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wl12xx: Change TX queue to be per AC
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With the current single-queue implementation traffic priorization is not
working correctly - when using multiple BE streams and one, say VI stream,
the VI stream will share bandwidth almost equally with the BE streams.

To fix the issue, implement per AC queues, which are emptied in priority
order to the firmware. To keep it relatively simple, maintain a global
buffer count and global queue stop/wake instead of per-AC.

With these changes, priorization appears to work just fine.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
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Juuso Oikarinen authored and Luciano Coelho committed Dec 15, 2010
1 parent 17c1755 commit 6742f55
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Showing 4 changed files with 60 additions and 17 deletions.
2 changes: 1 addition & 1 deletion drivers/net/wireless/wl12xx/debugfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -225,7 +225,7 @@ static ssize_t tx_queue_len_read(struct file *file, char __user *userbuf,
char buf[20];
int res;

queue_len = skb_queue_len(&wl->tx_queue);
queue_len = wl->tx_queue_count;

res = scnprintf(buf, sizeof(buf), "%u\n", queue_len);
return simple_read_from_buffer(userbuf, count, ppos, buf, res);
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12 changes: 8 additions & 4 deletions drivers/net/wireless/wl12xx/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -570,7 +570,7 @@ static void wl1271_irq_work(struct work_struct *work)

/* Check if any tx blocks were freed */
if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
!skb_queue_empty(&wl->tx_queue)) {
wl->tx_queue_count) {
/*
* In order to avoid starvation of the TX path,
* call the work function directly.
Expand Down Expand Up @@ -891,6 +891,7 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
struct ieee80211_sta *sta = txinfo->control.sta;
unsigned long flags;
int q;

/*
* peek into the rates configured in the STA entry.
Expand Down Expand Up @@ -918,10 +919,12 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
set_bit(WL1271_FLAG_STA_RATES_CHANGED, &wl->flags);
}
#endif
wl->tx_queue_count++;
spin_unlock_irqrestore(&wl->wl_lock, flags);

/* queue the packet */
skb_queue_tail(&wl->tx_queue, skb);
q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
skb_queue_tail(&wl->tx_queue[q], skb);

/*
* The chip specific setup must run before the first TX packet -
Expand All @@ -935,7 +938,7 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
* The workqueue is slow to process the tx_queue and we need stop
* the queue here, otherwise the queue will get too long.
*/
if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_HIGH_WATERMARK) {
if (wl->tx_queue_count >= WL1271_TX_QUEUE_HIGH_WATERMARK) {
wl1271_debug(DEBUG_TX, "op_tx: stopping queues");

spin_lock_irqsave(&wl->wl_lock, flags);
Expand Down Expand Up @@ -2719,7 +2722,8 @@ struct ieee80211_hw *wl1271_alloc_hw(void)
wl->hw = hw;
wl->plat_dev = plat_dev;

skb_queue_head_init(&wl->tx_queue);
for (i = 0; i < NUM_TX_QUEUES; i++)
skb_queue_head_init(&wl->tx_queue[i]);

INIT_DELAYED_WORK(&wl->elp_work, wl1271_elp_work);
INIT_DELAYED_WORK(&wl->pspoll_work, wl1271_pspoll_work);
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60 changes: 49 additions & 11 deletions drivers/net/wireless/wl12xx/tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -125,7 +125,6 @@ static void wl1271_tx_fill_hdr(struct wl1271 *wl, struct sk_buff *skb,
/* queue (we use same identifiers for tid's and ac's */
ac = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
desc->tid = ac;

desc->aid = TX_HW_DEFAULT_AID;
desc->reserved = 0;

Expand Down Expand Up @@ -228,7 +227,7 @@ static void handle_tx_low_watermark(struct wl1271 *wl)
unsigned long flags;

if (test_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags) &&
skb_queue_len(&wl->tx_queue) <= WL1271_TX_QUEUE_LOW_WATERMARK) {
wl->tx_queue_count <= WL1271_TX_QUEUE_LOW_WATERMARK) {
/* firmware buffer has space, restart queues */
spin_lock_irqsave(&wl->wl_lock, flags);
ieee80211_wake_queues(wl->hw);
Expand All @@ -237,6 +236,43 @@ static void handle_tx_low_watermark(struct wl1271 *wl)
}
}

static struct sk_buff *wl1271_skb_dequeue(struct wl1271 *wl)
{
struct sk_buff *skb = NULL;
unsigned long flags;

skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_VO]);
if (skb)
goto out;
skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_VI]);
if (skb)
goto out;
skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_BE]);
if (skb)
goto out;
skb = skb_dequeue(&wl->tx_queue[CONF_TX_AC_BK]);

out:
if (skb) {
spin_lock_irqsave(&wl->wl_lock, flags);
wl->tx_queue_count--;
spin_unlock_irqrestore(&wl->wl_lock, flags);
}

return skb;
}

static void wl1271_skb_queue_head(struct wl1271 *wl, struct sk_buff *skb)
{
unsigned long flags;
int q = wl1271_tx_get_queue(skb_get_queue_mapping(skb));

skb_queue_head(&wl->tx_queue[q], skb);
spin_lock_irqsave(&wl->wl_lock, flags);
wl->tx_queue_count++;
spin_unlock_irqrestore(&wl->wl_lock, flags);
}

void wl1271_tx_work_locked(struct wl1271 *wl)
{
struct sk_buff *skb;
Expand Down Expand Up @@ -270,7 +306,7 @@ void wl1271_tx_work_locked(struct wl1271 *wl)
wl1271_acx_rate_policies(wl);
}

while ((skb = skb_dequeue(&wl->tx_queue))) {
while ((skb = wl1271_skb_dequeue(wl))) {
if (!woken_up) {
ret = wl1271_ps_elp_wakeup(wl, false);
if (ret < 0)
Expand All @@ -284,9 +320,9 @@ void wl1271_tx_work_locked(struct wl1271 *wl)
* Aggregation buffer is full.
* Flush buffer and try again.
*/
skb_queue_head(&wl->tx_queue, skb);
wl1271_skb_queue_head(wl, skb);
wl1271_write(wl, WL1271_SLV_MEM_DATA, wl->aggr_buf,
buf_offset, true);
buf_offset, true);
sent_packets = true;
buf_offset = 0;
continue;
Expand All @@ -295,7 +331,7 @@ void wl1271_tx_work_locked(struct wl1271 *wl)
* Firmware buffer is full.
* Queue back last skb, and stop aggregating.
*/
skb_queue_head(&wl->tx_queue, skb);
wl1271_skb_queue_head(wl, skb);
/* No work left, avoid scheduling redundant tx work */
set_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags);
goto out_ack;
Expand Down Expand Up @@ -440,10 +476,13 @@ void wl1271_tx_reset(struct wl1271 *wl)
struct sk_buff *skb;

/* TX failure */
while ((skb = skb_dequeue(&wl->tx_queue))) {
wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);
ieee80211_tx_status(wl->hw, skb);
for (i = 0; i < NUM_TX_QUEUES; i++) {
while ((skb = skb_dequeue(&wl->tx_queue[i]))) {
wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);
ieee80211_tx_status(wl->hw, skb);
}
}
wl->tx_queue_count = 0;

/*
* Make sure the driver is at a consistent state, in case this
Expand Down Expand Up @@ -472,8 +511,7 @@ void wl1271_tx_flush(struct wl1271 *wl)
mutex_lock(&wl->mutex);
wl1271_debug(DEBUG_TX, "flushing tx buffer: %d",
wl->tx_frames_cnt);
if ((wl->tx_frames_cnt == 0) &&
skb_queue_empty(&wl->tx_queue)) {
if ((wl->tx_frames_cnt == 0) && (wl->tx_queue_count == 0)) {
mutex_unlock(&wl->mutex);
return;
}
Expand Down
3 changes: 2 additions & 1 deletion drivers/net/wireless/wl12xx/wl12xx.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -292,7 +292,8 @@ struct wl1271 {
int session_counter;

/* Frames scheduled for transmission, not handled yet */
struct sk_buff_head tx_queue;
struct sk_buff_head tx_queue[NUM_TX_QUEUES];
int tx_queue_count;

struct work_struct tx_work;

Expand Down

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