From: Eric Dumazet <edumazet@google.com>
To: Jamal Hadi Salim <hadi@mojatatu.com>
Cc: "Sebastian Moeller" <moeller0@gmx.de>,
"Jamal Hadi Salim" <jhs@mojatatu.com>,
netdev@vger.kernel.org, "Toke Høiland-Jørgensen" <toke@toke.dk>,
cake@lists.bufferbloat.net, "Jiri Pirko" <jiri@resnulli.us>,
"David S . Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Victor Nogueira" <victor@mojatatu.com>,
hybris <hybris@mojatatu.ai>, Sashiko <sashiko-bot@kernel.org>
Subject: [Cake] Re: [PATCH net-next] net/sched: fq_codel, cake: widen backlogs to u64
Date: Sat, 26 Sep 2026 11:48:49 +0200 [thread overview]
Message-ID: <CANn89i+GOFH_8g+vSV0jUj0aBqLYVWuFOrHuDggZu9kPC_m6tQ@mail.gmail.com> (raw)
In-Reply-To: <CAAFAkD_U8PGfdJAgSLsh3ku+tTBvQYB012k7jEUacfm6HothyQ@mail.gmail.com>
On Sat, Sep 26, 2026 at 11:43 AM Jamal Hadi Salim <hadi@mojatatu.com> wrote:
> I am working on a v2 that drops at enqueue once the accounted backlog
> crosses (U32_MAX - QDISC_PKT_LEN_MAX), so no counter can wrap.
> That is Eric's original suggestion which preserves the point you raised.
>
> While looking at this closely for this update i noticed more qdiscs
> which for different reasons also suffer from ((u64)backlog + len <=
> limit idiom.
> So far it's clear from bfifo, gred and plug are the only ones safe
> because their limit is in bytes (as opposed to others which are packet
> counting)
>
> Eric: Unless i hear otherwise from you, the configurable byte ceiling
> you mentioned (a good noun seems to be CONFIG_NET_SCH_BACKLOG_CEILING)
> is a follow-up;
SGTM, thanks Jamal.
prev parent reply other threads:[~2026-09-26 9:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-25 8:53 [Cake] [PATCH net-next] net/sched: fq_codel, cake: widen backlogs to u64 Jamal Hadi Salim
2026-09-25 9:12 ` [Cake] " Eric Dumazet
2026-09-25 11:27 ` Jamal Hadi Salim
2026-09-25 12:22 ` Jamal Hadi Salim
2026-09-25 13:03 ` Eric Dumazet
2026-09-25 13:30 ` Sebastian Moeller
2026-09-25 13:43 ` Eric Dumazet
2026-09-25 14:02 ` Sebastian Moeller
[not found] ` <CAAFAkD_U8PGfdJAgSLsh3ku+tTBvQYB012k7jEUacfm6HothyQ@mail.gmail.com>
2026-09-26 9:48 ` Eric Dumazet [this message]
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