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 C5CC3381AFA; Wed, 29 Apr 2026 17:21:18 +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=1777483278; cv=none; b=IQo1+WMGP6MPIbpnn7NIHnqhefMAvmy85OMzY3Q0YvnLhHG4q9gD2EuAUwHn7NwMLdGcR7BBsLkR1V++cjEhTHt4g1LwyayEbiTI9CQH9rZGi1WMeVIXp0gAG18jMC4QiqUbM4lIREbPtjHQqnvZEX9EuZ79OF+VadiEtrr9PoM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777483278; c=relaxed/simple; bh=t7i4sW+nUd3seEDXvZIMITm86tFwI6EhlGV8sUQPar4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ua9uxj87BQcG5F7ff1cxpKig6mr8xT9JdEdQtct5bJ0WpLe8H5ZzyFuOsJXGYemXpxCOiwjyMlZs2O3HSqZQZt8XaIyxAHveoNmmX8HkjCf56YFhhK3q5zhJ7kRmy9PV7yBDk4udvOZySWMPnKXxGvvldyW/BgioSd0yYAXdYb0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lSS06cED; 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="lSS06cED" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2C62C19425; Wed, 29 Apr 2026 17:21:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777483278; bh=t7i4sW+nUd3seEDXvZIMITm86tFwI6EhlGV8sUQPar4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lSS06cEDHAGA6lndfSJPRYJPxML0fRDNbeu4injgOo5Sv7sN/ZLBGpujZDhS6Qqgf u/SUYacTc68rlv5hB4ArtE8VM3kz2Exc1MSsY9mICOWnjl8k8d5UzVBgE9wJIUloGY ntHgtfb3K59UBMtaFkbp74aKKvmbCw9oMSodKbOnQmPqcqjWgjfvViU7Jhd4eeYBAz l4qG3OaKgU3nh5UtEL7dmz+Y9eE3xWXCE6rYr1Az8wxAia40fAq+6n3REYArfZNGpA UPoS5FLrIERmQ1P4fy8Hvxcbiwbwh+c4T9BTLCM6KJ821HInQVBY34jvlQsE4Jpmte gqoESpIy/lU2Q== 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 , Yury Norov , Frederic Weisbecker , Yajun Deng , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v3 1/5] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices Date: Wed, 29 Apr 2026 19:20:28 +0200 Message-ID: <20260429172036.1028526-2-hawk@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260429172036.1028526-1-hawk@kernel.org> References: <20260429172036.1028526-1-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 47417b2d48a4..7a1a491ecdd5 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2048,6 +2048,7 @@ 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 @@ -2462,6 +2463,7 @@ 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 e430645748a7..4360efc8f241 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