From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout11.his.huawei.com (canpmsgout11.his.huawei.com [113.46.200.226]) (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 6313C17A300 for ; Thu, 23 Jul 2026 01:24:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.226 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784769853; cv=none; b=cMsji+Y7dHUXalrowCFMmas3EN0M1Pl0r7YDnTzlaRqzS4l2Rc28z9cjXBegd+Ys90wyKy094Io19Jtk2aX6fKaszPkEOh7LG5PbmXpZC9lyI6V9FJCOBa5EibSIB35z+SDF6AxPjh/jIK0yDw0L15e73c6nqPq3/emBvVbjfuA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784769853; c=relaxed/simple; bh=rH1Wsn71inUuK+5SZQRNnGRTJnf9ht5PVLOthcrA6zM=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=h5Who6ByYbzwqhKTVnx3JLl2IPh41oL+6384UKtNpDbA6MZ0lh7ONDXuqDymfWT9ZrBSvcNUXi9o07HDla/rFb6G/GbJ+QzOHxUhq8Oa/a6KNDCF/tlLDpSMNgp7rNf9lPdWCtGKUpawuD/0TxaC/ZU/xdrP81aDRZigNS/PFtM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=EgzBmZm9; arc=none smtp.client-ip=113.46.200.226 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="EgzBmZm9" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=tI7jlf2gVhufqXJTBiWI992LoBfe5J6nfmLVFkrOcDg=; b=EgzBmZm96DW8DjprCUcns96A0qgQEyc5VDk91CR32PxulQHKzL7WnmErmPZt7IXUwpM28L+Vg DOVjgGHyyx1K/eW83Pm/tg337SFOK1LDFp7zfBgX3a/GF9xS1QlPNUM+oSlf0RNG6o8wd3Delih VbZE3/rCPF5mr7iCabfqYmw= Received: from mail.maildlp.com (unknown [172.19.163.200]) by canpmsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4h5Cp870yszKm5m; Thu, 23 Jul 2026 09:14:40 +0800 (CST) Received: from kwepemf100006.china.huawei.com (unknown [7.202.181.220]) by mail.maildlp.com (Postfix) with ESMTPS id 8A9024055B; Thu, 23 Jul 2026 09:24:06 +0800 (CST) Received: from [10.174.176.240] (10.174.176.240) by kwepemf100006.china.huawei.com (7.202.181.220) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Thu, 23 Jul 2026 09:24:05 +0800 Message-ID: Date: Thu, 23 Jul 2026 09:24:05 +0800 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 6/6] nbd: add nr_hw_queues module parameter for pre-created devices To: , , , CC: , , , , , , References: <20260713065644.1637594-1-yangerkun@huawei.com> <20260713065644.1637594-7-yangerkun@huawei.com> From: yangerkun In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To kwepemf100006.china.huawei.com (7.202.181.220) 在 2026/7/22 11:53, yu kuai 写道: > Hi, > > 在 2026/7/13 14:56, Yang Erkun 写道: >> Previous commit can help remove all freeze for netlink newly created nbd >> device. But for the devices pre-created at module load(nbds_max default >> as 16), the nr_hw_queues was setting default as 1, then ioctl/netlink >> path will set the real connection count, and blk_mq_update_nr_hw_queues >> in nbd_start_device will introduce freeze. >> >> Add an nr_hw_queues module parameter so that users who know their >> expected connection count can pre-created devices with the right queue >> count to avoid this freeze too. > > I'm fine with this, but this is misleading. Please also add comment to > emphasize this module parameter is just to avoid queue freeze if user configure > the exact number of socks as this new module parameter. Otherwise, the real > nr_hw_queues is still depend on the real number of user configured socks. OK, will add this comment in next version! Thanks a lot for your careful review! > >> >> Signed-off-by: Yang Erkun >> --- >> drivers/block/nbd.c | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c >> index 2c7b09c70da2..f918c9efa9b2 100644 >> --- a/drivers/block/nbd.c >> +++ b/drivers/block/nbd.c >> @@ -166,6 +166,7 @@ static struct dentry *nbd_dbg_dir; >> >> static unsigned int nbds_max = 16; >> static int max_part = 16; >> +static int nr_hw_queues = 1; >> static int part_shift; >> >> static int nbd_dev_dbg_init(struct nbd_device *nbd); >> @@ -2752,8 +2753,10 @@ static int __init nbd_init(void) >> } >> nbd_dbg_init(); >> >> + if (nr_hw_queues < 1) >> + nr_hw_queues = 1; >> for (i = 0; i < nbds_max; i++) >> - nbd_dev_add(i, 1, 1); >> + nbd_dev_add(i, 1, nr_hw_queues); >> return 0; >> } >> >> @@ -2814,3 +2817,6 @@ module_param(nbds_max, int, 0444); >> MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); >> module_param(max_part, int, 0444); >> MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)"); >> +module_param(nr_hw_queues, int, 0444); >> +MODULE_PARM_DESC(nr_hw_queues, >> +"number of hardware queues for devices pre-created at module load (default: 1). "); >