[PATCH 5.11 468/601] mt76: reduce q->lock hold time

Greg Kroah-Hartman
2021-05-12T17:55:45Z

From: Felix Fietkau <nbd@nbd.name>

[ Upstream commit 2fbcdb4386dda0a911b5485b33468540716251f8 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/mediatek/mt76/tx.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c
index 25627e70bdad..d5953223d7cf 100644
--- a/drivers/net/wireless/mediatek/mt76/tx.c
+++ b/drivers/net/wireless/mediatek/mt76/tx.c
@@ -454,7 +454,6 @@ 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)) {
@@ -464,14 +463,9 @@ 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;
@@ -481,6 +475,8 @@ 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;
@@ -494,10 +490,13 @@ 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;
}
--
2.30.2