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 7275EEA8134 for ; Tue, 10 Feb 2026 15:41:27 +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=p2rI3ezgSJDvYU/zB9i3pbGBVSddFqhX+QJFcTpTwhA=; b=ELmu1DQBg+cNxI2vMyP9cKDl8L qDJMzcDOXg2hyBLW+NzWhoGPIxXkvHF7Ogak8ZUXn5st1Qq5Hh3ubItLqmZCU2a3uUZvITp42GHy2 0wE4nlaLfmvopO/Py3YcdTMgzQOgoOCAkITwI7LAt18cBlWECp5mgYjsprP5ZBkZ37u7O1/94WxUP wBAtws33ThJtvHSERJ0Z+4pZtjJ451H1THz1o/Am99jIQHfcInpVzYvqmcmafrTmuQF1fGgimGYoC EC/8zJDtoZPQyer82xKN4cI7ncWDInZhXEGzrL/3ZgJ1DWfIywOJcsCBK58uElxViyRGdQxAwKZ25 RDVFKE+g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vpprd-0000000H8Vj-2UxT; Tue, 10 Feb 2026 15:41:21 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vpprZ-0000000H8Uo-1BFf; Tue, 10 Feb 2026 15:41:19 +0000 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> 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) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260210_074117_464247_3DA4D7FC X-CRM114-Status: GOOD ( 15.03 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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.