From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B4A203A6F05; Tue, 5 May 2026 13:22:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777987337; cv=none; b=Z4IcnYS/8dRd0EkCuqayZd4jDdfQE3uGtkH7keI/6ruRKrb3SKIYCrZdRqbOYgIhtIQN3nUjOM1m1JVbFrSE7wKaQChc31pVcTogjSisBWrvqEqCPVuMr0FdWWsjpRkLMG+UhiqFDGl9OFaadOdwldFsL9xuZgK+p9tR7Pr9W0I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777987337; c=relaxed/simple; bh=dY5gAI1Fa8oDYwSxEJDa0qL3hZJGKftL43uRkTgW/9I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ciOWfX7OYjUTV9tYyz1vVcleu6q3MZnWivoMYxupltw+ikljKA49a3zhTLwl/jLPSshl5/Jcjb+57UiRYrTM8iCQUAg3UH1/w18Fs5BcZLJFcuDWBTH7Kfc345Z10XOxGEnC373tnBPO9bSHkQWvCpGTuP6WELcMGyHRUCo672s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=u2G0DsI7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="u2G0DsI7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 836BFC2BCB4; Tue, 5 May 2026 13:22:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777987337; bh=dY5gAI1Fa8oDYwSxEJDa0qL3hZJGKftL43uRkTgW/9I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u2G0DsI76aNmvAqbADJx2SwckcU14/V4uVOYdH05j8QPjUachVK0X3Hz7BHMc10Om poi1+RfO3MSF9ZL1Ncx552YLfGVi4knN72wAdUEbUXWWSA4JMaauX1C/49OhUFRKMy gJflvFT7okYLB7m4/EPWG3eJC/4H8ih+Tc+re6xkaMoqINeNcena18mSNTi6hm5iXi MgbJpXV9QkrJn4ErAbYNi/lqQMt7kMIRHRU/TvfZ794W9yXEUDvlemMsP71VK7Xby/ j6qvmwBo3Cf1AN4Cnq32HdFE3+w12r48zEIRAPQH5wVgG6j4MN+sdMGW+6mzusK1on IQdKQA6O2nmZg== From: hawk@kernel.org To: netdev@vger.kernel.org Cc: hawk@kernel.org, kernel-team@cloudflare.com, =?UTF-8?q?Jonas=20K=C3=B6ppeler?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Shuah Khan , Kuniyuki Iwashima , Stanislav Fomichev , Christian Brauner , Yury Norov , Krishna Kumar , Yajun Deng , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v5 2/5] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices Date: Tue, 5 May 2026 15:21:54 +0200 Message-ID: <20260505132159.241305-3-hawk@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260505132159.241305-1-hawk@kernel.org> References: <20260505132159.241305-1-hawk@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jesper Dangaard Brouer Virtual devices with IFF_NO_QUEUE or lltx are excluded from BQL sysfs by netdev_uses_bql(), since they traditionally lack real hardware queues. However, some virtual devices like veth implement a real ptr_ring FIFO with NAPI processing and benefit from BQL to limit in-flight bytes and reduce latency. Add a per-device 'bql' bitfield boolean in the priv_flags_slow section of struct net_device. When set, it overrides the IFF_NO_QUEUE/lltx exclusion and exposes BQL sysfs entries (/sys/class/net//queues/ tx-/byte_queue_limits/). The flag is still gated on CONFIG_BQL. This allows drivers that use BQL despite being IFF_NO_QUEUE to opt in to sysfs visibility for monitoring and debugging. Signed-off-by: Jesper Dangaard Brouer Tested-by: Jonas Köppeler --- Documentation/networking/net_cachelines/net_device.rst | 1 + include/linux/netdevice.h | 2 ++ net/core/net-sysfs.c | 8 +++++++- 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst index 1c19bb7705df..b775d3235a2d 100644 --- a/Documentation/networking/net_cachelines/net_device.rst +++ b/Documentation/networking/net_cachelines/net_device.rst @@ -170,6 +170,7 @@ unsigned_long:1 see_all_hwtstamp_requests unsigned_long:1 change_proto_down unsigned_long:1 netns_immutable unsigned_long:1 fcoe_mtu +unsigned_long:1 bql netdev_uses_bql(net-sysfs.c) struct list_head net_notifier_list struct macsec_ops* macsec_ops struct udp_tunnel_nic_info* udp_tunnel_nic_info diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 744ffa243501..d4c7b020b6a7 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2065,6 +2065,7 @@ enum netdev_reg_state { * @change_proto_down: device supports setting carrier via IFLA_PROTO_DOWN * @netns_immutable: interface can't change network namespaces * @fcoe_mtu: device supports maximum FCoE MTU, 2158 bytes + * @bql: device uses BQL (DQL sysfs) despite having IFF_NO_QUEUE * * @net_notifier_list: List of per-net netdev notifier block * that follow this device when it is moved @@ -2479,6 +2480,7 @@ struct net_device { unsigned long change_proto_down:1; unsigned long netns_immutable:1; unsigned long fcoe_mtu:1; + unsigned long bql:1; struct list_head net_notifier_list; diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 3318b5666e43..82833e5dae03 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1945,10 +1945,16 @@ static const struct kobj_type netdev_queue_ktype = { static bool netdev_uses_bql(const struct net_device *dev) { + if (!IS_ENABLED(CONFIG_BQL)) + return false; + + if (dev->bql) + return true; + if (dev->lltx || (dev->priv_flags & IFF_NO_QUEUE)) return false; - return IS_ENABLED(CONFIG_BQL); + return true; } static int netdev_queue_add_kobject(struct net_device *dev, int index) -- 2.43.0