diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h index 127ac6d2888c..390efb54b2e0 100644 --- a/include/uapi/linux/pkt_sched.h +++ b/include/uapi/linux/pkt_sched.h @@ -1159,6 +1159,8 @@ enum { * [TCA_TAPRIO_ATTR_SCHED_ENTRY_INTERVAL] */ +#define TCA_TAPRIO_ATTR_FLAG_TXTIME_ASSIST 0x1 + enum { TCA_TAPRIO_ATTR_UNSPEC, TCA_TAPRIO_ATTR_PRIOMAP, /* struct tc_mqprio_qopt */ @@ -1170,6 +1172,8 @@ enum { TCA_TAPRIO_ATTR_ADMIN_SCHED, /* The admin sched, only used in dump */ TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME, /* s64 */ TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME_EXTENSION, /* s64 */ + TCA_TAPRIO_ATTR_FLAGS, /* u32 */ + TCA_TAPRIO_ATTR_TXTIME_DELAY, /* s32 */ __TCA_TAPRIO_ATTR_MAX, }; diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 6ef0cc03fdb9..078230e44471 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -21,12 +21,16 @@ #include #include #include +#include static LIST_HEAD(taprio_list); static DEFINE_SPINLOCK(taprio_list_lock); #define TAPRIO_ALL_GATES_OPEN -1 +#define FLAGS_VALID(flags) (!((flags) & ~TCA_TAPRIO_ATTR_FLAG_TXTIME_ASSIST)) +#define TXTIME_ASSIST_IS_ENABLED(flags) ((flags) & TCA_TAPRIO_ATTR_FLAG_TXTIME_ASSIST) + struct sched_entry { struct list_head list; @@ -35,6 +39,7 @@ struct sched_entry { * packet leaves after this time. */ ktime_t close_time; + ktime_t next_txtime; atomic_t budget; int index; u32 gate_mask; @@ -55,6 +60,7 @@ struct sched_gate_list { struct taprio_sched { struct Qdisc **qdiscs; struct Qdisc *root; + u32 flags; int clockid; atomic64_t picos_per_byte; /* Using picoseconds because for 10Gbps+ * speeds it's sub-nanoseconds per byte @@ -68,6 +74,7 @@ struct taprio_sched { ktime_t (*get_time)(void); struct hrtimer advance_timer; struct list_head taprio_list; + int txtime_delay; }; static ktime_t sched_base_time(const struct sched_gate_list *sched) @@ -108,6 +115,227 @@ static void switch_schedules(struct taprio_sched *q, *admin = NULL; } +/* Get how much time has been already elapsed in the current cycle. */ +static s32 get_cycle_time_elapsed(struct sched_gate_list *sched, ktime_t time) +{ + ktime_t time_since_sched_start; + s32 time_elapsed; + + time_since_sched_start = ktime_sub(time, sched->base_time); + div_s64_rem(time_since_sched_start, sched->cycle_time, &time_elapsed); + + return time_elapsed; +} + +static ktime_t get_interval_end_time(struct sched_gate_list *sched, + struct sched_gate_list *admin, + struct sched_entry *entry, + ktime_t intv_start) +{ + s32 cycle_elapsed = get_cycle_time_elapsed(sched, intv_start); + ktime_t intv_end, cycle_ext_end, cycle_end; + + cycle_end = ktime_add_ns(intv_start, sched->cycle_time - cycle_elapsed); + intv_end = ktime_add_ns(intv_start, entry->interval); + cycle_ext_end = ktime_add(cycle_end, sched->cycle_time_extension); + + if (ktime_before(intv_end, cycle_end)) + return intv_end; + else if (admin && admin != sched && + ktime_after(admin->base_time, cycle_end) && + ktime_before(admin->base_time, cycle_ext_end)) + return admin->base_time; + else + return cycle_end; +} + +static int length_to_duration(struct taprio_sched *q, int len) +{ + return div_u64(len * atomic64_read(&q->picos_per_byte), 1000); +} + +/* Returns the entry corresponding to next available interval. If + * validate_interval is set, it only validates whether the timestamp occurs + * when the gate corresponding to the skb's traffic class is open. + */ +static struct sched_entry *find_entry_to_transmit(struct sk_buff *skb, + struct Qdisc *sch, + struct sched_gate_list *sched, + struct sched_gate_list *admin, + ktime_t time, + ktime_t *interval_start, + ktime_t *interval_end, + bool validate_interval) +{ + ktime_t curr_intv_start, curr_intv_end, cycle_end, packet_transmit_time; + ktime_t earliest_txtime = KTIME_MAX, txtime, cycle, transmit_end_time; + struct sched_entry *entry = NULL, *entry_found = NULL; + struct taprio_sched *q = qdisc_priv(sch); + struct net_device *dev = qdisc_dev(sch); + bool entry_available = false; + s32 cycle_elapsed; + int tc, n; + + tc = netdev_get_prio_tc_map(dev, skb->priority); + packet_transmit_time = length_to_duration(q, qdisc_pkt_len(skb)); + + *interval_start = 0; + *interval_end = 0; + + if (!sched) + return NULL; + + cycle = sched->cycle_time; + cycle_elapsed = get_cycle_time_elapsed(sched, time); + curr_intv_end = ktime_sub_ns(time, cycle_elapsed); + cycle_end = ktime_add_ns(curr_intv_end, cycle); + + list_for_each_entry(entry, &sched->entries, list) { + curr_intv_start = curr_intv_end; + curr_intv_end = get_interval_end_time(sched, admin, entry, + curr_intv_start); + + if (ktime_after(curr_intv_start, cycle_end)) + break; + + if (!(entry->gate_mask & BIT(tc)) || + packet_transmit_time > entry->interval) + continue; + + txtime = entry->next_txtime; + + if (ktime_before(txtime, time) || validate_interval) { + transmit_end_time = ktime_add_ns(time, packet_transmit_time); + if ((ktime_before(curr_intv_start, time) && + ktime_before(transmit_end_time, curr_intv_end)) || + (ktime_after(curr_intv_start, time) && !validate_interval)) { + entry_found = entry; + *interval_start = curr_intv_start; + *interval_end = curr_intv_end; + break; + } else if (!entry_available && !validate_interval) { + /* Here, we are just trying to find out the + * first available interval in the next cycle. + */ + entry_available = 1; + entry_found = entry; + *interval_start = ktime_add_ns(curr_intv_start, cycle); + *interval_end = ktime_add_ns(curr_intv_end, cycle); + } + } else if (ktime_before(txtime, earliest_txtime) && + !entry_available) { + earliest_txtime = txtime; + entry_found = entry; + n = div_s64(ktime_sub(txtime, curr_intv_start), cycle); + *interval_start = ktime_add(curr_intv_start, n * cycle); + *interval_end = ktime_add(curr_intv_end, n * cycle); + } + } + + return entry_found; +} + +static bool is_valid_interval(struct sk_buff *skb, struct Qdisc *sch) +{ + struct taprio_sched *q = qdisc_priv(sch); + struct sched_gate_list *sched, *admin; + ktime_t interval_start, interval_end; + struct sched_entry *entry; + + rcu_read_lock(); + sched = rcu_dereference(q->oper_sched); + admin = rcu_dereference(q->admin_sched); + + entry = find_entry_to_transmit(skb, sch, sched, admin, skb->tstamp, + &interval_start, &interval_end, true); + rcu_read_unlock(); + + return entry; +} + +/* There are a few scenarios where we will have to modify the txtime from + * what is read from next_txtime in sched_entry. They are: + * 1. If txtime is in the past, + * a. The gate for the traffic class is currently open and packet can be + * transmitted before it closes, schedule the packet right away. + * b. If the gate corresponding to the traffic class is going to open later + * in the cycle, set the txtime of packet to the interval start. + * 2. If txtime is in the future, there are packets corresponding to the + * current traffic class waiting to be transmitted. So, the following + * possibilities exist: + * a. We can transmit the packet before the window containing the txtime + * closes. + * b. The window might close before the transmission can be completed + * successfully. So, schedule the packet in the next open window. + */ +static long get_packet_txtime(struct sk_buff *skb, struct Qdisc *sch) +{ + ktime_t transmit_end_time, interval_end, interval_start; + struct taprio_sched *q = qdisc_priv(sch); + struct sched_gate_list *sched, *admin; + ktime_t minimum_time, now, txtime; + int len, packet_transmit_time; + struct sched_entry *entry; + bool sched_changed; + + now = q->get_time(); + minimum_time = ktime_add_ns(now, q->txtime_delay); + + rcu_read_lock(); + admin = rcu_dereference(q->admin_sched); + sched = rcu_dereference(q->oper_sched); + if (admin && ktime_after(minimum_time, admin->base_time)) + switch_schedules(q, &admin, &sched); + + /* Until the schedule starts, all the queues are open */ + if (!sched || ktime_before(minimum_time, sched->base_time)) { + txtime = minimum_time; + goto done; + } + + len = qdisc_pkt_len(skb); + packet_transmit_time = length_to_duration(q, len); + + do { + sched_changed = 0; + + entry = find_entry_to_transmit(skb, sch, sched, admin, + minimum_time, + &interval_start, &interval_end, + false); + if (!entry) { + txtime = 0; + goto done; + } + + txtime = entry->next_txtime; + txtime = max_t(ktime_t, txtime, minimum_time); + txtime = max_t(ktime_t, txtime, interval_start); + + if (admin && admin != sched && + ktime_after(txtime, admin->base_time)) { + sched = admin; + sched_changed = 1; + continue; + } + + transmit_end_time = ktime_add(txtime, packet_transmit_time); + minimum_time = transmit_end_time; + + /* Update the txtime of current entry to the next time it's + * interval starts. + */ + if (ktime_after(transmit_end_time, interval_end)) + entry->next_txtime = ktime_add(interval_start, sched->cycle_time); + } while (sched_changed || ktime_after(transmit_end_time, interval_end)); + + entry->next_txtime = transmit_end_time; + +done: + rcu_read_unlock(); + return txtime; +} + static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { @@ -121,6 +349,15 @@ static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch, if (unlikely(!child)) return qdisc_drop(skb, sch, to_free); + if (skb->sk && sock_flag(skb->sk, SOCK_TXTIME)) { + if (!is_valid_interval(skb, sch)) + return qdisc_drop(skb, sch, to_free); + } else if (TXTIME_ASSIST_IS_ENABLED(q->flags)) { + skb->tstamp = get_packet_txtime(skb, sch); + if (!skb->tstamp) + return qdisc_drop(skb, sch, to_free); + } + qdisc_qstats_backlog_inc(sch, skb); sch->q.qlen++; @@ -156,6 +393,9 @@ static struct sk_buff *taprio_peek(struct Qdisc *sch) if (!skb) continue; + if (TXTIME_ASSIST_IS_ENABLED(q->flags)) + return skb; + prio = skb->priority; tc = netdev_get_prio_tc_map(dev, prio); @@ -168,11 +408,6 @@ static struct sk_buff *taprio_peek(struct Qdisc *sch) return NULL; } -static int length_to_duration(struct taprio_sched *q, int len) -{ - return div_u64(len * atomic64_read(&q->picos_per_byte), 1000); -} - static void taprio_set_budget(struct taprio_sched *q, struct sched_entry *entry) { atomic_set(&entry->budget, @@ -216,6 +451,13 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch) if (unlikely(!child)) continue; + if (TXTIME_ASSIST_IS_ENABLED(q->flags)) { + skb = child->ops->dequeue(child); + if (!skb) + continue; + goto skb_found; + } + skb = child->ops->peek(child); if (!skb) continue; @@ -246,6 +488,7 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch) if (unlikely(!skb)) goto done; +skb_found: qdisc_bstats_update(sch, skb); qdisc_qstats_backlog_dec(sch, skb); sch->q.qlen--; @@ -522,7 +765,8 @@ static int parse_taprio_schedule(struct nlattr **tb, static int taprio_parse_mqprio_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt, - struct netlink_ext_ack *extack) + struct netlink_ext_ack *extack, + u32 taprio_flags) { int i, j; @@ -570,6 +814,9 @@ static int taprio_parse_mqprio_opt(struct net_device *dev, return -EINVAL; } + if (TXTIME_ASSIST_IS_ENABLED(taprio_flags)) + continue; + /* Verify that the offset and counts do not overlap */ for (j = i + 1; j < qopt->num_tc; j++) { if (last > qopt->offset[j]) { @@ -700,6 +947,18 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event, return NOTIFY_DONE; } +static void setup_txtime(struct taprio_sched *q, + struct sched_gate_list *sched, ktime_t base) +{ + struct sched_entry *entry; + u32 interval = 0; + + list_for_each_entry(entry, &sched->entries, list) { + entry->next_txtime = ktime_add_ns(base, interval); + interval += entry->interval; + } +} + static int taprio_change(struct Qdisc *sch, struct nlattr *opt, struct netlink_ext_ack *extack) { @@ -708,6 +967,7 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, struct taprio_sched *q = qdisc_priv(sch); struct net_device *dev = qdisc_dev(sch); struct tc_mqprio_qopt *mqprio = NULL; + u32 taprio_flags = 0; int i, err, clockid; unsigned long flags; ktime_t start; @@ -720,7 +980,21 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, if (tb[TCA_TAPRIO_ATTR_PRIOMAP]) mqprio = nla_data(tb[TCA_TAPRIO_ATTR_PRIOMAP]); - err = taprio_parse_mqprio_opt(dev, mqprio, extack); + if (tb[TCA_TAPRIO_ATTR_FLAGS]) { + taprio_flags = nla_get_u32(tb[TCA_TAPRIO_ATTR_FLAGS]); + + if (q->flags != 0 && q->flags != taprio_flags) { + NL_SET_ERR_MSG_MOD(extack, "Changing 'flags' of a running schedule is not supported"); + return -EOPNOTSUPP; + } else if (!FLAGS_VALID(taprio_flags)) { + NL_SET_ERR_MSG_MOD(extack, "Specified 'flags' are not valid"); + return -EINVAL; + } + + q->flags = taprio_flags; + } + + err = taprio_parse_mqprio_opt(dev, mqprio, extack, taprio_flags); if (err < 0) return err; @@ -779,7 +1053,18 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, /* Protects against enqueue()/dequeue() */ spin_lock_bh(qdisc_lock(sch)); - if (!hrtimer_active(&q->advance_timer)) { + if (tb[TCA_TAPRIO_ATTR_TXTIME_DELAY]) { + if (!TXTIME_ASSIST_IS_ENABLED(q->flags)) { + NL_SET_ERR_MSG_MOD(extack, "txtime-delay can only be set when txtime-assist mode is enabled"); + err = -EINVAL; + goto unlock; + } + + q->txtime_delay = nla_get_s32(tb[TCA_TAPRIO_ATTR_TXTIME_DELAY]); + } + + if (!TXTIME_ASSIST_IS_ENABLED(taprio_flags) && + !hrtimer_active(&q->advance_timer)) { hrtimer_init(&q->advance_timer, q->clockid, HRTIMER_MODE_ABS); q->advance_timer.function = advance_sched; } @@ -822,20 +1107,35 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, goto unlock; } - setup_first_close_time(q, new_admin, start); + if (TXTIME_ASSIST_IS_ENABLED(taprio_flags)) { + setup_txtime(q, new_admin, start); - /* Protects against advance_sched() */ - spin_lock_irqsave(&q->current_entry_lock, flags); + if (!oper) { + rcu_assign_pointer(q->oper_sched, new_admin); + err = 0; + new_admin = NULL; + goto unlock; + } - taprio_start_sched(sch, start, new_admin); + rcu_assign_pointer(q->admin_sched, new_admin); + if (admin) + call_rcu(&admin->rcu, taprio_free_sched_cb); + } else { + setup_first_close_time(q, new_admin, start); + + /* Protects against advance_sched() */ + spin_lock_irqsave(&q->current_entry_lock, flags); + + taprio_start_sched(sch, start, new_admin); + + rcu_assign_pointer(q->admin_sched, new_admin); + if (admin) + call_rcu(&admin->rcu, taprio_free_sched_cb); + + spin_unlock_irqrestore(&q->current_entry_lock, flags); + } - rcu_assign_pointer(q->admin_sched, new_admin); - if (admin) - call_rcu(&admin->rcu, taprio_free_sched_cb); new_admin = NULL; - - spin_unlock_irqrestore(&q->current_entry_lock, flags); - err = 0; unlock: @@ -1073,6 +1373,13 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) if (nla_put_s32(skb, TCA_TAPRIO_ATTR_SCHED_CLOCKID, q->clockid)) goto options_error; + if (q->flags && nla_put_u32(skb, TCA_TAPRIO_ATTR_FLAGS, q->flags)) + goto options_error; + + if (q->txtime_delay && + nla_put_s32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, q->txtime_delay)) + goto options_error; + if (oper && dump_schedule(skb, oper)) goto options_error;