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 22BE13603FC; Fri, 1 May 2026 07:16:51 +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=1777619812; cv=none; b=P3ub+hg2W22WU3ITCDG0LfznaNoeHmib47RKGJqdCacc+aqAIynLUHmPzQKHsUK3v7iGgpJVCSP2ikraVqY9rhxlP0tAd3Xm+jk4/GLVEBvvCbd0B8LUJEJNjHs6l33GPK0VWhgAhHLAiXyYYl4fOnw8OcO41iC0GiwA1Tf5IXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777619812; c=relaxed/simple; bh=TGV07DBPGVudFV2XaWmPCh5YUdCUHLGODKIAM4ubtzE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ugXJXp8y9JYrLMRCVgf5FseKmDorpWxkHpEKEsZMcl8Xr1sjbgjoHiFDa0QkoK187imGL3KvyTAcmnl36GsTKR082SzFtoH3aiXqODDncf/eg0bxkilJiYt0HkroIXqxqVvxQD3ZE3wYIedG7Z7arkz9m5J+2VUkr+cNCjUtaXM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q8L8d0+X; 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="q8L8d0+X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65C59C2BCB4; Fri, 1 May 2026 07:16:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777619811; bh=TGV07DBPGVudFV2XaWmPCh5YUdCUHLGODKIAM4ubtzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q8L8d0+XD4IW69ONlPLPlaPTzu9hUnGdt+8Z9wnHLb8wDGBpwcvnGXLLmGwAKiVM2 3uWvgoUIYU+6MclleUDYpvixzDSZNaTACqVlD6ESdJOOjU00/wPOiwBEtyGLXZZnln RLaVhLPYfr3PYJkB/OrNcgOJpn1cSfcltRdDkcjbNhXmBNXYHenXRGiyRVsI52PVKO V5JxVxSJCEjz1/jB9L4Cn/TzpsXg3WhwDZRsDcYfUaGaiRDlyGNyiPIOd+ZWoay1b/ CsrfU7XN4PmxO68oMLxzZi3BoBhKhNqZ0piEGe1WmnmW7V0F4VcQPD4+nRXz3FZG5l c8zid5N55O5hA== 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 , Frederic Weisbecker , Yajun Deng , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v4 1/4] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices Date: Fri, 1 May 2026 09:16:28 +0200 Message-ID: <20260501071633.644353-2-hawk@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260501071633.644353-1-hawk@kernel.org> References: <20260501071633.644353-1-hawk@kernel.org> Precedence: bulk X-Mailing-List: netdev@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 0e1e581efc5a..405bdf9172ca 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