W3g8GuVrODiovwcxWQp2kfyp28m6HydHkL+9MhBTBxk6xHIznWZXBygUCkzH+Uq72cumF5ZKwcySp zEeqq0IuCTNLUYeSS7acEQp8CoaPnV6Bl4K6eLqbxd9Venz2T+bHxPa74uai0YDlTD4HraxlcqtPg wpsv1bbER2uf643OPR5uqM6rgMggw4jctp4VdZlRTXtj5onMw2M23LlVXPonQDwaJoN2yIQt25D3H HWE5MfF11Fm+j5iCtbPUKYlCGf26rsoe5l5kzCqYGsyjG3ahBwS2bru2Mw1jAFDBhhzWfl79Lwb3j SeVbS1pA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pRbky-00FUXo-NA; Mon, 13 Feb 2023 16:32:44 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pRbkv-00FUVU-1C for linux-nvme@lists.infradead.org; Mon, 13 Feb 2023 16:32:43 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D4B04611B4; Mon, 13 Feb 2023 16:32:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A23DC433D2; Mon, 13 Feb 2023 16:32:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1676305959; bh=jjJDnTGjSXiaZuauJy0MSaY+8liiwCBH6sz7siUAAPk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=El2YPMQdAetDuoea0FE4scf3ht15x3CSpePb62Ly/KCVmi7zLq/ReTZMMlOkOH1+z xOSlnwyeFWl+4A1EYzVxjWcFdx4XN8TNAn+jaWFjKE8xBNRT45SIpGXQpetKAbyIkZ quVDZnsHyH8HM/0jyF7STWQ519WKZdSBLzq7WgTbdhotucZLNIhzDiKK5bl5LmD+IB Ex4h7m84DKxn5NYU6lCkTnZJU7aFVafgMQNx3UE31Wn4PKmM9iWu8fA2GT667GYZLn qP/4wofPMFs3Dlztrh4G03uiG4dJKT2Y5WmNXgE3s2TWSfe4g+Jwnr0/0p95ybgS4i Oz7MjD3K38HkA== Date: Mon, 13 Feb 2023 09:32:35 -0700 From: Keith Busch To: Sagi Grimberg Cc: Christoph Hellwig , Ming Lei , John Meneghini , "linux-nvme@lists.infradead.org" Subject: Re: nvme/pcie hot plug results in /dev name change Message-ID: References: <472fe309-f0f9-65bf-1ad1-8a92a349e973@redhat.com> <2205fb9d-f887-dedc-04c1-06190dc51413@grimberg.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2205fb9d-f887-dedc-04c1-06190dc51413@grimberg.me> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230213_083241_192838_A49C0530 X-CRM114-Status: GOOD ( 19.69 ) 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, Feb 13, 2023 at 04:01:03PM +0200, Sagi Grimberg wrote: > > Also not sure if this is going to work out, but it looks like a good start to > > me. > > > > Instead of user pinning the virtual device so that it never goes away though, I > > considered a user tunable "device missing delay" parameter to debounce link > > events. New IOs would be deferred to the requeue_list while the timer is > > active, and then EIO'ed if the timer expires without a successful LIVE > > controller attachment. The use cases I'm considering are short bounces from > > transient link resets, so I'd expect timers to be from a few seconds to maybe a > > minute. > > Isn't this equivalent to dm-mpath queue_if_no_path or no_path_timeout ? Similiar, but generic to non-multipath devices. > We can keep the mpath device around, but if not, what is the desired > behavior from the upper layers? I don't think we're looking for any behavioral changes in the upper layers.