[PATCH v2 net 1/7] net/sched: taprio: fix too early schedules switching
From: Faizal Rahim <hidden>
Date: 2023-11-07 11:22:03
Also in:
lkml
Subsystem:
cbs/etf/taprio qdiscs, networking [general], tc subsystem, the rest · Maintainers:
Vinicius Costa Gomes, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
In the current taprio code for dynamic schedule change,
admin/oper schedule switching happens immediately when
should_change_schedules() is true. Then the last entry of
the old admin schedule stops being valid anymore from
taprio_dequeue_from_txq’s perspective.
To solve this, we have to delay the switch_schedules() call via
the new cycle_time_correction variable. The variable serves 2
purposes:
1. Upon entering advance_sched(), if the value is set to a
non-initialized value, it indicates that we need to change
schedule.
2. Store the cycle time correction value which will be used for
negative or positive correction.
Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule")
Signed-off-by: Faizal Rahim <redacted>
---
net/sched/sch_taprio.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 2e1949de4171..dee103647823 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c@@ -41,6 +41,7 @@ static struct static_key_false taprio_have_working_mqprio; #define TXTIME_ASSIST_IS_ENABLED(flags) ((flags) & TCA_TAPRIO_ATTR_FLAG_TXTIME_ASSIST) #define FULL_OFFLOAD_IS_ENABLED(flags) ((flags) & TCA_TAPRIO_ATTR_FLAG_FULL_OFFLOAD) #define TAPRIO_FLAGS_INVALID U32_MAX +#define INIT_CYCLE_TIME_CORRECTION S64_MIN struct sched_entry { /* Durations between this GCL entry and the GCL entry where the
@@ -75,6 +76,7 @@ struct sched_gate_list { ktime_t cycle_end_time; s64 cycle_time; s64 cycle_time_extension; + s64 cycle_time_correction; s64 base_time; };
@@ -940,8 +942,10 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer) admin = rcu_dereference_protected(q->admin_sched, lockdep_is_held(&q->current_entry_lock)); - if (!oper) + if (!oper || oper->cycle_time_correction != INIT_CYCLE_TIME_CORRECTION) { + oper->cycle_time_correction = INIT_CYCLE_TIME_CORRECTION; switch_schedules(q, &admin, &oper); + } /* This can happen in two cases: 1. this is the very first run * of this function (i.e. we weren't running any schedule
@@ -981,7 +985,7 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer) * schedule runs. */ end_time = sched_base_time(admin); - switch_schedules(q, &admin, &oper); + oper->cycle_time_correction = 0; } next->end_time = end_time;
@@ -1174,6 +1178,7 @@ static int parse_taprio_schedule(struct taprio_sched *q, struct nlattr **tb, } taprio_calculate_gate_durations(q, new); + new->cycle_time_correction = INIT_CYCLE_TIME_CORRECTION; return 0; }
--
2.25.1