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Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , Victor Nogueira , hybris , Sashiko Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID-Hash: 6PF3SKZF5HW4KUCBGRZJWGMXJKVXAYFK X-Message-ID-Hash: 6PF3SKZF5HW4KUCBGRZJWGMXJKVXAYFK X-MailFrom: edumazet@google.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-next] net/sched: fq_codel, cake: widen backlogs to u64 List-Id: Cake - FQ_codel the next generation Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Sat, Sep 26, 2026 at 11:43=E2=80=AFAM Jamal Hadi Salim 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 <=3D > 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.