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 0373940B6D9 for ; Tue, 24 Mar 2026 17:47:57 +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=1774374478; cv=none; b=rwPxF1A9k0PjkQz6R4OglLdGO93U+pQQC3DfcJdTZwGmgJSFrdbH8Flf5BWo1yhUnS/g4I6LJYI8VC3vOzqTjEUpmFX2z35DC+g9AKKt73F8rLFyJAhMBd/bx2bHrrPH7Ul0bQMshdy3jtoE0JNdYIIigdXrv6rxuwgQbUyxd/s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774374478; c=relaxed/simple; bh=5t6wPUU1Rpso5ZpeFFrf81lT4S+ExPQYc+EF690GDOo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ktXsJoocH6N0aWAqjlLYDGdkn2AeG5Mv9qk5VmmwsfSw47ThooT8OlxbPLLwPwQXGXQXXcm1AspmW1Go6Bx4YLhBwsajp60BHSyHzZPQRedOfa3HZzgsQiV+EYoo9OcAudL381WakHLduH2aVEykOMAW9IIyqRGjsOGGQUVp82I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kQS0DRSV; 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="kQS0DRSV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E651C2BC9E; Tue, 24 Mar 2026 17:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774374477; bh=5t6wPUU1Rpso5ZpeFFrf81lT4S+ExPQYc+EF690GDOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kQS0DRSVTN4rcyAaqbLCvFxJY5JiB8AN6MNiPKAjhQeGhP1rT4xl6FHi61TtIMdED a1KSyOQm4ci5RKPKmoP36do4a9EGJ7wuDVjrrXVhsoKYuQ52CesQgJHPDIFMhkmvrf uaIRr4n85rPtYyBeHU8JTZ4ZRaPk2IZAggvfFN/VwXfBnJ6mTKEoQ83L6fInNkpkPK uLvppNQwpDVCwEc1Phx/Bjvorscc2uBv0ZDePx48aEUiAPLEKw5HdHM8zSAZY5fcDt oWsYoTWVJJumn4g7uT5YMpGTBYgMgb0VpiTPHK8BpXCEe3Kg9xfDH4b3lvBzDIyimd aQdc5fz2pgHGw== From: hawk@kernel.org To: netdev@vger.kernel.org Cc: hawk@kernel.org, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, j.koeppeler@tu-berlin.de, kernel-team@cloudflare.com Subject: [PATCH net-next 1/5] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices Date: Tue, 24 Mar 2026 18:47:00 +0100 Message-ID: <20260324174719.1224337-3-hawk@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260324174719.1224337-1-hawk@kernel.org> References: <20260324174719.1224337-1-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 | 1 + net/core/net-sysfs.c | 8 +++++++- 3 files changed, 9 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 67e25f6d15a4..09e8c4dc16a0 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2463,6 +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 2ce011fae249..b57f76b7e578 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