From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E20312FD665 for ; Tue, 10 Feb 2026 15:41:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770738073; cv=none; b=L6iEY/zJ9p1Lhs1hqXoFbeoTFUjllghFcbCI9JUA5G1Ye6MSIVKiGPA9QXCB2VdChIgt8jkBlTqoXdAcUtn3tvrlJjf9aIBOjjyUf4Q1W7uqsjY7YZlGvXlSvXEjSUQ+l8+lU3Fn27QJ6OTr2t3ERRaxsDMzzJVsT12FI9G7HnU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770738073; c=relaxed/simple; bh=8piujjumgiPklCiYYgLaRuhHH7eiq9oHd/YV6rmAyQQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ItUvemuSEAQOxFZ9K/vvcf1Pzpwo2dOesyvA4T07uEdKuUTVyUGKx05NW6Psq9FBrnc3jjkOqbYqIWO7eXot4IYiFIKXelxFMio8CpZTlwmVqjmnKmEfGJTmXmT3UdZB9SOhPxQRhorMQhS/bOdLbaN4bDr63wMSl6pAM0V28Bs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 2779868CFE; Tue, 10 Feb 2026 16:41:09 +0100 (CET) Date: Tue, 10 Feb 2026 16:41:08 +0100 From: Christoph Hellwig To: Keith Busch Cc: Yu Kuai , Christoph Hellwig , axboe@kernel.dk, sagi@grimberg.me, sven@kernel.org, j@jannau.net, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, tj@kernel.org, nilay@linux.ibm.com, ming.lei@redhat.com, neal@gompa.dev, asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Daniel Wagner Subject: Re: [PATCH 3/4] nvme-apple: move blk_mq_update_nr_hw_queues after nvme_unfreeze Message-ID: <20260210154108.GB2484@lst.de> References: <20260209082953.3053721-1-yukuai@fnnas.com> <20260209082953.3053721-4-yukuai@fnnas.com> <20260209145832.GC18315@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) On Tue, Feb 10, 2026 at 08:09:08AM -0700, Keith Busch wrote: > If you leave the queue quiesced, pending IO will form requests that are > entered and waiting in the block layer. You can't freeze a queue with > entered requests. > > We unquiesce first to flush any pending IO that had entered during the > prior reset. It's not the best way to handle this situation. It would be > smarter to steal the bio's from all the entered requests, then end those > requests, then resubmit the bios after the hw queues are initialized. We > don't do that because no one's really complained, probably because the > queue counts don't usually change after a reset. FYI, Daniel Wagner had been thinking about doing this reinsert for something (I forgot what exactly), and this kind of reinserting from kblockd would also finally make REQ_NOWAIT practically useful for file system initiated writes. So I hope we can eventually get to it, and it should help to sort out various problems.