From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: mail.toke.dk; spf=none smtp.mailfrom=mojatatu.com; dkim=pass header.d=mojatatu-com.20230601.gappssmtp.com; arc=none (Message is not ARC signed); dmarc=none Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by mail.toke.dk (Postfix) with ESMTPS id 7FDBEC54BE4 for ; Wed, 20 Aug 2025 08:45:41 +0200 (CEST) Received: by mail-pj1-x1036.google.com with SMTP id 98e67ed59e1d1-32326e66dbaso4285184a91.3 for ; Tue, 19 Aug 2025 23:45:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mojatatu-com.20230601.gappssmtp.com; s=20230601; t=1755672340; x=1756277140; darn=lists.bufferbloat.net; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=/GIOgGi2jTMp7v09lKAxmABqYcMeuVEyv+PG69CHHZo=; b=bjTHhb7KhEjhyvyvPX3s+fCO9i8XZRD3hA+CppYwdI94C+tSQ8X6SiEiVmDKpL1zyM /0JLcOwBjmM8VUxcSSbHUfscMH58aZC5UGX6kwoYmwoyzd4UqjovcUHO73c+7G87YzVN /IVucmC+XC9dhQZ3rRCqzDXkYb0ePVmF1a+DfH36yJb8iCZC1ot6J5IwBq5y386BlzER i1zdlRjumRDKe3IJJWZQTCZ3gUZQJXJEJZ4NpXjRAUSAPZOYObGfdO0dNhUeoawOEyOf 6P+LUmRAGyy17jkxfKyBb3lWBYnBN7dq8okfyVh2t92yMsQ6QBC2sMs5aAUpN3TG6+Cu Ifyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755672340; x=1756277140; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/GIOgGi2jTMp7v09lKAxmABqYcMeuVEyv+PG69CHHZo=; b=WkUx6gig/OvvDRBoY3qxFlbW3QBf5aP6KUvig3SO7hO1HtcB/ut6r7FMwVCQHHp+a2 7/QvUfupoDZE2H/CA75KETc0vNfv1ogYbRnnphgpZTxake/oKuspmYVqN04Au6rbDEcw aM+Ds5coJh2eTn4aAVdOYDQHwqhOEAyeFzO2wjrBFuQH4FeHCGwswoN/dhArcCn0zu5x o3UW9ov/PfLMdskwgVAbx36euHH855EJ1xN+c9/lCvXypuuw8mCSg2IxWeVrelryTEFU rzm0QLj0Y7k623jdl+XiZC+De/AwRRtFJv8GiDjjafMJhlQdtAk2AuGs64m4Kk17XiGj eZ1Q== X-Forwarded-Encrypted: i=1; AJvYcCW3fqPtmvwU4Xn4R9btzv3s/ijqvJYoMe8R6PIZhQw6QL9pjJK05/bmiIsy/nefoDYXRSaE@lists.bufferbloat.net X-Gm-Message-State: AOJu0YzgJUfZVRxJSuFL1UU9n+3bBrkgzPswjRTRo46LpPFY/1U2Hsab GJ8vSh+/oyv7dXyNXiL5X49ECIeSe5WHeGakAB6A/4UivAaNret4rM7V7pwHYWF/YHTHhPHh1AT CUMMR25uq8XENvx8KAwd0uolwhILpoBi5BUlQd1n8 X-Gm-Gg: ASbGnctqJ0hMdK3HLOUbxlgnfDpJFqfIUEdd4jsqizNxP0ntnicCfbtYu/hbiaRD8bs AkPw3kQl0kTdeog8gpnS1F7idUnK9gOITuAa26fvM7D52JKmLV4BwzxFOT89Ewx2qLxQaFT9xpS WqmyVbEUi0N07QkWMnszq/N8nP5C0HudcPYiotltWZxSmUdErDDCfD5ucnD4gzKk2E8la2geIxv g7e8xAIOlKvU2l5 X-Google-Smtp-Source: AGHT+IEDERn0WICGs2a8Kah+93iHICYYCy1ydZIzCJ9Yr3/+Mq9XL1oBmswjXnt5iJUMbq0tBuuTmgt9TYnYSV9cy6k= X-Received: by 2002:a17:90a:e70c:b0:312:e731:5a6b with SMTP id 98e67ed59e1d1-324e147375bmr2009084a91.32.1755672339752; Tue, 19 Aug 2025 23:45:39 -0700 (PDT) MIME-Version: 1.0 References: <20250819033601.579821-1-will@willsroot.io> <871pp7k82y.fsf@toke.dk> In-Reply-To: <871pp7k82y.fsf@toke.dk> From: Jamal Hadi Salim Date: Wed, 20 Aug 2025 02:45:28 -0400 X-Gm-Features: Ac12FXxVXwHmUJSemVja_qARLGER9n0WQ12wwfJspc-KE09huXzM7bzq_H15PCA Message-ID: To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: William Liu , netdev@vger.kernel.org, dave.taht@gmail.com, xiyou.wangcong@gmail.com, pabeni@redhat.com, kuba@kernel.org, savy@syst3mfailure.io, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, horms@kernel.org, cake@lists.bufferbloat.net Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID-Hash: E7YPLTVNABNWSBXYXPNXWJP7WMZC3G2K X-Message-ID-Hash: E7YPLTVNABNWSBXYXPNXWJP7WMZC3G2K X-MailFrom: jhs@mojatatu.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list Subject: [Cake] Re: [PATCH net v2 1/2] net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit List-Id: Cake - FQ_codel the next generation Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Tue, Aug 19, 2025 at 4:51=E2=80=AFAM Toke H=C3=B8iland-J=C3=B8rgensen wrote: > > William Liu writes: > > > The following setup can trigger a WARNING in htb_activate due to > > the condition: !cl->leaf.q->q.qlen > > > > tc qdisc del dev lo root > > tc qdisc add dev lo root handle 1: htb default 1 > > tc class add dev lo parent 1: classid 1:1 \ > > htb rate 64bit > > tc qdisc add dev lo parent 1:1 handle f: \ > > cake memlimit 1b > > ping -I lo -f -c1 -s64 -W0.001 127.0.0.1 > > > > This is because the low memlimit leads to a low buffer_limit, which > > causes packet dropping. However, cake_enqueue still returns > > NET_XMIT_SUCCESS, causing htb_enqueue to call htb_activate with an > > empty child qdisc. We should return NET_XMIT_CN when packets are > > dropped from the same tin and flow. > > > > I do not believe return value of NET_XMIT_CN is necessary for packet > > drops in the case of ack filtering, as that is meant to optimize > > performance, not to signal congestion. > > > > Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cak= e) qdisc") > > Signed-off-by: William Liu > > Reviewed-by: Savino Dicanosa > > Acked-by: Toke H=C3=B8iland-J=C3=B8rgensen Reviewed-by: Jamal Hadi Salim cheers, jamal >