2020-12-04 13:19:58

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 1/3] mt76: improve tx queue stop/wake

Instead of stopping and waking only a single queue, handle all phy tx queues
mapped ot the same hardware queue.
Also allow the driver to block tx queues

Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/mediatek/mt76/dma.c | 10 ----------
drivers/net/wireless/mediatek/mt76/mt76.h | 1 +
drivers/net/wireless/mediatek/mt76/tx.c | 23 ++++++++++++-----------
3 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index bab961ebdf1c..6255f4f0a455 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -220,7 +220,6 @@ static void
mt76_dma_tx_cleanup(struct mt76_dev *dev, struct mt76_queue *q, bool flush)
{
struct mt76_queue_entry entry;
- bool wake = false;
int last;

if (!q)
@@ -238,7 +237,6 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, struct mt76_queue *q, bool flush)
if (entry.txwi) {
if (!(dev->drv->drv_flags & MT_DRV_TXWI_NO_FREE))
mt76_put_txwi(dev, entry.txwi);
- wake = !flush;
}

if (!flush && q->tail == last)
@@ -253,16 +251,8 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, struct mt76_queue *q, bool flush)
spin_unlock_bh(&q->lock);
}

- wake = wake && q->stopped &&
- q->qid < IEEE80211_NUM_ACS && q->queued < q->ndesc - 8;
- if (wake)
- q->stopped = false;
-
if (!q->queued)
wake_up(&dev->tx_wait);
-
- if (wake)
- ieee80211_wake_queue(dev->hw, q->qid);
}

static void *
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 15d52af24d12..ea80ae188dd6 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -136,6 +136,7 @@ struct mt76_queue {
int queued;
int buf_size;
bool stopped;
+ bool blocked;

u8 buf_offset;
u8 hw_idx;
diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c
index 65360067b8fa..4026e5f4f3f3 100644
--- a/drivers/net/wireless/mediatek/mt76/tx.c
+++ b/drivers/net/wireless/mediatek/mt76/tx.c
@@ -291,12 +291,6 @@ mt76_tx(struct mt76_phy *phy, struct ieee80211_sta *sta,
spin_lock_bh(&q->lock);
__mt76_tx_queue_skb(phy, qid, skb, wcid, sta, NULL);
dev->queue_ops->kick(dev, q);
-
- if (q->queued > q->ndesc - 8 && !q->stopped) {
- ieee80211_stop_queue(phy->hw, skb_get_queue_mapping(skb));
- q->stopped = true;
- }
-
spin_unlock_bh(&q->lock);
}
EXPORT_SYMBOL_GPL(mt76_tx);
@@ -381,6 +375,13 @@ mt76_release_buffered_frames(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
}
EXPORT_SYMBOL_GPL(mt76_release_buffered_frames);

+static bool
+mt76_txq_stopped(struct mt76_queue *q)
+{
+ return q->stopped || q->blocked ||
+ q->queued + MT_TXQ_FREE_THR >= q->ndesc;
+}
+
static int
mt76_txq_send_burst(struct mt76_phy *phy, struct mt76_queue *q,
struct mt76_txq *mtxq)
@@ -419,10 +420,7 @@ mt76_txq_send_burst(struct mt76_phy *phy, struct mt76_queue *q,
test_bit(MT76_RESET, &phy->state))
return -EBUSY;

- if (stop)
- break;
-
- if (q->queued + MT_TXQ_FREE_THR >= q->ndesc)
+ if (stop || mt76_txq_stopped(q))
break;

skb = mt76_txq_dequeue(phy, mtxq);
@@ -463,7 +461,7 @@ mt76_txq_schedule_list(struct mt76_phy *phy, enum mt76_txq_id qid)
break;
}

- if (q->queued + MT_TXQ_FREE_THR >= q->ndesc)
+ if (mt76_txq_stopped(q))
break;

txq = ieee80211_next_txq(phy->hw, qid);
@@ -498,11 +496,14 @@ mt76_txq_schedule_list(struct mt76_phy *phy, enum mt76_txq_id qid)

void mt76_txq_schedule(struct mt76_phy *phy, enum mt76_txq_id qid)
{
+ struct mt76_queue *q;
int len;

if (qid >= 4)
return;

+ q = phy->q_tx[qid];
+
rcu_read_lock();

do {
--
2.28.0


2020-12-04 13:23:06

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 2/3] mt76: mt7915: stop queues when running out of tx tokens

Avoids packet drops under load with lots of stations

Signed-off-by: Felix Fietkau <[email protected]>
---
.../net/wireless/mediatek/mt76/mt7915/init.c | 1 +
.../net/wireless/mediatek/mt76/mt7915/mac.c | 39 +++++++++++++++++++
.../wireless/mediatek/mt76/mt7915/mt7915.h | 2 +
3 files changed, 42 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
index ff29a8090739..ed4635bd151a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
@@ -690,6 +690,7 @@ void mt7915_unregister_device(struct mt7915_dev *dev)
ieee80211_free_txskb(hw, txwi->skb);
}
mt76_put_txwi(&dev->mt76, txwi);
+ dev->token_count--;
}
spin_unlock_bh(&dev->token_lock);
idr_destroy(&dev->token);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index a7fa6fffffff..71714b22188a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -918,6 +918,26 @@ void mt7915_mac_write_txwi(struct mt7915_dev *dev, __le32 *txwi,
mt7915_mac_write_txwi_tm(dev, mphy, txwi, skb);
}

+static void
+mt7915_set_tx_blocked(struct mt7915_dev *dev, bool blocked)
+{
+ struct mt76_phy *mphy = &dev->mphy, *mphy2 = dev->mt76.phy2;
+ struct mt76_queue *q, *q2 = NULL;
+
+ q = mphy->q_tx[0];
+ if (blocked == q->blocked)
+ return;
+
+ q->blocked = blocked;
+ if (mphy2) {
+ q2 = mphy2->q_tx[0];
+ q2->blocked = blocked;
+ }
+
+ if (!blocked)
+ mt76_worker_schedule(&dev->mt76.tx_worker);
+}
+
int mt7915_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
enum mt76_txq_id qid, struct mt76_wcid *wcid,
struct ieee80211_sta *sta,
@@ -974,7 +994,13 @@ int mt7915_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,

spin_lock_bh(&dev->token_lock);
id = idr_alloc(&dev->token, t, 0, MT7915_TOKEN_SIZE, GFP_ATOMIC);
+ if (id >= 0)
+ dev->token_count++;
+
+ if (dev->token_count >= MT7915_TOKEN_SIZE - MT7915_TOKEN_FREE_THR)
+ mt7915_set_tx_blocked(dev, true);
spin_unlock_bh(&dev->token_lock);
+
if (id < 0)
return id;

@@ -1083,6 +1109,7 @@ void mt7915_mac_tx_free(struct mt7915_dev *dev, struct sk_buff *skb)
LIST_HEAD(free_list);
struct sk_buff *tmp;
u8 i, count;
+ bool wake = false;

/* clean DMA queues and unmap buffers first */
mt76_queue_tx_cleanup(dev, dev->mphy.q_tx[MT_TXQ_PSD], false);
@@ -1135,6 +1162,11 @@ void mt7915_mac_tx_free(struct mt7915_dev *dev, struct sk_buff *skb)

spin_lock_bh(&dev->token_lock);
txwi = idr_remove(&dev->token, msdu);
+ if (txwi)
+ dev->token_count--;
+ if (dev->token_count < MT7915_TOKEN_SIZE - MT7915_TOKEN_FREE_THR &&
+ dev->mphy.q_tx[0]->blocked)
+ wake = true;
spin_unlock_bh(&dev->token_lock);

if (!txwi)
@@ -1165,6 +1197,13 @@ void mt7915_mac_tx_free(struct mt7915_dev *dev, struct sk_buff *skb)
}

mt7915_mac_sta_poll(dev);
+
+ if (wake) {
+ spin_lock_bh(&dev->token_lock);
+ mt7915_set_tx_blocked(dev, false);
+ spin_unlock_bh(&dev->token_lock);
+ }
+
mt76_worker_schedule(&dev->mt76.tx_worker);

napi_consume_skb(skb, 1);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h b/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
index 30e53a0f01fb..0339abf360d3 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h
@@ -32,6 +32,7 @@

#define MT7915_EEPROM_SIZE 3584
#define MT7915_TOKEN_SIZE 8192
+#define MT7915_TOKEN_FREE_THR 64

#define MT7915_CFEND_RATE_DEFAULT 0x49 /* OFDM 24M */
#define MT7915_CFEND_RATE_11B 0x03 /* 11B LP, 11M */
@@ -161,6 +162,7 @@ struct mt7915_dev {
u32 hw_pattern;

spinlock_t token_lock;
+ int token_count;
struct idr token;

s8 **rate_power; /* TODO: use mt76_rate_power */
--
2.28.0