From: Felix Fietkau Date: Sun, 19 Jun 2022 23:13:05 +0200 Subject: [PATCH] mac80211: switch airtime fairness back to deficit round-robin scheduling This reverts commits 6a789ba679d652587532cec2a0e0274fda172f3b and 2433647bc8d983a543e7d31b41ca2de1c7e2c198. The virtual time scheduler code has a number of issues: - queues slowed down by hardware/firmware powersave handling were not properly handled. - on ath10k in push-pull mode, tx queues that the driver tries to pull from were starved, causing excessive latency - delay between tx enqueue and reported airtime use were causing excessively bursty tx behavior The bursty behavior may also be present on the round-robin scheduler, but there it is much easier to fix without introducing additional regressions Signed-off-by: Felix Fietkau --- --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -6666,6 +6666,9 @@ static inline void ieee80211_txq_schedul { } +void __ieee80211_schedule_txq(struct ieee80211_hw *hw, + struct ieee80211_txq *txq, bool force); + /** * ieee80211_schedule_txq - schedule a TXQ for transmission * @@ -6678,7 +6681,11 @@ static inline void ieee80211_txq_schedul * The driver may call this function if it has buffered packets for * this TXQ internally. */ -void ieee80211_schedule_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq); +static inline void +ieee80211_schedule_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq) +{ + __ieee80211_schedule_txq(hw, txq, true); +} /** * ieee80211_return_txq - return a TXQ previously acquired by ieee80211_next_txq() @@ -6690,8 +6697,12 @@ void ieee80211_schedule_txq(struct ieee8 * The driver may set force=true if it has buffered packets for this TXQ * internally. */ -void ieee80211_return_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq, - bool force); +static inline void +ieee80211_return_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq, + bool force) +{ + __ieee80211_schedule_txq(hw, txq, force); +} /** * ieee80211_txq_may_transmit - check whether TXQ is allowed to transmit --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -1554,38 +1554,6 @@ static void sta_apply_mesh_params(struct #endif } -static void sta_apply_airtime_params(struct ieee80211_local *local, - struct sta_info *sta, - struct station_parameters *params) -{ - u8 ac; - - for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { - struct airtime_sched_info *air_sched = &local->airtime[ac]; - struct airtime_info *air_info = &sta->airtime[ac]; - struct txq_info *txqi; - u8 tid; - - spin_lock_bh(&air_sched->lock); - for (tid = 0; tid < IEEE80211_NUM_TIDS + 1; tid++) { - if (air_info->weight == params->airtime_weight || - !sta->sta.txq[tid] || - ac != ieee80211_ac_from_tid(tid)) - continue; - - airtime_weight_set(air_info, params->airtime_weight); - - txqi = to_txq_info(sta->sta.txq[tid]); - if (RB_EMPTY_NODE(&txqi->schedule_order)) - continue; - - ieee80211_update_airtime_weight(local, air_sched, - 0, true); - } - spin_unlock_bh(&air_sched->lock); - } -} - static int sta_apply_parameters(struct ieee80211_local *local, struct sta_info *sta, struct station_parameters *params) @@ -1773,8 +1741,7 @@ static int sta_apply_parameters(struct i sta_apply_mesh_params(local, sta, params); if (params->airtime_weight) - sta_apply_airtime_params(local, sta, params); - + sta->airtime_weight = params->airtime_weight; /* set the STA state after all sta info from usermode has been set */ if (test_sta_flag(sta, WLAN_STA_TDLS_PEER) || --- a/net/mac80211/debugfs.c +++ b/net/mac80211/debugfs.c @@ -216,14 +216,14 @@ static ssize_t aql_txq_limit_read(struct "VI %u %u\n" "BE %u %u\n" "BK %u %u\n", - local->airtime[IEEE80211_AC_VO].aql_txq_limit_low, - local->airtime[IEEE80211_AC_VO].aql_txq_limit_high, - local->airtime[IEEE80211_AC_VI].aql_txq_limit_low, - local->airtime[IEEE80211_AC_VI].aql_txq_limit_high, - local->airtime[IEEE80211_AC_BE].aql_txq_limit_low, - local->airtime[IEEE80211_AC_BE].aql_txq_limit_high, - local->airtime[IEEE80211_AC_BK].aql_txq_limit_low, - local->airtime[IEEE80211_AC_BK].aql_txq_limit_high); + local->aql_txq_limit_low[IEEE80211_AC_VO], + local->aql_txq_limit_high[IEEE80211_AC_VO], + local->aql_txq_limit_low[IEEE80211_AC_VI], + local->aql_txq_limit_high[IEEE80211_AC_VI], + local->aql_txq_limit_low[IEEE80211_AC_BE], + local->aql_txq_limit_high[IEEE80211_AC_BE], + local->aql_txq_limit_low[IEEE80211_AC_BK], + local->aql_txq_limit_high[IEEE80211_AC_BK]); return simple_read_from_buffer(user_buf, count, ppos, buf, len); } @@ -255,11 +255,11 @@ static ssize_t aql_txq_limit_write(struc if (ac >= IEEE80211_NUM_ACS) return -EINVAL; - q_limit_low_old = local->airtime[ac].aql_txq_limit_low; - q_limit_high_old = local->airtime[ac].aql_txq_limit_high; + q_limit_low_old = local->aql_txq_limit_low[ac]; + q_limit_high_old = local->aql_txq_limit_high[ac]; - local->airtime[ac].aql_txq_limit_low = q_limit_low; - local->airtime[ac].aql_txq_limit_high = q_limit_high; + local->aql_txq_limit_low[ac] = q_limit_low; + local->aql_txq_limit_high[ac] = q_limit_high; mutex_lock(&local->sta_mtx); list_for_each_entry(sta, &local->sta_list, list) { @@ -382,46 +382,6 @@ static const struct file_operations forc .llseek = default_llseek, }; -static ssize_t airtime_read(struct file *file, - char __user *user_buf, - size_t count, - loff_t *ppos) -{ - struct ieee80211_local *local = file->private_data; - char buf[200]; - u64 v_t[IEEE80211_NUM_ACS]; - u64 wt[IEEE80211_NUM_ACS]; - int len = 0, ac; - - for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { - spin_lock_bh(&local->airtime[ac].lock); - v_t[ac] = local->airtime[ac].v_t; - wt[ac] = local->airtime[ac].weight_sum; - spin_unlock_bh(&local->airtime[ac].lock); - } - len = scnprintf(buf, sizeof(buf), - "\tVO VI BE BK\n" - "Virt-t\t%-10llu %-10llu %-10llu %-10llu\n" - "Weight\t%-10llu %-10llu %-10llu %-10llu\n", - v_t[0], - v_t[1], - v_t[2], - v_t[3], - wt[0], - wt[1], - wt[2], - wt[3]); - - return simple_read_from_buffer(user_buf, count, ppos, - buf, len); -} - -static const struct file_operations airtime_ops = { - .read = airtime_read, - .open = simple_open, - .llseek = default_llseek, -}; - #ifdef CONFIG_PM static ssize_t reset_write(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) @@ -672,11 +632,7 @@ void debugfs_hw_add(struct ieee80211_loc if (local->ops->wake_tx_queue) DEBUGFS_ADD_MODE(aqm, 0600); - if (wiphy_ext_feature_isset(local->hw.wiphy, - NL80211_EXT_FEATURE_AIRTIME_FAIRNESS)) { - DEBUGFS_ADD_MODE(airtime, 0600); - DEBUGFS_ADD_MODE(airtime_flags, 0600); - } + DEBUGFS_ADD_MODE(airtime_flags, 0600); DEBUGFS_ADD(aql_txq_limit); debugfs_create_u32("aql_threshold", 0600, --- a/net/mac80211/debugfs_netdev.c +++ b/net/mac80211/debugfs_netdev.c @@ -512,34 +512,6 @@ static ssize_t ieee80211_if_fmt_aqm( } IEEE80211_IF_FILE_R(aqm); -static ssize_t ieee80211_if_fmt_airtime( - const struct ieee80211_sub_if_data *sdata, char *buf, int buflen) -{ - struct ieee80211_local *local = sdata->local; - struct ieee80211_txq *txq = sdata->vif.txq; - struct airtime_info *air_info; - int len; - - if (!txq) - return 0; - - spin_lock_bh(&local->airtime[txq->ac].lock); - air_info = to_airtime_info(txq); - len = scnprintf(buf, - buflen, - "RX: %llu us\nTX: %llu us\nWeight: %u\n" - "Virt-T: %lld us\n", - air_info->rx_airtime, - air_info->tx_airtime, - air_info->weight, - air_info->v_t); - spin_unlock_bh(&local->airtime[txq->ac].lock); - - return len; -} - -IEEE80211_IF_FILE_R(airtime); - IEEE80211_IF_FILE(multicast_to_unicast, u.ap.multicast_to_unicast, HEX); /* IBSS attributes */ @@ -685,10 +657,8 @@ static void add_common_files(struct ieee if (sdata->local->ops->wake_tx_queue && sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE && - sdata->vif.type != NL80211_IFTYPE_NAN) { + sdata->vif.type != NL80211_IFTYPE_NAN) DEBUGFS_ADD(aqm); - DEBUGFS_ADD(airtime); - } } static void add_sta_files(struct ieee80211_sub_if_data *sdata) --- a/net/mac80211/debugfs_sta.c +++ b/net/mac80211/debugfs_sta.c @@ -202,7 +202,7 @@ static ssize_t sta_airtime_read(struct f size_t bufsz = 400; char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf; u64 rx_airtime = 0, tx_airtime = 0; - u64 v_t[IEEE80211_NUM_ACS]; + s64 deficit[IEEE80211_NUM_ACS]; ssize_t rv; int ac; @@ -210,18 +210,18 @@ static ssize_t sta_airtime_read(struct f return -ENOMEM; for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { - spin_lock_bh(&local->airtime[ac].lock); + spin_lock_bh(&local->active_txq_lock[ac]); rx_airtime += sta->airtime[ac].rx_airtime; tx_airtime += sta->airtime[ac].tx_airtime; - v_t[ac] = sta->airtime[ac].v_t; - spin_unlock_bh(&local->airtime[ac].lock); + deficit[ac] = sta->airtime[ac].deficit; + spin_unlock_bh(&local->active_txq_lock[ac]); } p += scnprintf(p, bufsz + buf - p, "RX: %llu us\nTX: %llu us\nWeight: %u\n" - "Virt-T: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n", - rx_airtime, tx_airtime, sta->airtime[0].weight, - v_t[0], v_t[1], v_t[2], v_t[3]); + "Deficit: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n", + rx_airtime, tx_airtime, sta->airtime_weight, + deficit[0], deficit[1], deficit[2], deficit[3]); rv = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); kfree(buf); @@ -236,11 +236,11 @@ static ssize_t sta_airtime_write(struct int ac; for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { - spin_lock_bh(&local->airtime[ac].lock); + spin_lock_bh(&local->active_txq_lock[ac]); sta->airtime[ac].rx_airtime = 0; sta->airtime[ac].tx_airtime = 0; - sta->airtime[ac].v_t = 0; - spin_unlock_bh(&local->airtime[ac].lock); + sta->airtime[ac].deficit = sta->airtime_weight; + spin_unlock_bh(&local->active_txq_lock[ac]); } return count; @@ -263,10 +263,10 @@ static ssize_t sta_aql_read(struct file return -ENOMEM; for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { - spin_lock_bh(&local->airtime[ac].lock); + spin_lock_bh(&local->active_txq_lock[ac]); q_limit_l[ac] = sta->airtime[ac].aql_limit_low; q_limit_h[ac] = sta->airtime[ac].aql_limit_high; - spin_unlock_bh(&local->airtime[ac].lock); + spin_unlock_bh(&local->active_txq_lock[ac]); q_depth[ac] = atomic_read(&sta->airtime[ac].aql_tx_pending); } --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -863,16 +863,20 @@ enum txq_info_flags { * @def_flow: used as a fallback flow when a packet destined to @tin hashes to * a fq_flow which is already owned by a different tin * @def_cvars: codel vars for @def_flow - * @schedule_order: used with ieee80211_local->active_txqs * @frags: used to keep fragments created after dequeue + * @schedule_order: used with ieee80211_local->active_txqs + * @schedule_round: counter to prevent infinite loops on TXQ scheduling */ struct txq_info { struct fq_tin tin; struct codel_vars def_cvars; struct codel_stats cstats; - struct rb_node schedule_order; + + u16 schedule_round; + struct list_head schedule_order; struct sk_buff_head frags; + unsigned long flags; /* keep last! */ @@ -949,8 +953,6 @@ struct ieee80211_sub_if_data { struct ieee80211_tx_queue_params tx_conf[IEEE80211_NUM_ACS]; struct mac80211_qos_map __rcu *qos_map; - struct airtime_info airtime[IEEE80211_NUM_ACS]; - struct work_struct csa_finalize_work; bool csa_block_tx; /* write-protected by sdata_lock and local->mtx */ struct cfg80211_chan_def csa_chandef; @@ -1185,44 +1187,6 @@ enum mac80211_scan_state { SCAN_ABORT, }; -/** - * struct airtime_sched_info - state used for airtime scheduling and AQL - * - * @lock: spinlock that protects all the fields in this struct - * @active_txqs: rbtree of currently backlogged queues, sorted by virtual time - * @schedule_pos: the current position maintained while a driver walks the tree - * with ieee80211_next_txq() - * @active_list: list of struct airtime_info structs that were active within - * the last AIRTIME_ACTIVE_DURATION (100 ms), used to compute - * weight_sum - * @last_weight_update: used for rate limiting walking active_list - * @last_schedule_time: tracks the last time a transmission was scheduled; used - * for catching up v_t if no stations are eligible for - * transmission. - * @v_t: global virtual time; queues with v_t < this are eligible for - * transmission - * @weight_sum: total sum of all active stations used for dividing airtime - * @weight_sum_reciprocal: reciprocal of weight_sum (to avoid divisions in fast - * path - see comment above - * IEEE80211_RECIPROCAL_DIVISOR_64) - * @aql_txq_limit_low: AQL limit when total outstanding airtime - * is < IEEE80211_AQL_THRESHOLD - * @aql_txq_limit_high: AQL limit when total outstanding airtime - * is > IEEE80211_AQL_THRESHOLD - */ -struct airtime_sched_info { - spinlock_t lock; - struct rb_root_cached active_txqs; - struct rb_node *schedule_pos; - struct list_head active_list; - u64 last_weight_update; - u64 last_schedule_activity; - u64 v_t; - u64 weight_sum; - u64 weight_sum_reciprocal; - u32 aql_txq_limit_low; - u32 aql_txq_limit_high; -}; DECLARE_STATIC_KEY_FALSE(aql_disable); struct ieee80211_local { @@ -1236,8 +1200,13 @@ struct ieee80211_local { struct codel_params cparams; /* protects active_txqs and txqi->schedule_order */ - struct airtime_sched_info airtime[IEEE80211_NUM_ACS]; + spinlock_t active_txq_lock[IEEE80211_NUM_ACS]; + struct list_head active_txqs[IEEE80211_NUM_ACS]; + u16 schedule_round[IEEE80211_NUM_ACS]; + u16 airtime_flags; + u32 aql_txq_limit_low[IEEE80211_NUM_ACS]; + u32 aql_txq_limit_high[IEEE80211_NUM_ACS]; u32 aql_threshold; atomic_t aql_total_pending_airtime; @@ -1654,125 +1623,6 @@ static inline bool txq_has_queue(struct return !(skb_queue_empty(&txqi->frags) && !txqi->tin.backlog_packets); } -static inline struct airtime_info *to_airtime_info(struct ieee80211_txq *txq) -{ - struct ieee80211_sub_if_data *sdata; - struct sta_info *sta; - - if (txq->sta) { - sta = container_of(txq->sta, struct sta_info, sta); - return &sta->airtime[txq->ac]; - } - - sdata = vif_to_sdata(txq->vif); - return &sdata->airtime[txq->ac]; -} - -/* To avoid divisions in the fast path, we keep pre-computed reciprocals for - * airtime weight calculations. There are two different weights to keep track - * of: The per-station weight and the sum of weights per phy. - * - * For the per-station weights (kept in airtime_info below), we use 32-bit - * reciprocals with a devisor of 2^19. This lets us keep the multiplications and - * divisions for the station weights as 32-bit operations at the cost of a bit - * of rounding error for high weights; but the choice of divisor keeps rounding - * errors <10% for weights <2^15, assuming no more than 8ms of airtime is - * reported at a time. - * - * For the per-phy sum of weights the values can get higher, so we use 64-bit - * operations for those with a 32-bit divisor, which should avoid any - * significant rounding errors. - */ -#define IEEE80211_RECIPROCAL_DIVISOR_64 0x100000000ULL -#define IEEE80211_RECIPROCAL_SHIFT_64 32 -#define IEEE80211_RECIPROCAL_DIVISOR_32 0x80000U -#define IEEE80211_RECIPROCAL_SHIFT_32 19 - -static inline void airtime_weight_set(struct airtime_info *air_info, u16 weight) -{ - if (air_info->weight == weight) - return; - - air_info->weight = weight; - if (weight) { - air_info->weight_reciprocal = - IEEE80211_RECIPROCAL_DIVISOR_32 / weight; - } else { - air_info->weight_reciprocal = 0; - } -} - -static inline void airtime_weight_sum_set(struct airtime_sched_info *air_sched, - int weight_sum) -{ - if (air_sched->weight_sum == weight_sum) - return; - - air_sched->weight_sum = weight_sum; - if (air_sched->weight_sum) { - air_sched->weight_sum_reciprocal = IEEE80211_RECIPROCAL_DIVISOR_64; - do_div(air_sched->weight_sum_reciprocal, air_sched->weight_sum); - } else { - air_sched->weight_sum_reciprocal = 0; - } -} - -/* A problem when trying to enforce airtime fairness is that we want to divide - * the airtime between the currently *active* stations. However, basing this on - * the instantaneous queue state of stations doesn't work, as queues tend to - * oscillate very quickly between empty and occupied, leading to the scheduler - * thinking only a single station is active when deciding whether to allow - * transmission (and thus not throttling correctly). - * - * To fix this we use a timer-based notion of activity: a station is considered - * active if it has been scheduled within the last 100 ms; we keep a separate - * list of all the stations considered active in this manner, and lazily update - * the total weight of active stations from this list (filtering the stations in - * the list by their 'last active' time). - * - * We add one additional safeguard to guard against stations that manage to get - * scheduled every 100 ms but don't transmit a lot of data, and thus don't use - * up any airtime. Such stations would be able to get priority for an extended - * period of time if they do start transmitting at full capacity again, and so - * we add an explicit maximum for how far behind a station is allowed to fall in - * the virtual airtime domain. This limit is set to a relatively high value of - * 20 ms because the main mechanism for catching up idle stations is the active - * state as described above; i.e., the hard limit should only be hit in - * pathological cases. - */ -#define AIRTIME_ACTIVE_DURATION (100 * NSEC_PER_MSEC) -#define AIRTIME_MAX_BEHIND 20000 /* 20 ms */ - -static inline bool airtime_is_active(struct airtime_info *air_info, u64 now) -{ - return air_info->last_scheduled >= now - AIRTIME_ACTIVE_DURATION; -} - -static inline void airtime_set_active(struct airtime_sched_info *air_sched, - struct airtime_info *air_info, u64 now) -{ - air_info->last_scheduled = now; - air_sched->last_schedule_activity = now; - list_move_tail(&air_info->list, &air_sched->active_list); -} - -static inline bool airtime_catchup_v_t(struct airtime_sched_info *air_sched, - u64 v_t, u64 now) -{ - air_sched->v_t = v_t; - return true; -} - -static inline void init_airtime_info(struct airtime_info *air_info, - struct airtime_sched_info *air_sched) -{ - atomic_set(&air_info->aql_tx_pending, 0); - air_info->aql_limit_low = air_sched->aql_txq_limit_low; - air_info->aql_limit_high = air_sched->aql_txq_limit_high; - airtime_weight_set(air_info, IEEE80211_DEFAULT_AIRTIME_WEIGHT); - INIT_LIST_HEAD(&air_info->list); -} - static inline int ieee80211_bssid_match(const u8 *raddr, const u8 *addr) { return ether_addr_equal(raddr, addr) || @@ -2018,14 +1868,6 @@ int ieee80211_tx_control_port(struct wip u64 *cookie); int ieee80211_probe_mesh_link(struct wiphy *wiphy, struct net_device *dev, const u8 *buf, size_t len); -void ieee80211_resort_txq(struct ieee80211_hw *hw, - struct ieee80211_txq *txq); -void ieee80211_unschedule_txq(struct ieee80211_hw *hw, - struct ieee80211_txq *txq, - bool purge); -void ieee80211_update_airtime_weight(struct ieee80211_local *local, - struct airtime_sched_info *air_sched, - u64 now, bool force); /* HT */ void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata, --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -2192,9 +2192,6 @@ int ieee80211_if_add(struct ieee80211_lo } } - for (i = 0; i < IEEE80211_NUM_ACS; i++) - init_airtime_info(&sdata->airtime[i], &local->airtime[i]); - ieee80211_set_default_queues(sdata); sdata->ap_power_level = IEEE80211_UNSET_POWER_LEVEL; --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -707,13 +707,10 @@ struct ieee80211_hw *ieee80211_alloc_hw_ spin_lock_init(&local->queue_stop_reason_lock); for (i = 0; i < IEEE80211_NUM_ACS; i++) { - struct airtime_sched_info *air_sched = &local->airtime[i]; - - air_sched->active_txqs = RB_ROOT_CACHED; - INIT_LIST_HEAD(&air_sched->active_list); - spin_lock_init(&air_sched->lock); - air_sched->aql_txq_limit_low = IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L; - air_sched->aql_txq_limit_high = + INIT_LIST_HEAD(&local->active_txqs[i]); + spin_lock_init(&local->active_txq_lock[i]); + local->aql_txq_limit_low[i] = IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L; + local->aql_txq_limit_high[i] = IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H; } --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1583,8 +1583,12 @@ static void sta_ps_start(struct sta_info for (tid = 0; tid < IEEE80211_NUM_TIDS; tid++) { struct ieee80211_txq *txq = sta->sta.txq[tid]; + struct txq_info *txqi = to_txq_info(txq); - ieee80211_unschedule_txq(&local->hw, txq, false); + spin_lock(&local->active_txq_lock[txq->ac]); + if (!list_empty(&txqi->schedule_order)) + list_del_init(&txqi->schedule_order); + spin_unlock(&local->active_txq_lock[txq->ac]); if (txq_has_queue(txq)) set_bit(tid, &sta->txq_buffered_tids); --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -426,11 +426,15 @@ struct sta_info *sta_info_alloc(struct i if (sta_prepare_rate_control(local, sta, gfp)) goto free_txq; + sta->airtime_weight = IEEE80211_DEFAULT_AIRTIME_WEIGHT; for (i = 0; i < IEEE80211_NUM_ACS; i++) { skb_queue_head_init(&sta->ps_tx_buf[i]); skb_queue_head_init(&sta->tx_filtered[i]); - init_airtime_info(&sta->airtime[i], &local->airtime[i]); + sta->airtime[i].deficit = sta->airtime_weight; + atomic_set(&sta->airtime[i].aql_tx_pending, 0); + sta->airtime[i].aql_limit_low = local->aql_txq_limit_low[i]; + sta->airtime[i].aql_limit_high = local->aql_txq_limit_high[i]; } for (i = 0; i < IEEE80211_NUM_TIDS; i++) @@ -1889,59 +1893,24 @@ void ieee80211_sta_set_buffered(struct i } EXPORT_SYMBOL(ieee80211_sta_set_buffered); -void ieee80211_register_airtime(struct ieee80211_txq *txq, - u32 tx_airtime, u32 rx_airtime) +void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid, + u32 tx_airtime, u32 rx_airtime) { - struct ieee80211_sub_if_data *sdata = vif_to_sdata(txq->vif); - struct ieee80211_local *local = sdata->local; - u64 weight_sum, weight_sum_reciprocal; - struct airtime_sched_info *air_sched; - struct airtime_info *air_info; + struct sta_info *sta = container_of(pubsta, struct sta_info, sta); + struct ieee80211_local *local = sta->sdata->local; + u8 ac = ieee80211_ac_from_tid(tid); u32 airtime = 0; - air_sched = &local->airtime[txq->ac]; - air_info = to_airtime_info(txq); - - if (local->airtime_flags & AIRTIME_USE_TX) + if (sta->local->airtime_flags & AIRTIME_USE_TX) airtime += tx_airtime; - if (local->airtime_flags & AIRTIME_USE_RX) + if (sta->local->airtime_flags & AIRTIME_USE_RX) airtime += rx_airtime; - /* Weights scale so the unit weight is 256 */ - airtime <<= 8; - - spin_lock_bh(&air_sched->lock); - - air_info->tx_airtime += tx_airtime; - air_info->rx_airtime += rx_airtime; - - if (air_sched->weight_sum) { - weight_sum = air_sched->weight_sum; - weight_sum_reciprocal = air_sched->weight_sum_reciprocal; - } else { - weight_sum = air_info->weight; - weight_sum_reciprocal = air_info->weight_reciprocal; - } - - /* Round the calculation of global vt */ - air_sched->v_t += (u64)((airtime + (weight_sum >> 1)) * - weight_sum_reciprocal) >> IEEE80211_RECIPROCAL_SHIFT_64; - air_info->v_t += (u32)((airtime + (air_info->weight >> 1)) * - air_info->weight_reciprocal) >> IEEE80211_RECIPROCAL_SHIFT_32; - ieee80211_resort_txq(&local->hw, txq); - - spin_unlock_bh(&air_sched->lock); -} - -void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid, - u32 tx_airtime, u32 rx_airtime) -{ - struct ieee80211_txq *txq = pubsta->txq[tid]; - - if (!txq) - return; - - ieee80211_register_airtime(txq, tx_airtime, rx_airtime); + spin_lock_bh(&local->active_txq_lock[ac]); + sta->airtime[ac].tx_airtime += tx_airtime; + sta->airtime[ac].rx_airtime += rx_airtime; + sta->airtime[ac].deficit -= airtime; + spin_unlock_bh(&local->active_txq_lock[ac]); } EXPORT_SYMBOL(ieee80211_sta_register_airtime); @@ -2385,7 +2354,7 @@ void sta_set_sinfo(struct sta_info *sta, } if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_AIRTIME_WEIGHT))) { - sinfo->airtime_weight = sta->airtime[0].weight; + sinfo->airtime_weight = sta->airtime_weight; sinfo->filled |= BIT_ULL(NL80211_STA_INFO_AIRTIME_WEIGHT); } --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -135,25 +135,18 @@ enum ieee80211_agg_stop_reason { #define AIRTIME_USE_TX BIT(0) #define AIRTIME_USE_RX BIT(1) - struct airtime_info { u64 rx_airtime; u64 tx_airtime; - u64 v_t; - u64 last_scheduled; - struct list_head list; + s64 deficit; atomic_t aql_tx_pending; /* Estimated airtime for frames pending */ u32 aql_limit_low; u32 aql_limit_high; - u32 weight_reciprocal; - u16 weight; }; void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local, struct sta_info *sta, u8 ac, u16 tx_airtime, bool tx_completed); -void ieee80211_register_airtime(struct ieee80211_txq *txq, - u32 tx_airtime, u32 rx_airtime); struct sta_info; @@ -523,6 +516,7 @@ struct ieee80211_fragment_cache { * @tid_seq: per-TID sequence numbers for sending to this STA * @airtime: per-AC struct airtime_info describing airtime statistics for this * station + * @airtime_weight: station weight for airtime fairness calculation purposes * @ampdu_mlme: A-MPDU state machine state * @mesh: mesh STA information * @debugfs_dir: debug filesystem directory dentry @@ -653,6 +647,7 @@ struct sta_info { u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1]; struct airtime_info airtime[IEEE80211_NUM_ACS]; + u16 airtime_weight; /* * Aggregation information, locked with lock. --- a/net/mac80211/status.c +++ b/net/mac80211/status.c @@ -983,25 +983,6 @@ static void __ieee80211_tx_status(struct if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked) ieee80211_frame_acked(sta, skb); - } else if (wiphy_ext_feature_isset(local->hw.wiphy, - NL80211_EXT_FEATURE_AIRTIME_FAIRNESS)) { - struct ieee80211_sub_if_data *sdata; - struct ieee80211_txq *txq; - u32 airtime; - - /* Account airtime to multicast queue */ - sdata = ieee80211_sdata_from_skb(local, skb); - - if (sdata && (txq = sdata->vif.txq)) { - airtime = info->status.tx_time ?: - ieee80211_calc_expected_tx_airtime(hw, - &sdata->vif, - NULL, - skb->len, - false); - - ieee80211_register_airtime(txq, airtime, 0); - } } /* SNMP counters --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -18,7 +18,6 @@ #include #include #include -#include #include #include #include @@ -1480,7 +1479,7 @@ void ieee80211_txq_init(struct ieee80211 codel_vars_init(&txqi->def_cvars); codel_stats_init(&txqi->cstats); __skb_queue_head_init(&txqi->frags); - RB_CLEAR_NODE(&txqi->schedule_order); + INIT_LIST_HEAD(&txqi->schedule_order); txqi->txq.vif = &sdata->vif; @@ -1524,7 +1523,9 @@ void ieee80211_txq_purge(struct ieee8021 ieee80211_purge_tx_queue(&local->hw, &txqi->frags); spin_unlock_bh(&fq->lock); - ieee80211_unschedule_txq(&local->hw, &txqi->txq, true); + spin_lock_bh(&local->active_txq_lock[txqi->txq.ac]); + list_del_init(&txqi->schedule_order); + spin_unlock_bh(&local->active_txq_lock[txqi->txq.ac]); } void ieee80211_txq_set_params(struct ieee80211_local *local) @@ -3819,259 +3820,102 @@ EXPORT_SYMBOL(ieee80211_tx_dequeue); struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac) { struct ieee80211_local *local = hw_to_local(hw); - struct airtime_sched_info *air_sched; - u64 now = ktime_get_coarse_boottime_ns(); struct ieee80211_txq *ret = NULL; - struct airtime_info *air_info; - struct txq_info *txqi = NULL; - struct rb_node *node; - bool first = false; + struct txq_info *txqi = NULL, *head = NULL; + bool found_eligible_txq = false; - air_sched = &local->airtime[ac]; - spin_lock_bh(&air_sched->lock); + spin_lock_bh(&local->active_txq_lock[ac]); - node = air_sched->schedule_pos; - -begin: - if (!node) { - node = rb_first_cached(&air_sched->active_txqs); - first = true; - } else { - node = rb_next(node); - } - - if (!node) - goto out; - - txqi = container_of(node, struct txq_info, schedule_order); - air_info = to_airtime_info(&txqi->txq); - - if (air_info->v_t > air_sched->v_t && - (!first || !airtime_catchup_v_t(air_sched, air_info->v_t, now))) + begin: + txqi = list_first_entry_or_null(&local->active_txqs[ac], + struct txq_info, + schedule_order); + if (!txqi) goto out; - if (!ieee80211_txq_airtime_check(hw, &txqi->txq)) { - first = false; - goto begin; - } - - air_sched->schedule_pos = node; - air_sched->last_schedule_activity = now; - ret = &txqi->txq; -out: - spin_unlock_bh(&air_sched->lock); - return ret; -} -EXPORT_SYMBOL(ieee80211_next_txq); - -static void __ieee80211_insert_txq(struct rb_root_cached *root, - struct txq_info *txqi) -{ - struct rb_node **new = &root->rb_root.rb_node; - struct airtime_info *old_air, *new_air; - struct rb_node *parent = NULL; - struct txq_info *__txqi; - bool leftmost = true; - - while (*new) { - parent = *new; - __txqi = rb_entry(parent, struct txq_info, schedule_order); - old_air = to_airtime_info(&__txqi->txq); - new_air = to_airtime_info(&txqi->txq); - - if (new_air->v_t <= old_air->v_t) { - new = &parent->rb_left; - } else { - new = &parent->rb_right; - leftmost = false; - } + if (txqi == head) { + if (!found_eligible_txq) + goto out; + else + found_eligible_txq = false; } - rb_link_node(&txqi->schedule_order, parent, new); - rb_insert_color_cached(&txqi->schedule_order, root, leftmost); -} - -void ieee80211_resort_txq(struct ieee80211_hw *hw, - struct ieee80211_txq *txq) -{ - struct airtime_info *air_info = to_airtime_info(txq); - struct ieee80211_local *local = hw_to_local(hw); - struct txq_info *txqi = to_txq_info(txq); - struct airtime_sched_info *air_sched; - - air_sched = &local->airtime[txq->ac]; + if (!head) + head = txqi; - lockdep_assert_held(&air_sched->lock); - - if (!RB_EMPTY_NODE(&txqi->schedule_order)) { - struct airtime_info *a_prev = NULL, *a_next = NULL; - struct txq_info *t_prev, *t_next; - struct rb_node *n_prev, *n_next; + if (txqi->txq.sta) { + struct sta_info *sta = container_of(txqi->txq.sta, + struct sta_info, sta); + bool aql_check = ieee80211_txq_airtime_check(hw, &txqi->txq); + s64 deficit = sta->airtime[txqi->txq.ac].deficit; - /* Erasing a node can cause an expensive rebalancing operation, - * so we check the previous and next nodes first and only remove - * and re-insert if the current node is not already in the - * correct position. - */ - if ((n_prev = rb_prev(&txqi->schedule_order)) != NULL) { - t_prev = container_of(n_prev, struct txq_info, - schedule_order); - a_prev = to_airtime_info(&t_prev->txq); - } + if (aql_check) + found_eligible_txq = true; - if ((n_next = rb_next(&txqi->schedule_order)) != NULL) { - t_next = container_of(n_next, struct txq_info, - schedule_order); - a_next = to_airtime_info(&t_next->txq); + if (deficit < 0) + sta->airtime[txqi->txq.ac].deficit += + sta->airtime_weight; + + if (deficit < 0 || !aql_check) { + list_move_tail(&txqi->schedule_order, + &local->active_txqs[txqi->txq.ac]); + goto begin; } - - if ((!a_prev || a_prev->v_t <= air_info->v_t) && - (!a_next || a_next->v_t > air_info->v_t)) - return; - - if (air_sched->schedule_pos == &txqi->schedule_order) - air_sched->schedule_pos = n_prev; - - rb_erase_cached(&txqi->schedule_order, - &air_sched->active_txqs); - RB_CLEAR_NODE(&txqi->schedule_order); - __ieee80211_insert_txq(&air_sched->active_txqs, txqi); } -} - -void ieee80211_update_airtime_weight(struct ieee80211_local *local, - struct airtime_sched_info *air_sched, - u64 now, bool force) -{ - struct airtime_info *air_info, *tmp; - u64 weight_sum = 0; - - if (unlikely(!now)) - now = ktime_get_coarse_boottime_ns(); - - lockdep_assert_held(&air_sched->lock); - - if (!force && (air_sched->last_weight_update < - now - AIRTIME_ACTIVE_DURATION)) - return; - - list_for_each_entry_safe(air_info, tmp, - &air_sched->active_list, list) { - if (airtime_is_active(air_info, now)) - weight_sum += air_info->weight; - else - list_del_init(&air_info->list); - } - airtime_weight_sum_set(air_sched, weight_sum); - air_sched->last_weight_update = now; -} -void ieee80211_schedule_txq(struct ieee80211_hw *hw, - struct ieee80211_txq *txq) - __acquires(txq_lock) __releases(txq_lock) -{ - struct ieee80211_local *local = hw_to_local(hw); - struct txq_info *txqi = to_txq_info(txq); - struct airtime_sched_info *air_sched; - u64 now = ktime_get_coarse_boottime_ns(); - struct airtime_info *air_info; - u8 ac = txq->ac; - bool was_active; - air_sched = &local->airtime[ac]; - air_info = to_airtime_info(txq); - - spin_lock_bh(&air_sched->lock); - was_active = airtime_is_active(air_info, now); - airtime_set_active(air_sched, air_info, now); - - if (!RB_EMPTY_NODE(&txqi->schedule_order)) + if (txqi->schedule_round == local->schedule_round[ac]) goto out; - /* If the station has been inactive for a while, catch up its v_t so it - * doesn't get indefinite priority; see comment above the definition of - * AIRTIME_MAX_BEHIND. - */ - if ((!was_active && air_info->v_t < air_sched->v_t) || - air_info->v_t < air_sched->v_t - AIRTIME_MAX_BEHIND) - air_info->v_t = air_sched->v_t; - - ieee80211_update_airtime_weight(local, air_sched, now, !was_active); - __ieee80211_insert_txq(&air_sched->active_txqs, txqi); + list_del_init(&txqi->schedule_order); + txqi->schedule_round = local->schedule_round[ac]; + ret = &txqi->txq; out: - spin_unlock_bh(&air_sched->lock); -} -EXPORT_SYMBOL(ieee80211_schedule_txq); - -static void __ieee80211_unschedule_txq(struct ieee80211_hw *hw, - struct ieee80211_txq *txq, - bool purge) -{ - struct ieee80211_local *local = hw_to_local(hw); - struct txq_info *txqi = to_txq_info(txq); - struct airtime_sched_info *air_sched; - struct airtime_info *air_info; - - air_sched = &local->airtime[txq->ac]; - air_info = to_airtime_info(&txqi->txq); - - lockdep_assert_held(&air_sched->lock); - - if (purge) { - list_del_init(&air_info->list); - ieee80211_update_airtime_weight(local, air_sched, 0, true); - } - - if (RB_EMPTY_NODE(&txqi->schedule_order)) - return; - - if (air_sched->schedule_pos == &txqi->schedule_order) - air_sched->schedule_pos = rb_prev(&txqi->schedule_order); - - if (!purge) - airtime_set_active(air_sched, air_info, - ktime_get_coarse_boottime_ns()); - - rb_erase_cached(&txqi->schedule_order, - &air_sched->active_txqs); - RB_CLEAR_NODE(&txqi->schedule_order); + spin_unlock_bh(&local->active_txq_lock[ac]); + return ret; } +EXPORT_SYMBOL(ieee80211_next_txq); -void ieee80211_unschedule_txq(struct ieee80211_hw *hw, +void __ieee80211_schedule_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq, - bool purge) - __acquires(txq_lock) __releases(txq_lock) -{ - struct ieee80211_local *local = hw_to_local(hw); - - spin_lock_bh(&local->airtime[txq->ac].lock); - __ieee80211_unschedule_txq(hw, txq, purge); - spin_unlock_bh(&local->airtime[txq->ac].lock); -} - -void ieee80211_return_txq(struct ieee80211_hw *hw, - struct ieee80211_txq *txq, bool force) + bool force) { struct ieee80211_local *local = hw_to_local(hw); struct txq_info *txqi = to_txq_info(txq); - spin_lock_bh(&local->airtime[txq->ac].lock); + spin_lock_bh(&local->active_txq_lock[txq->ac]); - if (!RB_EMPTY_NODE(&txqi->schedule_order) && !force && - !txq_has_queue(txq)) - __ieee80211_unschedule_txq(hw, txq, false); + if (list_empty(&txqi->schedule_order) && + (force || !skb_queue_empty(&txqi->frags) || + txqi->tin.backlog_packets)) { + /* If airtime accounting is active, always enqueue STAs at the + * head of the list to ensure that they only get moved to the + * back by the airtime DRR scheduler once they have a negative + * deficit. A station that already has a negative deficit will + * get immediately moved to the back of the list on the next + * call to ieee80211_next_txq(). + */ + if (txqi->txq.sta && local->airtime_flags && + wiphy_ext_feature_isset(local->hw.wiphy, + NL80211_EXT_FEATURE_AIRTIME_FAIRNESS)) + list_add(&txqi->schedule_order, + &local->active_txqs[txq->ac]); + else + list_add_tail(&txqi->schedule_order, + &local->active_txqs[txq->ac]); + } - spin_unlock_bh(&local->airtime[txq->ac].lock); + spin_unlock_bh(&local->active_txq_lock[txq->ac]); } -EXPORT_SYMBOL(ieee80211_return_txq); +EXPORT_SYMBOL(__ieee80211_schedule_txq); DEFINE_STATIC_KEY_FALSE(aql_disable); bool ieee80211_txq_airtime_check(struct ieee80211_hw *hw, struct ieee80211_txq *txq) { - struct airtime_info *air_info = to_airtime_info(txq); + struct sta_info *sta; struct ieee80211_local *local = hw_to_local(hw); if (!wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) @@ -4086,12 +3930,15 @@ bool ieee80211_txq_airtime_check(struct if (unlikely(txq->tid == IEEE80211_NUM_TIDS)) return true; - if (atomic_read(&air_info->aql_tx_pending) < air_info->aql_limit_low) + sta = container_of(txq->sta, struct sta_info, sta); + if (atomic_read(&sta->airtime[txq->ac].aql_tx_pending) < + sta->airtime[txq->ac].aql_limit_low) return true; if (atomic_read(&local->aql_total_pending_airtime) < local->aql_threshold && - atomic_read(&air_info->aql_tx_pending) < air_info->aql_limit_high) + atomic_read(&sta->airtime[txq->ac].aql_tx_pending) < + sta->airtime[txq->ac].aql_limit_high) return true; return false; @@ -4101,59 +3948,60 @@ EXPORT_SYMBOL(ieee80211_txq_airtime_chec bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw, struct ieee80211_txq *txq) { - struct txq_info *first_txqi = NULL, *txqi = to_txq_info(txq); struct ieee80211_local *local = hw_to_local(hw); - struct airtime_sched_info *air_sched; - struct airtime_info *air_info; - struct rb_node *node = NULL; - bool ret = false; - u64 now; - + struct txq_info *iter, *tmp, *txqi = to_txq_info(txq); + struct sta_info *sta; + u8 ac = txq->ac; - if (!ieee80211_txq_airtime_check(hw, txq)) - return false; + spin_lock_bh(&local->active_txq_lock[ac]); - air_sched = &local->airtime[txq->ac]; - spin_lock_bh(&air_sched->lock); + if (!txqi->txq.sta) + goto out; - if (RB_EMPTY_NODE(&txqi->schedule_order)) + if (list_empty(&txqi->schedule_order)) goto out; - now = ktime_get_coarse_boottime_ns(); + list_for_each_entry_safe(iter, tmp, &local->active_txqs[ac], + schedule_order) { + if (iter == txqi) + break; - /* Like in ieee80211_next_txq(), make sure the first station in the - * scheduling order is eligible for transmission to avoid starvation. - */ - node = rb_first_cached(&air_sched->active_txqs); - if (node) { - first_txqi = container_of(node, struct txq_info, - schedule_order); - air_info = to_airtime_info(&first_txqi->txq); - - if (air_sched->v_t < air_info->v_t) - airtime_catchup_v_t(air_sched, air_info->v_t, now); + if (!iter->txq.sta) { + list_move_tail(&iter->schedule_order, + &local->active_txqs[ac]); + continue; + } + sta = container_of(iter->txq.sta, struct sta_info, sta); + if (sta->airtime[ac].deficit < 0) + sta->airtime[ac].deficit += sta->airtime_weight; + list_move_tail(&iter->schedule_order, &local->active_txqs[ac]); } - air_info = to_airtime_info(&txqi->txq); - if (air_info->v_t <= air_sched->v_t) { - air_sched->last_schedule_activity = now; - ret = true; - } + sta = container_of(txqi->txq.sta, struct sta_info, sta); + if (sta->airtime[ac].deficit >= 0) + goto out; + + sta->airtime[ac].deficit += sta->airtime_weight; + list_move_tail(&txqi->schedule_order, &local->active_txqs[ac]); + spin_unlock_bh(&local->active_txq_lock[ac]); + return false; out: - spin_unlock_bh(&air_sched->lock); - return ret; + if (!list_empty(&txqi->schedule_order)) + list_del_init(&txqi->schedule_order); + spin_unlock_bh(&local->active_txq_lock[ac]); + + return true; } EXPORT_SYMBOL(ieee80211_txq_may_transmit); void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac) { struct ieee80211_local *local = hw_to_local(hw); - struct airtime_sched_info *air_sched = &local->airtime[ac]; - spin_lock_bh(&air_sched->lock); - air_sched->schedule_pos = NULL; - spin_unlock_bh(&air_sched->lock); + spin_lock_bh(&local->active_txq_lock[ac]); + local->schedule_round[ac]++; + spin_unlock_bh(&local->active_txq_lock[ac]); } EXPORT_SYMBOL(ieee80211_txq_schedule_start);