From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (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 B8BC3388371 for ; Thu, 7 May 2026 22:20:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778192404; cv=none; b=dv3kQMmMtxf2NXepR2/CrLz70EGNgwHQ8h3U2u6GXdaZhDaFgodFfJ6XziyS7QuWYweemtDVP9L1o1CO3uQ6N6wreSL75qQqQfw1MrPb/krwErRUzeTxsuoaWRQ1VCy6ItVyUvKShYGeMuDsjb2g+Q3b1qDHxeU0DfKiqz0W2u4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778192404; c=relaxed/simple; bh=/YR3vuDtpjtlhVJl+QJZR6rMuQOvtGVeONiE2eAxYvQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=UUgwMw1mgdy8HyEYGcWyLQs83MZZAIwzqNSAk+PH8gCzsBiW1xh9/8r1SBmH6gHLQy8IxbW3gYPyyN3Ld5BSF3Y0jhmMDddRoccVUeOFvP2iwZi7n20t89ikCg56KlfMoMSKPffiNvQbxW83rgHcCH7tkeULx2gDKKtv3xiYFYM= 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=vJ0XZ9m0; arc=none smtp.client-ip=209.85.128.201 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="vJ0XZ9m0" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-7bd5c421975so2423427b3.3 for ; Thu, 07 May 2026 15:20:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1778192399; x=1778797199; 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=qgc+rECRk6r9633P3FdEBKCP+zSKjzSEVv6feaKe6TA=; b=vJ0XZ9m0SCXvS1X+x1hqPeKPxVK1UrPZ9iQH/M0Fo0tfrr5ysSlIQ+ynBQPUFNUKGV jQiMJMdmSlyviB0x92To5eYjxfSmvqhO5htarOKxMtS3kBnKYxMUMOWjHE9M/jkr/GkA YjVvfb6JMhx95CGfFNwAocH0tWcPpcq11XnZR+t9RdZyTAQw3Sv+FPEtbNZHAl+JeewC w9/w1TLvSK7LH7fzCKWGBHMXECejww1wx/os381AUCsuSlJ3GgyNLE2P6YC6svGRfN7v KoIHCGk67cA8DheXwJPaaKuCLwlgqw5hU0GhctSStGcSC+By4mMNfq5km2BXS3fA4Tj0 iDxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778192399; x=1778797199; 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=qgc+rECRk6r9633P3FdEBKCP+zSKjzSEVv6feaKe6TA=; b=r+XYzwESdw5B4fZZfsNfDFngjhDZecULz07nELw0peExmfDymXTuut5dfvWRjTPQDR H+G5n1z5bIEXePNjDW/9FmI4b3vcdffee4dAkB40nI86si8MhbOOzFlYTG3fsk9WuYmF lUt15sIyOsALRkmOqaimh2DH1uIqTuHah1WQZ22vEK7H30vAzwMHWErZB1GnAp9zeb2R DggpQ0F+KyncWXcFiNkSCyjOzPm7t0uEbpsZQkrT815b3lLWyhn69ejK72oBS6Q1fOdF nZzBZ+7YbD9rR2kFuSNHNeuo/jtglxnDi5hQVqgRWj7A/IGrNDvHEZor6WpHncDSzdyt jflg== X-Forwarded-Encrypted: i=1; AFNElJ/cJzOdz9zcQUtiX7ndbUsrbKE7QhdaYJ+ScjnRFN8ltbOViwukh19BKed71gmKtwg4BLWCbrM=@vger.kernel.org X-Gm-Message-State: AOJu0YzGkm5jusRiJMwEdGdSxddeshL/pqO5UCcO9Qn0A4FfXkVNSfQg o28d2L+bYHpM+fcjZH7eT1irlU6SMBkvDteWbTd409Asbl3M+Mny8nZpyfo7FfnvyEK98TeOKT0 MGXShJLko/kMF5Q== X-Received: from ywbew2.prod.google.com ([2002:a05:690c:2f82:b0:7bf:75a:fbc2]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:690c:d95:b0:7ba:d5fb:b579 with SMTP id 00721157ae682-7bdf5ea84c5mr110419957b3.36.1778192398819; Thu, 07 May 2026 15:19:58 -0700 (PDT) Date: Thu, 7 May 2026 22:19:46 +0000 In-Reply-To: <20260507221948.335726-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260507221948.335726-1-edumazet@google.com> X-Mailer: git-send-email 2.54.0.563.g4f69b47b94-goog Message-ID: <20260507221948.335726-7-edumazet@google.com> Subject: [PATCH net-next 6/8] net/sched: mq: no longer acquire qdisc spinlocks in dump operations From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Jamal Hadi Salim , Jiri Pirko , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Prepare mq_dump_common() for RTNL avoidance. Use RCU instead of RTNL, and no longer acquire each children spinlock. Signed-off-by: Eric Dumazet --- include/net/sch_generic.h | 9 +++++++++ net/sched/sch_mq.c | 30 +++++++++++++++++++++--------- 2 files changed, 30 insertions(+), 9 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 3070a717bb98386838f3e8149f34d52572fe208f..bfd1167ed575e5154c52a4491194e17e3998977c 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -952,6 +952,15 @@ static inline void _bstats_update(struct gnet_stats_basic_sync *bstats, u64_stats_update_end(&bstats->syncp); } +static inline void _bstats_set(struct gnet_stats_basic_sync *bstats, + u64 bytes, u64 packets) +{ + u64_stats_update_begin(&bstats->syncp); + u64_stats_set(&bstats->bytes, bytes); + u64_stats_set(&bstats->packets, packets); + u64_stats_update_end(&bstats->syncp); +} + static inline void bstats_update(struct gnet_stats_basic_sync *bstats, const struct sk_buff *skb) { diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c index 4172ec24a43d1c2fe56789986a46da93eb522721..6bb1042e4595b50c6023d3ad81706ad7ab6fe0e5 100644 --- a/net/sched/sch_mq.c +++ b/net/sched/sch_mq.c @@ -143,30 +143,42 @@ EXPORT_SYMBOL_NS_GPL(mq_attach, "NET_SCHED_INTERNAL"); void mq_dump_common(struct Qdisc *sch, struct sk_buff *skb) { struct net_device *dev = qdisc_dev(sch); + struct gnet_stats_queue qstats = { 0 }; + struct gnet_stats_basic_sync bstats; + const struct Qdisc *qdisc; unsigned int qlen = 0; - struct Qdisc *qdisc; unsigned int ntx; - 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, + gnet_stats_add_basic(&bstats, qdisc->cpu_bstats, &qdisc->bstats, false); - gnet_stats_add_queue(&sch->qstats, qdisc->cpu_qstats, + 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); } EXPORT_SYMBOL_NS_GPL(mq_dump_common, "NET_SCHED_INTERNAL"); -- 2.54.0.563.g4f69b47b94-goog