From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f201.google.com (mail-qk1-f201.google.com [209.85.222.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 82C5D34F46D for ; Sun, 10 May 2026 09:15:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778404510; cv=none; b=I/T7fVq+yggA5vbeOXxTJlURLKGkMHzQ7t+RqTKX3x3S+YOZZoTJ2QljWI2tEpwvAv/5dTLY6MCBFcmvmVAXzCH/JWoAQqLlf7HQtCqAzD0AYl/vkgvtrlUCmy0Tc5LqSmTC/yP8VsPvqJ785miuu0dlCTkfZupbX+O32yAlLpw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778404510; c=relaxed/simple; bh=ZnA3OX5Xt/apyS28AXIW8yr/TiZkevmfw7z3GC755Eo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=S9zc/cdRG87pfRia22ytjGZbKkpzBVSAy6XzJKOr6ZpyprQIh8s1yRvT2MDgvV1unM7r6usxVMSItIUXnjQcJa57QqL8OKbP52RCVKyZTmvzZmjmFG05evRBERZ/O0bC2pNl1JyU9NCJhVB9jeWu7yrvXnE0umV605nzoXDDg3s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=OXes6/9q; arc=none smtp.client-ip=209.85.222.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OXes6/9q" Received: by mail-qk1-f201.google.com with SMTP id af79cd13be357-8d4c2906fdfso80497885a.2 for ; Sun, 10 May 2026 02:15:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1778404507; x=1779009307; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=azugEo5okkeBZmSkhwS7WZylwD7Rsm5DuJws2ETZDV4=; b=OXes6/9q0gI75HGFGXCiOlmCxlH/I7xvXZ0E3OGehl4yt07d8TdhnTLVpYNrhd1rjh zKIa13ql2jMVaNEZd7mV1Mwfum7wHvl+nG6WUK/nW61QjiOP0/wSulBHsLvrXKgeNBdO cUc/hj8vqNG3JqlotMliGdF7F27KWzEqQlcLlfA+wIGkk/mGcsa1JwRRQMkuiQagfnrH MzKyV/mYmd+hCpThp3tnZ26UgEtlXvGLgH6fQv1j0q11DUhekjqL2XNKMtzy1Q5GHL8D FKaFj8nasgyIAZ3dDPajSGwRxQBE0pJjnbIiiq4+jQnZWnhRXbCLk8Zt3n3HBp8itW6j 6jrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778404507; x=1779009307; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=azugEo5okkeBZmSkhwS7WZylwD7Rsm5DuJws2ETZDV4=; b=irjsX0nDwVkB9ArHLfo1FN80bu7uaId76QvqtWKTQEb1Adb5ywtBwN46xZljud5ahs Z6QyhCO6Wy2cjiz+0mIWDXThug6oSso+VpOElzigH7PB+mNMXtsDKRT0RaPuHX6USX+2 aCsMYIFWETa4Blns6eaCFRKnFXt9fNWdac8g3C1rN0azZlS+kBffh5OCc1HZrw2YDM8D nNM3rAk3B/us8rRs6kfZRMTtSL6By98ldF/tNew57wK8qC5uHV5zYtAtnxHxYmAcfPHJ S+Mo5flZiR1nM3TpQkDCm5iK52nSzLWBvRMNqdGVjNhn8D/ETpkg0sjsa2vRrKGX4VTx EJLA== X-Forwarded-Encrypted: i=1; AFNElJ8voJw/nndC3nscbqokvHFCQX3KDfgJGe0lVbdSDU1GJWhizJiR7xeI/o8yhKUC/hTfrcYjcVw=@vger.kernel.org X-Gm-Message-State: AOJu0YxdAQOgdEZqsFvFrDLa4/Ax9ubhI56X2Dot+GYi6s0u3Lgm+ooe 38ps+E7GMz1kEWWYIKw4U7ztnopDrTCb1Nu78lPNvrmPOB5fj8Yau0fryAoP7D+ZgMW5zgp4BeM 978JXmV+T/C5Tng== X-Received: from qktt29.prod.google.com ([2002:a05:620a:5d:b0:8d4:6c04:dbf7]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:29c1:b0:8f0:f1a5:680c with SMTP id af79cd13be357-904d60f5805mr2968151985a.29.1778404507046; Sun, 10 May 2026 02:15:07 -0700 (PDT) Date: Sun, 10 May 2026 09:14:54 +0000 In-Reply-To: <20260510091455.4039245-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260510091455.4039245-1-edumazet@google.com> X-Mailer: git-send-email 2.54.0.563.g4f69b47b94-goog Message-ID: <20260510091455.4039245-8-edumazet@google.com> Subject: [PATCH v2 net-next 7/8] net/sched: mq_prio: no longer acquire qdisc spinlocks in mqprio_dump() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Jamal Hadi Salim , Jiri Pirko , Victor Nogueira , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Prepare mqprio_dump() for RTNL avoidance. Use RCU instead of RTNL, and no longer acquire each children spinlock. Signed-off-by: Eric Dumazet --- net/sched/sch_mqprio.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c index 3b4881c389c535368687454ea268bec892ecb942..f9dab76f40ebbd1363121198bbc3af2bd951c101 100644 --- a/net/sched/sch_mqprio.c +++ b/net/sched/sch_mqprio.c @@ -551,35 +551,46 @@ static int mqprio_dump_tc_entries(struct mqprio_sched *priv, static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb) { - struct net_device *dev = qdisc_dev(sch); - struct mqprio_sched *priv = qdisc_priv(sch); struct nlattr *nla = (struct nlattr *)skb_tail_pointer(skb); + struct mqprio_sched *priv = qdisc_priv(sch); + struct net_device *dev = qdisc_dev(sch); + struct gnet_stats_queue qstats = { 0 }; + struct gnet_stats_basic_sync bstats; struct tc_mqprio_qopt opt = { 0 }; + const struct Qdisc *qdisc; unsigned int qlen = 0; - struct Qdisc *qdisc; unsigned int ntx; - qlen = 0; - gnet_stats_basic_sync_init(&sch->bstats); - memset(&sch->qstats, 0, sizeof(sch->qstats)); + gnet_stats_basic_sync_init(&bstats); /* MQ supports lockless qdiscs. However, statistics accounting needs * to account for all, none, or a mix of locked and unlocked child * qdiscs. Percpu stats are added to counters in-band and locking * qdisc totals are added at end. */ + rcu_read_lock(); for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { - qdisc = rtnl_dereference(netdev_get_tx_queue(dev, ntx)->qdisc_sleeping); - spin_lock_bh(qdisc_lock(qdisc)); + qdisc = rcu_dereference(netdev_get_tx_queue(dev, ntx)->qdisc_sleeping); - gnet_stats_add_basic(&sch->bstats, qdisc->cpu_bstats, - &qdisc->bstats, false); - gnet_stats_add_queue(&sch->qstats, qdisc->cpu_qstats, + gnet_stats_add_basic(&bstats, qdisc->cpu_bstats, + &qdisc->bstats, true); + gnet_stats_add_queue(&qstats, qdisc->cpu_qstats, &qdisc->qstats); qlen += qdisc_qlen_lockless(qdisc); - - spin_unlock_bh(qdisc_lock(qdisc)); } + rcu_read_unlock(); + + spin_lock_bh(qdisc_lock(sch)); + _bstats_set(&sch->bstats, u64_stats_read(&bstats.bytes), + u64_stats_read(&bstats.packets)); + spin_unlock_bh(qdisc_lock(sch)); + + WRITE_ONCE(sch->qstats.qlen, qstats.qlen); + WRITE_ONCE(sch->qstats.backlog, qstats.backlog); + WRITE_ONCE(sch->qstats.drops, qstats.drops); + WRITE_ONCE(sch->qstats.requeues, qstats.requeues); + WRITE_ONCE(sch->qstats.overlimits, qstats.overlimits); + WRITE_ONCE(sch->q.qlen, qlen); mqprio_qopt_reconstruct(dev, &opt); -- 2.54.0.563.g4f69b47b94-goog