From 2fe30dce08220cb267641dd7dc3a53363f310622 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Thu, 31 Jan 2019 22:39:32 +0100 Subject: [PATCH] mt76: reduce locking in mt76_dma_tx_cleanup q->tail can be safely updated without locking, because there is no concurrent access. If called from outside of the tasklet (for flushing), the tasklet is always disabled. q->queued can be safely read without locking, as long as the decrement happens within the locked section. This patch allows cleaning up tx packets outside of the section that holds the queue lock for improved performance Signed-off-by: Felix Fietkau --- drivers/net/wireless/mediatek/mt76/dma.c | 26 ++++++++++++++++-------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c index 7145b75b6438..e4a5b34915bf 100644 --- a/drivers/net/wireless/mediatek/mt76/dma.c +++ b/drivers/net/wireless/mediatek/mt76/dma.c @@ -149,31 +149,29 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush) struct mt76_sw_queue *sq = &dev->q_tx[qid]; struct mt76_queue *q = sq->q; struct mt76_queue_entry entry; + unsigned int n_swq_queued[4] = {}; + unsigned int n_queued = 0; bool wake = false; - int last; + int i, last; if (!q) return; - spin_lock_bh(&q->lock); if (flush) last = -1; else last = readl(&q->regs->dma_idx); - while (q->queued && q->tail != last) { + while ((q->queued > n_queued) && q->tail != last) { mt76_dma_tx_cleanup_idx(dev, q, q->tail, &entry); if (entry.schedule) - dev->q_tx[entry.qid].swq_queued--; + n_swq_queued[entry.qid]++; q->tail = (q->tail + 1) % q->ndesc; - q->queued--; + n_queued++; - if (entry.skb) { - spin_unlock_bh(&q->lock); + if (entry.skb) dev->drv->tx_complete_skb(dev, qid, &entry); - spin_lock_bh(&q->lock); - } if (entry.txwi) { mt76_put_txwi(dev, entry.txwi); @@ -184,6 +182,16 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush) last = readl(&q->regs->dma_idx); } + spin_lock_bh(&q->lock); + + q->queued -= n_queued; + for (i = 0; i < ARRAY_SIZE(n_swq_queued); i++) { + if (!n_swq_queued[i]) + continue; + + dev->q_tx[i].swq_queued -= n_swq_queued[i]; + } + if (flush) mt76_dma_sync_idx(dev, q); -- 2.30.2