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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7446C433EF for ; Tue, 12 Oct 2021 15:03:12 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 69E1D60527 for ; Tue, 12 Oct 2021 15:03:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 69E1D60527 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=p2zKnuVv4/jGoNM5e4TR8KNjLzv28qzsqbbDFbLImEc=; b=PEt5J8OZ9kKvJa HqfRPvMXYUJATt+81wh6hxeSVP7S7dFDLV7y48RUB1R0ZRm5cdBBNGi3zhyl9uMSy/kCbwVXF3640 dOnQmuS19sQGImypwEbYk4jKLqTkRmVcNLcgkSS/gFfhZwowuAj26sHu/fJ/PiW2RTbq4S6SYdI1v 90qSxIWw6YlR2gzLiIghhm8LyAMin0JUjVeckOMqjKeUvIy3FBKUCsb+gG68DBDN3PHRvyPLzkpWS N8NBOyWit2JCmiE6POT4nRFd6Kt5JAXEupoWX5ylYOT3az8euiIW+SgqDGgdyDFzi39p7qqCFyw0x NuLEb9Y+zqpGigfpRm5Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1maJIe-00DHYn-L3; Tue, 12 Oct 2021 15:02:40 +0000 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1maJIb-00DHY3-Fn for linux-nvme@lists.infradead.org; Tue, 12 Oct 2021 15:02:39 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634050954; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H5n0vZXzpKUr4bdvWBgiF2GxyHPbprOqb+7u3O+dEug=; b=OZXaj8MdraQzsfikS35WDWRJLzHZNmv7WK/bVKyH6/cUTxz4CnP+963Bx85R8bjPLg3jfO YeF7EPP7XfFddM3DxtqEp2ZfHtv1Y6XwHoau7AHYjqDtiN3P32Ct6F7YTDC1wndbGD5hjC o3t9LrLH9OCbKMBPalTkcFXFRIOKj7E= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-295-jiS4h6U3MFWVJ22ABzKX0Q-1; Tue, 12 Oct 2021 11:02:31 -0400 X-MC-Unique: jiS4h6U3MFWVJ22ABzKX0Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 856CF80158D; Tue, 12 Oct 2021 15:02:29 +0000 (UTC) Received: from T590 (ovpn-8-34.pek2.redhat.com [10.72.8.34]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4CCE82B060; Tue, 12 Oct 2021 15:02:24 +0000 (UTC) Date: Tue, 12 Oct 2021 23:01:48 +0800 From: Ming Lei To: Christoph Hellwig Cc: Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Chaitanya Kulkarni , Sagi Grimberg , Keith Busch , Bart Van Assche Subject: Re: [PATCH V3 4/6] nvme: paring quiesce/unquiesce Message-ID: References: <20211009034713.1489183-1-ming.lei@redhat.com> <20211009034713.1489183-5-ming.lei@redhat.com> <20211012103620.GB29640@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211012103620.GB29640@lst.de> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211012_080237_668072_B708ECD0 X-CRM114-Status: GOOD ( 20.03 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Oct 12, 2021 at 12:36:20PM +0200, Christoph Hellwig wrote: > On Sat, Oct 09, 2021 at 11:47:11AM +0800, Ming Lei wrote: > > The current blk_mq_quiesce_queue() and blk_mq_unquiesce_queue() always > > stops and starts the queue unconditionally. And there can be concurrent > > quiesce/unquiesce coming from different unrelated code paths, so > > unquiesce may come unexpectedly and start queue too early. > > > > Prepare for supporting concurrent quiesce/unquiesce from multiple > > contexts, so that we can address the above issue. > > > > NVMe has very complicated quiesce/unquiesce use pattern, add one atomic > > bit for makeiing sure that blk-mq quiece/unquiesce is always called in > > pair. > > Can you explain the need for these bits a little more? If they are > unbalanced we should probably fix the root cause. > > What issues did you see? There are lots of unbalanced usage in nvme, such as 1) nvme pci: - nvme_dev_disable() can be called more than one times before starting reset, so multiple nvme_stop_queues() vs. single nvme_start_queues(). 2) Forcibly unquiesce queues in nvme_kill_queues() even though queues are never quiesced, and similar usage can be seen in tcp/fc/rdma too Once the quiesce and unquiesce are run from difference context, it becomes not easy to audit if the two is done in pair. Thanks, Ming _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme