> -----Original Message-----
> From: Donald Hunter <[email protected]>
> Sent: Wednesday, April 23, 2025 2:03 PM
> To: Chia-Yu Chang (Nokia) <[email protected]>
> Cc: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; Koen De Schepper (Nokia)
> <[email protected]>; g.white <[email protected]>;
> [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; vidhi_goel
> <[email protected]>
> Subject: Re: [PATCH v12 net-next 3/5] sched: Struct definition and parsing of
> dualpi2 qdisc
>
>
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>
> [email protected] writes:
>
> > +
> > +static const struct nla_policy dualpi2_policy[TCA_DUALPI2_MAX + 1] = {
> > + [TCA_DUALPI2_LIMIT] = NLA_POLICY_MIN(NLA_U32, 1),
> > + [TCA_DUALPI2_MEMORY_LIMIT] = NLA_POLICY_MIN(NLA_U32, 1),
> > + [TCA_DUALPI2_TARGET] = {.type = NLA_U32},
> > + [TCA_DUALPI2_TUPDATE] = NLA_POLICY_MIN(NLA_U32, 1),
> > + [TCA_DUALPI2_ALPHA] =
> > + NLA_POLICY_FULL_RANGE(NLA_U32, &dualpi2_alpha_beta_range),
> > + [TCA_DUALPI2_BETA] =
> > + NLA_POLICY_FULL_RANGE(NLA_U32, &dualpi2_alpha_beta_range),
> > + [TCA_DUALPI2_STEP_THRESH] = {.type = NLA_U32},
> > + [TCA_DUALPI2_STEP_PACKETS] = {.type = NLA_U8},
> > + [TCA_DUALPI2_MIN_QLEN_STEP] = {.type = NLA_U32},
> > + [TCA_DUALPI2_COUPLING] = NLA_POLICY_MIN(NLA_U8, 1),
> > + [TCA_DUALPI2_DROP_OVERLOAD] = {.type = NLA_U8},
> > + [TCA_DUALPI2_DROP_EARLY] = {.type = NLA_U8},
> > + [TCA_DUALPI2_C_PROTECTION] =
> > + NLA_POLICY_FULL_RANGE(NLA_U8, &dualpi2_wc_range),
> > + [TCA_DUALPI2_ECN_MASK] = {.type = NLA_U8},
> > + [TCA_DUALPI2_SPLIT_GSO] = {.type = NLA_U8},
> > +};
> > +
> > +static int dualpi2_change(struct Qdisc *sch, struct nlattr *opt,
> > + struct netlink_ext_ack *extack) {
> > + struct nlattr *tb[TCA_DUALPI2_MAX + 1];
> > + struct dualpi2_sched_data *q;
> > + int old_backlog;
> > + int old_qlen;
> > + int err;
> > +
> > + if (!opt)
> > + return -EINVAL;
> > + err = nla_parse_nested(tb, TCA_DUALPI2_MAX, opt, dualpi2_policy,
> > + extack);
> > + if (err < 0)
> > + return err;
> > +
> > + q = qdisc_priv(sch);
> > + sch_tree_lock(sch);
> > +
> > + if (tb[TCA_DUALPI2_LIMIT]) {
> > + u32 limit = nla_get_u32(tb[TCA_DUALPI2_LIMIT]);
> > +
> > + WRITE_ONCE(sch->limit, limit);
> > + WRITE_ONCE(q->memory_limit, get_memory_limit(sch, limit));
> > + }
> > +
> > + if (tb[TCA_DUALPI2_MEMORY_LIMIT])
> > + WRITE_ONCE(q->memory_limit,
> > + nla_get_u32(tb[TCA_DUALPI2_MEMORY_LIMIT]));
> > +
> > + if (tb[TCA_DUALPI2_TARGET]) {
> > + u64 target = nla_get_u32(tb[TCA_DUALPI2_TARGET]);
> > +
> > + WRITE_ONCE(q->pi2_target, target * NSEC_PER_USEC);
> > + }
> > +
> > + if (tb[TCA_DUALPI2_TUPDATE]) {
> > + u64 tupdate = nla_get_u32(tb[TCA_DUALPI2_TUPDATE]);
> > +
> > + WRITE_ONCE(q->pi2_tupdate, tupdate * NSEC_PER_USEC);
> > + }
> > +
> > + if (tb[TCA_DUALPI2_ALPHA]) {
> > + u32 alpha = nla_get_u32(tb[TCA_DUALPI2_ALPHA]);
> > +
> > + WRITE_ONCE(q->pi2_alpha, dualpi2_scale_alpha_beta(alpha));
> > + }
> > +
> > + if (tb[TCA_DUALPI2_BETA]) {
> > + u32 beta = nla_get_u32(tb[TCA_DUALPI2_BETA]);
> > +
> > + WRITE_ONCE(q->pi2_beta, dualpi2_scale_alpha_beta(beta));
> > + }
> > +
> > + if (tb[TCA_DUALPI2_STEP_PACKETS]) {
> > + bool step_pkt =
> > + !!nla_get_u8(tb[TCA_DUALPI2_STEP_PACKETS]);
>
> Would it be better to define TCA_DUALPI2_STEP_PACKETS as type NLA_FLAG to
> avoid the u8 to bool conversion?
Hi Donald,
Thank you for your feedback.
After reviewing their features, I would think only TCA_DUALPI2_STEP_PACKETS as
NLA_FLAGS.
Because the other three attributes will need the ternary-state logic: (1)
Change to state A, (2) change to state B, or (3) stay in the current state.
Best regards,
Chia-Yu
>
> > + u32 step_th = READ_ONCE(q->step_thresh);
> > +
> > + WRITE_ONCE(q->step_in_packets, step_pkt);
> > + WRITE_ONCE(q->step_thresh,
> > + step_pkt ? step_th : (step_th * NSEC_PER_USEC));
> > + }
> > +
> > + if (tb[TCA_DUALPI2_STEP_THRESH]) {
> > + u32 step_th = nla_get_u32(tb[TCA_DUALPI2_STEP_THRESH]);
> > + bool step_pkt = READ_ONCE(q->step_in_packets);
> > +
> > + WRITE_ONCE(q->step_thresh,
> > + step_pkt ? step_th : (step_th * NSEC_PER_USEC));
> > + }
> > +
> > + if (tb[TCA_DUALPI2_MIN_QLEN_STEP])
> > + WRITE_ONCE(q->min_qlen_step,
> > + nla_get_u32(tb[TCA_DUALPI2_MIN_QLEN_STEP]));
> > +
> > + if (tb[TCA_DUALPI2_COUPLING]) {
> > + u8 coupling = nla_get_u8(tb[TCA_DUALPI2_COUPLING]);
> > +
> > + WRITE_ONCE(q->coupling_factor, coupling);
> > + }
> > +
> > + if (tb[TCA_DUALPI2_DROP_OVERLOAD])
> > + WRITE_ONCE(q->drop_overload,
> > + !!nla_get_u8(tb[TCA_DUALPI2_DROP_OVERLOAD]));
>
> Type NLA_FLAG?
>
> > +
> > + if (tb[TCA_DUALPI2_DROP_EARLY])
> > + WRITE_ONCE(q->drop_early,
> > + !!nla_get_u8(tb[TCA_DUALPI2_DROP_EARLY]));
>
> Type NLA_FLAG?
>
> > +
> > + if (tb[TCA_DUALPI2_C_PROTECTION]) {
> > + u8 wc = nla_get_u8(tb[TCA_DUALPI2_C_PROTECTION]);
> > +
> > + dualpi2_calculate_c_protection(sch, q, wc);
> > + }
> > +
> > + if (tb[TCA_DUALPI2_ECN_MASK])
> > + WRITE_ONCE(q->ecn_mask,
> > + nla_get_u8(tb[TCA_DUALPI2_ECN_MASK]));
> > +
> > + if (tb[TCA_DUALPI2_SPLIT_GSO])
> > + WRITE_ONCE(q->split_gso,
> > + !!nla_get_u8(tb[TCA_DUALPI2_SPLIT_GSO]));
>
> Type NLA_FLAG?
>
> > +
> > + old_qlen = qdisc_qlen(sch);
> > + old_backlog = sch->qstats.backlog;
> > + while (qdisc_qlen(sch) > sch->limit ||
> > + q->memory_used > q->memory_limit) {
> > + struct sk_buff *skb = __qdisc_dequeue_head(&sch->q);
> > +
> > + q->memory_used -= skb->truesize;
> > + qdisc_qstats_backlog_dec(sch, skb);
> > + rtnl_qdisc_drop(skb, sch);
> > + }
> > + qdisc_tree_reduce_backlog(sch, old_qlen - qdisc_qlen(sch),
> > + old_backlog - sch->qstats.backlog);
> > +
> > + sch_tree_unlock(sch);
> > + return 0;
> > +}
