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Date: Thu, 31 Jan 2013 19:36:26 +0530
From: Vipul Pandya <vipul@...lsio.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, divy@...lsio.com, dm@...lsio.com,
leedom@...lsio.com, abhishek@...lsio.com,
Vipul Pandya <vipul@...lsio.com>,
Jay Hernandez <jay@...lsio.com>
Subject: [PATCH net-next 1/2] cxgb4: Send Flush Work Request on a TX Queue
Send Flush Work Request on a TX Queue if it has unreclaimed TX Descriptors
and the last time anything was sent on the associated net device was more than
5 seconds in the past, issue a flush request on the TX Queue in order to get
any stranded skb's off the TX Queue.
Signed-off-by: Jay Hernandez <jay@...lsio.com>
Signed-off-by: Vipul Pandya <vipul@...lsio.com>
---
drivers/net/ethernet/chelsio/cxgb4/sge.c | 112 +++++++++++++++++++++++--
drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h | 8 ++
2 files changed, 113 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c
index fe9a2ea..d6cfdd5 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -1994,6 +1994,81 @@ static void sge_rx_timer_cb(unsigned long data)
mod_timer(&s->rx_timer, jiffies + RX_QCHECK_PERIOD);
}
+/* send_flush_wr - send a Flush Work Request on a TX Queue
+ * @adapter: the adapter
+ * @txq: TX Queue to flush
+ *
+ * Send a Flush Work Request on the indicated TX Queue with a request to
+ * updated the Status Page of the TX Queue when the Flush Work Request
+ * is processed. This will allow us to determine when all of the
+ * preceeding TX Requests have been processed.
+ */
+static void send_flush_wr(struct adapter *adapter, struct sge_eth_txq *txq)
+{
+ int credits;
+ unsigned int ndesc;
+ struct fw_eq_flush_wr *fwr;
+ struct sk_buff *skb;
+ unsigned int len;
+
+ /* See if there's space in the TX Queue to fit the Flush Work Request.
+ * If not, we simply return.
+ */
+ len = sizeof(*fwr);
+ ndesc = DIV_ROUND_UP(len, sizeof(struct tx_desc));
+ credits = txq_avail(&txq->q) - ndesc;
+ if (unlikely(credits < 0))
+ return;
+
+ /* Allocate an skb to hold the Flush Work Request and initialize it
+ * with the flush request.
+ */
+ skb = alloc_skb(len, GFP_ATOMIC);
+ if (unlikely(!skb))
+ return;
+ fwr = (struct fw_eq_flush_wr *)__skb_put(skb, len);
+ memset(fwr, 0, sizeof(*fwr));
+
+ fwr->opcode = (__force __u8) htonl(FW_WR_OP(FW_EQ_FLUSH_WR));
+ fwr->equiq_to_len16 = cpu_to_be32(FW_WR_EQUEQ |
+ FW_WR_LEN16(len / 16));
+
+ /* If the Flush Work Request fills up the TX Queue to the point where
+ * we don't have enough room for a maximum sized TX Request, then
+ * we need to stop further TX Requests and request that the firmware
+ * notify us with an interrupt when it processes this request.
+ */
+ if (unlikely(credits < ETHTXQ_STOP_THRES)) {
+ eth_txq_stop(txq);
+ fwr->equiq_to_len16 |= cpu_to_be32(FW_WR_EQUIQ);
+ }
+
+ /* Copy the Flush Work Request into the TX Queue and notify the
+ * hardware that we've given it some more to do ...
+ */
+ inline_tx_skb(skb, &txq->q, &txq->q.desc[txq->q.pidx]);
+ txq_advance(&txq->q, ndesc);
+ ring_tx_db(adapter, &txq->q, ndesc);
+
+ /* Free up the skb and return ...
+ */
+ kfree_skb(skb);
+ return;
+}
+
+/* sge_tx_timer_cb - perform periodic maintenance of SGE Tx queues
+ * @data: the adapter
+ *
+ * Runs periodically from a timer to perform maintenance of SGE Tx queues.
+ * It performs two tasks:
+ *
+ * a) Restarts offload Tx queues stopped due to I/O MMU mapping errors.
+ *
+ * b) Reclaims completed Tx packets for the Ethernet queues. Normally
+ * packets are cleaned up by new Tx packets, this timer cleans up packets
+ * when no new packets are being submitted. This is essential for pktgen,
+ * at least.
+ */
static void sge_tx_timer_cb(unsigned long data)
{
unsigned long m;
@@ -2015,26 +2090,49 @@ static void sge_tx_timer_cb(unsigned long data)
do {
struct sge_eth_txq *q = &s->ethtxq[i];
- if (q->q.in_use &&
- time_after_eq(jiffies, q->txq->trans_start + HZ / 100) &&
- __netif_tx_trylock(q->txq)) {
- int avail = reclaimable(&q->q);
+ if (__netif_tx_trylock(q->txq)) {
- if (avail) {
+ if (reclaimable(&q->q)) {
+ int avail = reclaimable(&q->q);
if (avail > budget)
avail = budget;
free_tx_desc(adap, &q->q, avail, true);
q->q.in_use -= avail;
+
budget -= avail;
+ if (!budget) {
+ __netif_tx_unlock(q->txq);
+ break;
+ }
+ }
+
+ /* If the TX Queue has unreclaimed TX Descriptors and
+ * the last time anything was sent on the associated
+ * net device was more than 5 seconds in the past,
+ * issue a flush request on the TX Queue in order to
+ * get any stranded skb's off the TX Queue.
+ */
+ if (q->q.in_use > 0 &&
+ time_after(jiffies,
+ q->txq->dev->trans_start + HZ * 5)) {
+ local_bh_disable();
+ send_flush_wr(adap, q);
+ local_bh_enable();
}
__netif_tx_unlock(q->txq);
}
- if (++i >= s->ethqsets)
+ i++;
+ if (i >= s->ethqsets)
i = 0;
- } while (budget && i != s->ethtxq_rover);
+ } while (i != s->ethtxq_rover);
s->ethtxq_rover = i;
+
+ /* If we found too many reclaimable packets schedule a timer in the
+ * near future to continue where we left off. Otherwise the next timer
+ * will be at its normal interval.
+ */
mod_timer(&s->tx_timer, jiffies + (budget ? TX_QCHECK_PERIOD : 2));
}
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h b/drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h
index a0dcccd..db31bd6 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4fw_api.h
@@ -85,6 +85,7 @@ enum fw_wr_opcodes {
FW_ULPTX_WR = 0x04,
FW_TP_WR = 0x05,
FW_ETH_TX_PKT_WR = 0x08,
+ FW_EQ_FLUSH_WR = 0x1b,
FW_OFLD_CONNECTION_WR = 0x2f,
FW_FLOWC_WR = 0x0a,
FW_OFLD_TX_DATA_WR = 0x0b,
@@ -416,6 +417,13 @@ struct fw_eth_tx_pkt_wr {
__be64 r3;
};
+struct fw_eq_flush_wr {
+ __u8 opcode;
+ __u8 r1[3];
+ __be32 equiq_to_len16;
+ __be64 r3;
+};
+
struct fw_ofld_connection_wr {
__be32 op_compl;
__be32 len16_pkd;
--
1.7.1
--
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