From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.toke.dk (mail.toke.dk [45.145.95.4]) (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 000B23655C2 for ; Tue, 12 May 2026 12:11:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.145.95.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778587864; cv=none; b=jrX+LJ8giu5xL0EOL6Ucb7m0CzToRDdJ3rY5OLJw0QGRDjtbC8YtkrsPBRtqKrpvEt3e+xhDCyhPk/f6AbmuO+ekS66w3hwPD2Qif2JnnqndTiRSCRyoz9duN6+JyuQgk/9M4BjjoP9Bqb7TC3RlwLLjkLUF2Ewi0K3pCpRFE5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778587864; c=relaxed/simple; bh=VmPZKy3SeR06tX78WhRK4mTTooT8QOFyD0AleVuwmEY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=tSGvb6TKSw8stVYRpipV7/8roaW1GmzSQH1Ig1v7Dzjze7BUNdCi8CZ+Y+nHxIH1oe/QZx6TS2OFpco9+uy7REw/PiebgWK+uhp8U0fqsM8KpjS/YZpkh+JgciaAypEdWoh6D/jR21MGxgl1QurQs/gssIazuBFxNZjt4meDeVM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=toke.dk; spf=pass smtp.mailfrom=toke.dk; arc=none smtp.client-ip=45.145.95.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=toke.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=toke.dk From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= Authentication-Results: mail.toke.dk; dkim=none To: Eric Dumazet , "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 Subject: Re: [PATCH net-next 2/2] net/sched: fq_codel: local packets no longer count against memory limit In-Reply-To: <20260512094859.3673997-3-edumazet@google.com> References: <20260512094859.3673997-1-edumazet@google.com> <20260512094859.3673997-3-edumazet@google.com> Date: Tue, 12 May 2026 14:11:00 +0200 X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87o6ikygiz.fsf@toke.dk> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Eric Dumazet writes: > Commit 95b58430abe7 ("fq_codel: add memory limitation per queue") > claimed that the 32Mb default was "reasonable even for heavy duty usages." > > In practice, this is not the case. Well, the assumption lasted a decade, so that's pretty good? :) > Packets that are associated with local sockets sk_wmem_alloc > do not really need additional memory control. > > Signed-off-by: Eric Dumazet > --- > net/sched/sch_fq_codel.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c > index 1b1de693d4c64a1f5f4e9e788371829dea91740e..71107dc52be799a14f370f2ad74d2eadd93992c1 100644 > --- a/net/sched/sch_fq_codel.c > +++ b/net/sched/sch_fq_codel.c > @@ -212,7 +212,7 @@ static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch, > q->new_flow_count++; > WRITE_ONCE(flow->deficit, q->quantum); > } > - get_codel_cb(skb)->mem_usage = skb->truesize; > + get_codel_cb(skb)->mem_usage = is_skb_wmem(skb) ? 0 : skb->truesize; > q->memory_usage += get_codel_cb(skb)->mem_usage; Only one concern here: q->memory_usage is exposed to userspace in the stats, so this will look like the packets queued are zero-length to anyone watching, which may end up confusing folks? Also, there will be no way to see how many bytes are actually in the qdisc. Should we keep a separate counter so we can still accurately report the memory usage to userspace? -Toke