[PATCH net-next v9 1/3] net/sched: sch_fq_pie: add per-flow statistics via class ops
flat view
COLD16d
From: Hemendra M. Naik <hidden>
Date: 2026-09-28 04:34:24
Also in:
linux-kselftest, lkml
Subsystem:
networking [general], tc subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
Revision v9 of 9 in this series.
Revisions (9)
FQ-PIE schedules independent PIE controllers per flow but exposes no per-flow AQM state. Without class-level statistics there is no way to observe the per-flow drop probability, queue delay, deficit or dequeue rate from userspace. Extend tc_fq_pie_xstats with a type discriminator and tc_fq_pie_cl_stats for per-flow metrics. The nine existing __u32 counters keep their offsets, type is appended at offset 36 and class_stats follows it, growing the structure from 36 to 64 bytes. Wire up fq_pie_class_ops with walk, dump, and dump_stats only so that 'tc -s class show' reports per-flow state (prob, delay, deficit, avg_dq_rate, dq_rate_estimating). Filter attachment callbacks (.tcf_block, .bind_tcf, .unbind_tcf) are omitted on purpose. Signed-off-by: Hemendra M. Naik <redacted> Signed-off-by: Vishal Kamath <redacted> Signed-off-by: Mohit P. Tahiliani <redacted> --- include/uapi/linux/pkt_sched.h | 17 +++++++ net/sched/sch_fq_pie.c | 88 +++++++++++++++++++++++++++++++++- 2 files changed, 104 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index 490efd288526..fef848eaaab2 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h@@ -953,6 +953,21 @@ enum { }; #define TCA_FQ_PIE_MAX (__TCA_FQ_PIE_MAX - 1) +enum { + TCA_FQ_PIE_XSTATS_QDISC, + TCA_FQ_PIE_XSTATS_CLASS, +}; + +struct tc_fq_pie_cl_stats { + __u64 prob; /* current probability */ + __u32 delay; /* current delay in microseconds */ + __s32 deficit; /* number of remaining byte credits */ + __u32 avg_dq_rate; /* current average dq_rate in + * bytes/second + */ + __u32 dq_rate_estimating; /* is avg_dq_rate being calculated? */ +}; + struct tc_fq_pie_xstats { __u32 packets_in; /* total number of packets enqueued */ __u32 dropped; /* packets dropped due to fq_pie_action */
@@ -963,6 +978,8 @@ struct tc_fq_pie_xstats { __u32 new_flows_len; /* count of flows in new list */ __u32 old_flows_len; /* count of flows in old list */ __u32 memory_usage; /* total memory across all queues */ + __u32 type; + struct tc_fq_pie_cl_stats class_stats; }; /* CBS */
diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index 5982847df8f8..8cd99ff40d0a 100644
--- a/net/sched/sch_fq_pie.c
+++ b/net/sched/sch_fq_pie.c@@ -511,7 +511,11 @@ static int fq_pie_dump(struct Qdisc *sch, struct sk_buff *skb) static int fq_pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d) { struct fq_pie_sched_data *q = qdisc_priv(sch); - struct tc_fq_pie_xstats st = { 0 }; + + struct tc_fq_pie_xstats st = { + .type = TCA_FQ_PIE_XSTATS_QDISC, + }; + struct list_head *pos; sch_tree_lock(sch);
@@ -563,7 +567,89 @@ static void fq_pie_destroy(struct Qdisc *sch) kvfree(q->flows); } +static struct Qdisc *fq_pie_leaf(struct Qdisc *sch, unsigned long arg) +{ + return NULL; +} + +static unsigned long fq_pie_find(struct Qdisc *sch, u32 classid) +{ + return 0; +} + +static int fq_pie_dump_class(struct Qdisc *sch, unsigned long cl, + struct sk_buff *skb, struct tcmsg *tcm) +{ + tcm->tcm_handle |= TC_H_MIN(cl); + return 0; +} + +static int fq_pie_dump_class_stats(struct Qdisc *sch, unsigned long cl, + struct gnet_dump *d) +{ + struct fq_pie_sched_data *q = qdisc_priv(sch); + struct gnet_stats_queue qs = { 0 }; + struct tc_fq_pie_xstats xstats; + u32 idx = cl - 1; + + if (idx < q->flows_cnt) { + const struct fq_pie_flow *flow = &q->flows[idx]; + + memset(&xstats, 0, sizeof(xstats)); + xstats.type = TCA_FQ_PIE_XSTATS_CLASS; + xstats.class_stats.prob = + READ_ONCE(flow->vars.prob) << BITS_PER_BYTE; + xstats.class_stats.delay = + div_u64(PSCHED_TICKS2NS(READ_ONCE(flow->vars.qdelay)), + NSEC_PER_USEC); + xstats.class_stats.deficit = READ_ONCE(flow->deficit); + xstats.class_stats.dq_rate_estimating = + READ_ONCE(q->p_params.dq_rate_estimator); + + if (xstats.class_stats.dq_rate_estimating) { + xstats.class_stats.avg_dq_rate = + ((u64)READ_ONCE(flow->vars.avg_dq_rate) + * PSCHED_TICKS_PER_SEC) >> PIE_SCALE; + } + + qs.qlen = READ_ONCE(flow->qlen); + qs.backlog = READ_ONCE(flow->backlog); + } + if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0) + return -1; + if (idx < q->flows_cnt) + return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); + return 0; +} + +static void fq_pie_walk(struct Qdisc *sch, struct qdisc_walker *arg) +{ + struct fq_pie_sched_data *q = qdisc_priv(sch); + unsigned int i; + + if (arg->stop) + return; + + for (i = 0; i < q->flows_cnt; i++) { + if (list_empty(&q->flows[i].flowchain)) { + arg->count++; + continue; + } + if (!tc_qdisc_stats_dump(sch, i + 1, arg)) + break; + } +} + +static const struct Qdisc_class_ops fq_pie_class_ops = { + .leaf = fq_pie_leaf, + .find = fq_pie_find, + .dump = fq_pie_dump_class, + .dump_stats = fq_pie_dump_class_stats, + .walk = fq_pie_walk, +}; + static struct Qdisc_ops fq_pie_qdisc_ops __read_mostly = { + .cl_ops = &fq_pie_class_ops, .id = "fq_pie", .priv_size = sizeof(struct fq_pie_sched_data), .enqueue = fq_pie_qdisc_enqueue,
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2.34.1