net/sched: sch_cake: fixup cake_mq rate adjustment for diffserv config

cake_mq's rate adjustment during the sync periods did not adjust the
rates for every tin in a diffserv config. This lead to inconsistencies
of rates between the tins. Fix this by setting the rates for all tins
during synchronization.

Fixes: 1bddd758bac2 ("net/sched: sch_cake: share shaper state across sub-instances of cake_mq")
Signed-off-by: Jonas Köppeler <j.koeppeler@tu-berlin.de>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260226-cake-mq-skip-sync-bandwidth-unlimited-v1-2-01830bb4db87@tu-berlin.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index b23fc7d9fafe53e32c1930f4ecb89e77cc280244..9efe23f8371b3c1ac1eed5df6bfdc8f97af52b4c 100644 (file)
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -391,8 +391,8 @@ static const u32 inv_sqrt_cache[REC_INV_SQRT_CACHE] = {
        1239850263, 1191209601, 1147878294, 1108955788
 };
 
-static void cake_set_rate(struct cake_tin_data *b, u64 rate, u32 mtu,
-                         u64 target_ns, u64 rtt_est_ns);
+static void cake_configure_rates(struct Qdisc *sch, u64 rate, bool rate_adjust);
+
 /* http://en.wikipedia.org/wiki/Methods_of_computing_square_roots
  * new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2)
  *
@@ -2040,12 +2040,9 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
                if (num_active_qs > 1)
                        new_rate = div64_u64(q->config->rate_bps, num_active_qs);
 
-               /* mtu = 0 is used to only update the rate and not mess with cobalt params */
-               cake_set_rate(b, new_rate, 0, 0, 0);
+               cake_configure_rates(sch, new_rate, true);
                q->last_checked_active = now;
                q->active_queues = num_active_qs;
-               q->rate_ns = b->tin_rate_ns;
-               q->rate_shft = b->tin_rate_shft;
        }
 
 begin:
@@ -2362,12 +2359,10 @@ static void cake_set_rate(struct cake_tin_data *b, u64 rate, u32 mtu,
        b->cparams.p_dec = 1 << 20; /* 1/4096 */
 }
 
-static int cake_config_besteffort(struct Qdisc *sch)
+static int cake_config_besteffort(struct Qdisc *sch, u64 rate, u32 mtu)
 {
        struct cake_sched_data *q = qdisc_priv(sch);
        struct cake_tin_data *b = &q->tins[0];
-       u32 mtu = psched_mtu(qdisc_dev(sch));
-       u64 rate = q->config->rate_bps;
 
        q->tin_cnt = 1;
 
@@ -2381,12 +2376,10 @@ static int cake_config_besteffort(struct Qdisc *sch)
        return 0;
 }
 
-static int cake_config_precedence(struct Qdisc *sch)
+static int cake_config_precedence(struct Qdisc *sch, u64 rate, u32 mtu)
 {
        /* convert high-level (user visible) parameters into internal format */
        struct cake_sched_data *q = qdisc_priv(sch);
-       u32 mtu = psched_mtu(qdisc_dev(sch));
-       u64 rate = q->config->rate_bps;
        u32 quantum = 256;
        u32 i;
 
@@ -2457,7 +2450,7 @@ static int cake_config_precedence(struct Qdisc *sch)
  *     Total 12 traffic classes.
  */
 
-static int cake_config_diffserv8(struct Qdisc *sch)
+static int cake_config_diffserv8(struct Qdisc *sch, u64 rate, u32 mtu)
 {
 /*     Pruned list of traffic classes for typical applications:
  *
@@ -2474,8 +2467,6 @@ static int cake_config_diffserv8(struct Qdisc *sch)
  */
 
        struct cake_sched_data *q = qdisc_priv(sch);
-       u32 mtu = psched_mtu(qdisc_dev(sch));
-       u64 rate = q->config->rate_bps;
        u32 quantum = 256;
        u32 i;
 
@@ -2505,7 +2496,7 @@ static int cake_config_diffserv8(struct Qdisc *sch)
        return 0;
 }
 
-static int cake_config_diffserv4(struct Qdisc *sch)
+static int cake_config_diffserv4(struct Qdisc *sch, u64 rate, u32 mtu)
 {
 /*  Further pruned list of traffic classes for four-class system:
  *
@@ -2518,8 +2509,6 @@ static int cake_config_diffserv4(struct Qdisc *sch)
  */
 
        struct cake_sched_data *q = qdisc_priv(sch);
-       u32 mtu = psched_mtu(qdisc_dev(sch));
-       u64 rate = q->config->rate_bps;
        u32 quantum = 1024;
 
        q->tin_cnt = 4;
@@ -2547,7 +2536,7 @@ static int cake_config_diffserv4(struct Qdisc *sch)
        return 0;
 }
 
-static int cake_config_diffserv3(struct Qdisc *sch)
+static int cake_config_diffserv3(struct Qdisc *sch, u64 rate, u32 mtu)
 {
 /*  Simplified Diffserv structure with 3 tins.
  *             Latency Sensitive       (CS7, CS6, EF, VA, TOS4)
@@ -2555,8 +2544,6 @@ static int cake_config_diffserv3(struct Qdisc *sch)
  *             Low Priority            (LE, CS1)
  */
        struct cake_sched_data *q = qdisc_priv(sch);
-       u32 mtu = psched_mtu(qdisc_dev(sch));
-       u64 rate = q->config->rate_bps;
        u32 quantum = 1024;
 
        q->tin_cnt = 3;
@@ -2581,32 +2568,33 @@ static int cake_config_diffserv3(struct Qdisc *sch)
        return 0;
 }
 
-static void cake_reconfigure(struct Qdisc *sch)
+static void cake_configure_rates(struct Qdisc *sch, u64 rate, bool rate_adjust)
 {
+       u32 mtu = likely(rate_adjust) ? 0 : psched_mtu(qdisc_dev(sch));
        struct cake_sched_data *qd = qdisc_priv(sch);
        struct cake_sched_config *q = qd->config;
        int c, ft;
 
        switch (q->tin_mode) {
        case CAKE_DIFFSERV_BESTEFFORT:
-               ft = cake_config_besteffort(sch);
+               ft = cake_config_besteffort(sch, rate, mtu);
                break;
 
        case CAKE_DIFFSERV_PRECEDENCE:
-               ft = cake_config_precedence(sch);
+               ft = cake_config_precedence(sch, rate, mtu);
                break;
 
        case CAKE_DIFFSERV_DIFFSERV8:
-               ft = cake_config_diffserv8(sch);
+               ft = cake_config_diffserv8(sch, rate, mtu);
                break;
 
        case CAKE_DIFFSERV_DIFFSERV4:
-               ft = cake_config_diffserv4(sch);
+               ft = cake_config_diffserv4(sch, rate, mtu);
                break;
 
        case CAKE_DIFFSERV_DIFFSERV3:
        default:
-               ft = cake_config_diffserv3(sch);
+               ft = cake_config_diffserv3(sch, rate, mtu);
                break;
        }
 
@@ -2617,6 +2605,14 @@ static void cake_reconfigure(struct Qdisc *sch)
 
        qd->rate_ns   = qd->tins[ft].tin_rate_ns;
        qd->rate_shft = qd->tins[ft].tin_rate_shft;
+}
+
+static void cake_reconfigure(struct Qdisc *sch)
+{
+       struct cake_sched_data *qd = qdisc_priv(sch);
+       struct cake_sched_config *q = qd->config;
+
+       cake_configure_rates(sch, qd->config->rate_bps, false);
 
        if (q->buffer_config_limit) {
                qd->buffer_limit = q->buffer_config_limit;