mt76: reduce q->lock hold time

Instead of holding it for the duration of an entire station schedule run,
which can block out competing tasks for a significant amount of time,
only hold it for scheduling one batch of packets for one station.
Improves responsiveness under load

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

diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c
index 92e1c09..b8fe8ad 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/tx.c
+++ b/drivers/net/wireless/mediatek/mt76/tx.c
@@ -460,7 +460,6 @@ mt76_txq_schedule_list(struct mt76_phy *phy, enum mt76_txq_id qid)
        struct mt76_wcid *wcid;
        int ret = 0;
 
-       spin_lock_bh(&q->lock);
        while (1) {
                if (test_bit(MT76_STATE_PM, &phy->state) ||
                    test_bit(MT76_RESET, &phy->state)) {
@@ -470,14 +469,9 @@ mt76_txq_schedule_list(struct mt76_phy *phy, enum mt76_txq_id qid)
 
                if (dev->queue_ops->tx_cleanup &&
                    q->queued + 2 * MT_TXQ_FREE_THR >= q->ndesc) {
-                       spin_unlock_bh(&q->lock);
                        dev->queue_ops->tx_cleanup(dev, q, false);
-                       spin_lock_bh(&q->lock);
                }
 
-               if (mt76_txq_stopped(q))
-                       break;
-
                txq = ieee80211_next_txq(phy->hw, qid);
                if (!txq)
                        break;
@@ -487,6 +481,8 @@ mt76_txq_schedule_list(struct mt76_phy *phy, enum mt76_txq_id qid)
                if (wcid && test_bit(MT_WCID_FLAG_PS, &wcid->flags))
                        continue;
 
+               spin_lock_bh(&q->lock);
+
                if (mtxq->send_bar && mtxq->aggr) {
                        struct ieee80211_txq *txq = mtxq_to_txq(mtxq);
                        struct ieee80211_sta *sta = txq->sta;
@@ -500,10 +496,13 @@ mt76_txq_schedule_list(struct mt76_phy *phy, enum mt76_txq_id qid)
                        spin_lock_bh(&q->lock);
                }
 
-               ret += mt76_txq_send_burst(phy, q, mtxq);
+               if (!mt76_txq_stopped(q))
+                       ret += mt76_txq_send_burst(phy, q, mtxq);
+
+               spin_unlock_bh(&q->lock);
+
                ieee80211_return_txq(phy->hw, txq, false);
        }
-       spin_unlock_bh(&q->lock);
 
        return ret;
 }