-----Original Message----- From: Donald Hunter donald.hunter@gmail.com Sent: Wednesday, April 23, 2025 2:03 PM To: Chia-Yu Chang (Nokia) chia-yu.chang@nokia-bell-labs.com Cc: xandfury@gmail.com; netdev@vger.kernel.org; dave.taht@gmail.com; pabeni@redhat.com; jhs@mojatatu.com; kuba@kernel.org; stephen@networkplumber.org; xiyou.wangcong@gmail.com; jiri@resnulli.us; davem@davemloft.net; edumazet@google.com; horms@kernel.org; andrew+netdev@lunn.ch; ast@fiberby.net; liuhangbin@gmail.com; shuah@kernel.org; linux-kselftest@vger.kernel.org; ij@kernel.org; ncardwell@google.com; Koen De Schepper (Nokia) koen.de_schepper@nokia-bell-labs.com; g.white g.white@cablelabs.com; ingemar.s.johansson@ericsson.com; mirja.kuehlewind@ericsson.com; cheshire@apple.com; rs.ietf@gmx.at; Jason_Livingood@comcast.com; vidhi_goel vidhi_goel@apple.com Subject: Re: [PATCH v12 net-next 3/5] sched: Struct definition and parsing of dualpi2 qdisc
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chia-yu.chang@nokia-bell-labs.com 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;+}