mac80211: add AQL support for broadcast/multicast packets

Should improve performance/reliability with lots of mcast packets

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/kernel/mac80211/patches/subsys/330-mac80211-add-AQL-support-for-broadcast-packets.patch

@@ -0,0 +1,226 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Fri, 9 Feb 2024 19:43:40 +0100
+Subject: [PATCH] mac80211: add AQL support for broadcast packets
+
+Excessive broadcast traffic with little competing unicast traffic can easily
+flood hardware queues, leading to throughput issues. Additionally, filling
+the hardware queues with too many packets breaks FQ for broadcast data.
+Fix this by enabling AQL for broadcast packets.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/cfg80211.h
++++ b/include/net/cfg80211.h
+@@ -3324,6 +3324,7 @@ enum wiphy_params_flags {
+ /* The per TXQ device queue limit in airtime */
+ #define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L	5000
+ #define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H	12000
++#define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_BC	50000
+
+ /* The per interface airtime threshold to switch to lower queue limit */
+ #define IEEE80211_AQL_THRESHOLD			24000
+--- a/net/mac80211/debugfs.c
++++ b/net/mac80211/debugfs.c
+@@ -215,11 +215,13 @@ static ssize_t aql_pending_read(struct f
+ 			"VI     %u us\n"
+ 			"BE     %u us\n"
+ 			"BK     %u us\n"
++			"BC/MC  %u us\n"
+ 			"total  %u us\n",
+ 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_VO]),
+ 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_VI]),
+ 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_BE]),
+ 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_BK]),
++			atomic_read(&local->aql_bc_pending_airtime),
+ 			atomic_read(&local->aql_total_pending_airtime));
+ 	return simple_read_from_buffer(user_buf, count, ppos,
+ 				       buf, len);
+@@ -245,7 +247,8 @@ static ssize_t aql_txq_limit_read(struct
+ 			"VO	%u		%u\n"
+ 			"VI	%u		%u\n"
+ 			"BE	%u		%u\n"
+-			"BK	%u		%u\n",
++			"BK	%u		%u\n"
++			"BC/MC	%u\n",
+ 			local->aql_txq_limit_low[IEEE80211_AC_VO],
+ 			local->aql_txq_limit_high[IEEE80211_AC_VO],
+ 			local->aql_txq_limit_low[IEEE80211_AC_VI],
+@@ -253,7 +256,8 @@ static ssize_t aql_txq_limit_read(struct
+ 			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]);
++			local->aql_txq_limit_high[IEEE80211_AC_BK],
++			local->aql_txq_limit_bc);
+ 	return simple_read_from_buffer(user_buf, count, ppos,
+ 				       buf, len);
+ }
+@@ -279,6 +283,11 @@ static ssize_t aql_txq_limit_write(struc
+ 	else
+ 		buf[count] = '\0';
+
++	if (sscanf(buf, "mcast %u", &q_limit_low) == 1) {
++		local->aql_txq_limit_bc = q_limit_low;
++		return count;
++	}
++
+ 	if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3)
+ 		return -EINVAL;
+
+--- a/net/mac80211/ieee80211_i.h
++++ b/net/mac80211/ieee80211_i.h
+@@ -1328,10 +1328,12 @@ struct ieee80211_local {
+ 	spinlock_t handle_wake_tx_queue_lock;
+
+ 	u16 airtime_flags;
++	u32 aql_txq_limit_bc;
+ 	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;
++	atomic_t aql_bc_pending_airtime;
+ 	atomic_t aql_ac_pending_airtime[IEEE80211_NUM_ACS];
+
+ 	const struct ieee80211_ops *ops;
+--- a/net/mac80211/main.c
++++ b/net/mac80211/main.c
+@@ -788,6 +788,7 @@ struct ieee80211_hw *ieee80211_alloc_hw_
+ 	spin_lock_init(&local->rx_path_lock);
+ 	spin_lock_init(&local->queue_stop_reason_lock);
+
++	local->aql_txq_limit_bc = IEEE80211_DEFAULT_AQL_TXQ_LIMIT_BC;
+ 	for (i = 0; i < IEEE80211_NUM_ACS; i++) {
+ 		INIT_LIST_HEAD(&local->active_txqs[i]);
+ 		spin_lock_init(&local->active_txq_lock[i]);
+--- a/net/mac80211/sta_info.c
++++ b/net/mac80211/sta_info.c
+@@ -2341,28 +2341,27 @@ void ieee80211_sta_update_pending_airtim
+ 					  struct sta_info *sta, u8 ac,
+ 					  u16 tx_airtime, bool tx_completed)
+ {
++	atomic_t *counter;
+ 	int tx_pending;
+
+ 	if (!wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))
+ 		return;
+
+-	if (!tx_completed) {
+-		if (sta)
+-			atomic_add(tx_airtime,
+-				   &sta->airtime[ac].aql_tx_pending);
++	if (sta)
++		counter = &sta->airtime[ac].aql_tx_pending;
++	else
++		counter = &local->aql_bc_pending_airtime;
+
++	if (!tx_completed) {
++		atomic_add(tx_airtime, counter);
+ 		atomic_add(tx_airtime, &local->aql_total_pending_airtime);
+ 		atomic_add(tx_airtime, &local->aql_ac_pending_airtime[ac]);
+ 		return;
+ 	}
+
+-	if (sta) {
+-		tx_pending = atomic_sub_return(tx_airtime,
+-					       &sta->airtime[ac].aql_tx_pending);
+-		if (tx_pending < 0)
+-			atomic_cmpxchg(&sta->airtime[ac].aql_tx_pending,
+-				       tx_pending, 0);
+-	}
++	tx_pending = atomic_sub_return(tx_airtime, counter);
++	if (tx_pending < 0)
++		atomic_cmpxchg(counter, tx_pending, 0);
+
+ 	atomic_sub(tx_airtime, &local->aql_total_pending_airtime);
+ 	tx_pending = atomic_sub_return(tx_airtime,
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -3958,9 +3958,8 @@ begin:
+ encap_out:
+ 	IEEE80211_SKB_CB(skb)->control.vif = vif;
+
+-	if (tx.sta &&
+-	    wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
+-		bool ampdu = txq->ac != IEEE80211_AC_VO;
++	if (wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
++		bool ampdu = txq->sta && txq->ac != IEEE80211_AC_VO;
+ 		u32 airtime;
+
+ 		airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
+@@ -4026,6 +4025,7 @@ struct ieee80211_txq *ieee80211_next_txq
+ 	struct ieee80211_txq *ret = NULL;
+ 	struct txq_info *txqi = NULL, *head = NULL;
+ 	bool found_eligible_txq = false;
++	bool aql_check;
+
+ 	spin_lock_bh(&local->active_txq_lock[ac]);
+
+@@ -4049,26 +4049,26 @@ struct ieee80211_txq *ieee80211_next_txq
+ 	if (!head)
+ 		head = txqi;
+
++	aql_check = ieee80211_txq_airtime_check(hw, &txqi->txq);
++	if (aql_check)
++		found_eligible_txq = true;
++
+ 	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);
+-		s32 deficit = ieee80211_sta_deficit(sta, txqi->txq.ac);
+-
+-		if (aql_check)
+-			found_eligible_txq = true;
+-
+-		if (deficit < 0)
++		if (ieee80211_sta_deficit(sta, txqi->txq.ac) < 0) {
+ 			sta->airtime[txqi->txq.ac].deficit +=
+ 				sta->airtime_weight << AIRTIME_QUANTUM_SHIFT;
+-
+-		if (deficit < 0 || !aql_check) {
+-			list_move_tail(&txqi->schedule_order,
+-				       &local->active_txqs[txqi->txq.ac]);
+-			goto begin;
++			aql_check = false;
+ 		}
+ 	}
+
++	if (!aql_check) {
++		list_move_tail(&txqi->schedule_order,
++				   &local->active_txqs[txqi->txq.ac]);
++		goto begin;
++	}
++
+ 	if (txqi->schedule_round == local->schedule_round[ac])
+ 		goto out;
+
+@@ -4133,7 +4133,8 @@ bool ieee80211_txq_airtime_check(struct
+ 		return true;
+
+ 	if (!txq->sta)
+-		return true;
++		return atomic_read(&local->aql_bc_pending_airtime) <
++		       local->aql_txq_limit_bc;
+
+ 	if (unlikely(txq->tid == IEEE80211_NUM_TIDS))
+ 		return true;
+@@ -4182,15 +4183,15 @@ bool ieee80211_txq_may_transmit(struct i
+
+ 	spin_lock_bh(&local->active_txq_lock[ac]);
+
+-	if (!txqi->txq.sta)
+-		goto out;
+-
+ 	if (list_empty(&txqi->schedule_order))
+ 		goto out;
+
+ 	if (!ieee80211_txq_schedule_airtime_check(local, ac))
+ 		goto out;
+
++	if (!txqi->txq.sta)
++		goto out;
++
+ 	list_for_each_entry_safe(iter, tmp, &local->active_txqs[ac],
+ 				 schedule_order) {
+ 		if (iter == txqi)