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 E3D9E1487E4 for ; Wed, 17 Apr 2024 17:07:43 +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=1713373664; cv=none; b=kXzhPIPvPen9uvHdbzcCmsc+MgvWVN4Jzbm/24IJPhPNcYh7sYy6bi4+bU2+pz9kDYPNPPVmzPeh1m7p0nk25oPSBTFlecj+2GhNG8RoMf1RGHCBKOL0UjKF5qVBKyW7CkLRfal+l86I/ElSk/kehA0xxv36n91hIZUOxXVP+kw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713373664; c=relaxed/simple; bh=vL7dNHHMoYA9aVz5zI+6e61+WjGY7AhETSRX0cYKQ8Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s9nMyER6sUIEvZzn8IHUlshOZnZpuqr2fx1f/vygVrr0i3nDknh+UEdqmr2HqXllrmfAMdoVqfJjFVbrVbx6Uzq3J5fU3KKL/DMcIQ1O2e7oZ0GKKTzXxUjIY8nYJbU5KP6fjFd947HIrolxSL/sx9DBj/bGvWQCB3CXTHiW22o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=belNWJ8b; 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="belNWJ8b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95CB4C072AA; Wed, 17 Apr 2024 17:07:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713373663; bh=vL7dNHHMoYA9aVz5zI+6e61+WjGY7AhETSRX0cYKQ8Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=belNWJ8bxbuKiydIdvtqopuK6u6DgHEnaAgakNNyncai2qRWOLg//r+DBhFkAcgHS RZrYTSSME5Oz4/djGu0oSPpuqpTXZPgnbHZ1YcVRZz71CCX7vFveiAgRSBFM5TYmpu dPZ6UEg+GnYTVfCggWQD5/sk8+c1ibC80YBQMyglPXPMUwQ8N1VW6twmHqAe0Rq4aO jrYT+nMmKujuc4eknWE5rYPhnsRMLXuRsid9W+6rcy31Li0lsSZi1NmYVvrczlgvLq NLWd9CiLDQKKdkZCDeygDb8fC0a9U6zhc5whIpnRWd1Y6oNd24RzoMP9bZ4ev3E4TQ nSlDMjt4rB/AA== Date: Wed, 17 Apr 2024 18:07:39 +0100 From: Simon Horman To: Eric Dumazet Cc: "David S. Miller" , Jakub Kicinski , Paolo Abeni , Jamal Hadi Salim , Cong Wang , Jiri Pirko , netdev@vger.kernel.org, eric.dumazet@gmail.com Subject: Re: [PATCH net-next 09/14] net_sched: sch_fq_codel: implement lockless fq_codel_dump() Message-ID: <20240417170739.GE2320920@kernel.org> References: <20240415132054.3822230-1-edumazet@google.com> <20240415132054.3822230-10-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240415132054.3822230-10-edumazet@google.com> On Mon, Apr 15, 2024 at 01:20:49PM +0000, Eric Dumazet wrote: > Instead of relying on RTNL, fq_codel_dump() can use READ_ONCE() > annotations, paired with WRITE_ONCE() ones in fq_codel_change(). > > Signed-off-by: Eric Dumazet > --- > net/sched/sch_fq_codel.c | 57 ++++++++++++++++++++++++---------------- > 1 file changed, 35 insertions(+), 22 deletions(-) > > diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c ... > @@ -529,30 +539,33 @@ static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb) > goto nla_put_failure; > > if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET, > - codel_time_to_us(q->cparams.target)) || > + codel_time_to_us(READ_ONCE(q->cparams.target))) || > nla_put_u32(skb, TCA_FQ_CODEL_LIMIT, > - sch->limit) || > + READ_ONCE(sch->limit)) || > nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL, > - codel_time_to_us(q->cparams.interval)) || > + codel_time_to_us(READ_ONCE(q->cparams.interval))) || > nla_put_u32(skb, TCA_FQ_CODEL_ECN, > - q->cparams.ecn) || > + READ_ONCE(q->cparams.ecn)) || > nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM, > - q->quantum) || > + READ_ONCE(q->quantum)) || > nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE, > - q->drop_batch_size) || > + READ_ONCE(q->drop_batch_size)) || > nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT, > - q->memory_limit) || > + READ_ONCE(q->memory_limit)) || > nla_put_u32(skb, TCA_FQ_CODEL_FLOWS, > - q->flows_cnt)) > + READ_ONCE(q->flows_cnt))) Hi Eric, I think you missed the corresponding update for q->flows_cnt in fq_codel_change(). > goto nla_put_failure; > > - if (q->cparams.ce_threshold != CODEL_DISABLED_THRESHOLD) { > + ce_threshold = READ_ONCE(q->cparams.ce_threshold); > + if (ce_threshold != CODEL_DISABLED_THRESHOLD) { > if (nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD, > - codel_time_to_us(q->cparams.ce_threshold))) > + codel_time_to_us(ce_threshold))) > goto nla_put_failure; > - if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR, q->cparams.ce_threshold_selector)) > + if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR, > + READ_ONCE(q->cparams.ce_threshold_selector))) > goto nla_put_failure; > - if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_MASK, q->cparams.ce_threshold_mask)) > + if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_MASK, > + READ_ONCE(q->cparams.ce_threshold_mask))) > goto nla_put_failure; > } > > -- > 2.44.0.683.g7961c838ac-goog > >