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Date: Fri, 01 Feb 2008 15:58:49 -0800
From: Auke Kok <auke-jan.h.kok@...el.com>
To: jeff@...zik.org
Cc: netdev@...r.kernel.org, e1000-devel@...ts.sourceforge.net
Subject: [PATCH 2/8] ixbge: remove TX lock and redo TX accounting.
From: Ayyappan Veeraiyan <ayyappan.veeraiyan@...el.com>
This ports Herbert Xu's "maybe_stop_tx" code and removes the tx_lock
which is not needed.
Signed-off-by: Ayyappan Veeraiyan <ayyappan.veeraiyan@...el.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@...el.com>
---
drivers/net/ixgbe/ixgbe.h | 2 -
drivers/net/ixgbe/ixgbe_main.c | 110 ++++++++++++++++++++++++++++------------
2 files changed, 76 insertions(+), 36 deletions(-)
diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h
index 7dd9a03..d0bf206 100644
--- a/drivers/net/ixgbe/ixgbe.h
+++ b/drivers/net/ixgbe/ixgbe.h
@@ -136,8 +136,6 @@ struct ixgbe_ring {
u16 head;
u16 tail;
- /* To protect race between sender and clean_tx_irq */
- spinlock_t tx_lock;
struct ixgbe_queue_stats stats;
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 28bb203..b4c9c77 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -165,6 +165,15 @@ static inline bool ixgbe_check_tx_hang(struct ixgbe_adapter *adapter,
return false;
}
+#define IXGBE_MAX_TXD_PWR 14
+#define IXGBE_MAX_DATA_PER_TXD (1 << IXGBE_MAX_TXD_PWR)
+
+/* Tx Descriptors needed, worst case */
+#define TXD_USE_COUNT(S) (((S) >> IXGBE_MAX_TXD_PWR) + \
+ (((S) & (IXGBE_MAX_DATA_PER_TXD - 1)) ? 1 : 0))
+#define DESC_NEEDED (TXD_USE_COUNT(IXGBE_MAX_DATA_PER_TXD) /* skb->data */ + \
+ MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1) /* for context */
+
/**
* ixgbe_clean_tx_irq - Reclaim resources after transmit completes
* @adapter: board private structure
@@ -177,18 +186,34 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter,
struct ixgbe_tx_buffer *tx_buffer_info;
unsigned int i, eop;
bool cleaned = false;
- int count = 0;
+ unsigned int total_tx_bytes = 0, total_tx_packets = 0;
i = tx_ring->next_to_clean;
eop = tx_ring->tx_buffer_info[i].next_to_watch;
eop_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop);
while (eop_desc->wb.status & cpu_to_le32(IXGBE_TXD_STAT_DD)) {
- for (cleaned = false; !cleaned;) {
+ cleaned = false;
+ while (!cleaned) {
tx_desc = IXGBE_TX_DESC_ADV(*tx_ring, i);
tx_buffer_info = &tx_ring->tx_buffer_info[i];
cleaned = (i == eop);
tx_ring->stats.bytes += tx_buffer_info->length;
+ if (cleaned) {
+ struct sk_buff *skb = tx_buffer_info->skb;
+#ifdef NETIF_F_TSO
+ unsigned int segs, bytecount;
+ segs = skb_shinfo(skb)->gso_segs ?: 1;
+ /* multiply data chunks by size of headers */
+ bytecount = ((segs - 1) * skb_headlen(skb)) +
+ skb->len;
+ total_tx_packets += segs;
+ total_tx_bytes += bytecount;
+#else
+ total_tx_packets++;
+ total_tx_bytes += skb->len;
+#endif
+ }
ixgbe_unmap_and_free_tx_resource(adapter,
tx_buffer_info);
tx_desc->wb.status = 0;
@@ -204,29 +229,34 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter,
eop_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop);
/* weight of a sort for tx, avoid endless transmit cleanup */
- if (count++ >= tx_ring->work_limit)
+ if (total_tx_packets >= tx_ring->work_limit)
break;
}
tx_ring->next_to_clean = i;
-#define TX_WAKE_THRESHOLD 32
- spin_lock(&tx_ring->tx_lock);
-
- if (cleaned && netif_carrier_ok(netdev) &&
- (IXGBE_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD) &&
- !test_bit(__IXGBE_DOWN, &adapter->state))
- netif_wake_queue(netdev);
-
- spin_unlock(&tx_ring->tx_lock);
+#define TX_WAKE_THRESHOLD (DESC_NEEDED * 2)
+ if (total_tx_packets && netif_carrier_ok(netdev) &&
+ (IXGBE_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD)) {
+ /* Make sure that anybody stopping the queue after this
+ * sees the new next_to_clean.
+ */
+ smp_mb();
+ if (netif_queue_stopped(netdev) &&
+ !test_bit(__IXGBE_DOWN, &adapter->state)) {
+ netif_wake_queue(netdev);
+ adapter->restart_queue++;
+ }
+ }
if (adapter->detect_tx_hung)
if (ixgbe_check_tx_hang(adapter, tx_ring, eop, eop_desc))
netif_stop_queue(netdev);
- if (count >= tx_ring->work_limit)
+ if (total_tx_packets >= tx_ring->work_limit)
IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS, tx_ring->eims_value);
+ cleaned = total_tx_packets ? true : false;
return cleaned;
}
@@ -1646,7 +1676,6 @@ int ixgbe_setup_tx_resources(struct ixgbe_adapter *adapter,
txdr->next_to_use = 0;
txdr->next_to_clean = 0;
txdr->work_limit = txdr->count;
- spin_lock_init(&txdr->tx_lock);
return 0;
}
@@ -2086,15 +2115,6 @@ static void ixgbe_watchdog(unsigned long data)
round_jiffies(jiffies + 2 * HZ));
}
-#define IXGBE_MAX_TXD_PWR 14
-#define IXGBE_MAX_DATA_PER_TXD (1 << IXGBE_MAX_TXD_PWR)
-
-/* Tx Descriptors needed, worst case */
-#define TXD_USE_COUNT(S) (((S) >> IXGBE_MAX_TXD_PWR) + \
- (((S) & (IXGBE_MAX_DATA_PER_TXD - 1)) ? 1 : 0))
-#define DESC_NEEDED (TXD_USE_COUNT(IXGBE_MAX_DATA_PER_TXD) /* skb->data */ + \
- MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1) /* for context */
-
static int ixgbe_tso(struct ixgbe_adapter *adapter,
struct ixgbe_ring *tx_ring, struct sk_buff *skb,
u32 tx_flags, u8 *hdr_len)
@@ -2366,6 +2386,37 @@ static void ixgbe_tx_queue(struct ixgbe_adapter *adapter,
writel(i, adapter->hw.hw_addr + tx_ring->tail);
}
+static int __ixgbe_maybe_stop_tx(struct net_device *netdev,
+ struct ixgbe_ring *tx_ring, int size)
+{
+ struct ixgbe_adapter *adapter = netdev_priv(netdev);
+
+ netif_stop_queue(netdev);
+ /* Herbert's original patch had:
+ * smp_mb__after_netif_stop_queue();
+ * but since that doesn't exist yet, just open code it. */
+ smp_mb();
+
+ /* We need to check again in a case another CPU has just
+ * made room available. */
+ if (likely(IXGBE_DESC_UNUSED(tx_ring) < size))
+ return -EBUSY;
+
+ /* A reprieve! - use start_queue because it doesn't call schedule */
+ netif_wake_queue(netdev);
+ ++adapter->restart_queue;
+ return 0;
+}
+
+static int ixgbe_maybe_stop_tx(struct net_device *netdev,
+ struct ixgbe_ring *tx_ring, int size)
+{
+ if (likely(IXGBE_DESC_UNUSED(tx_ring) >= size))
+ return 0;
+ return __ixgbe_maybe_stop_tx(netdev, tx_ring, size);
+}
+
+
static int ixgbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
{
struct ixgbe_adapter *adapter = netdev_priv(netdev);
@@ -2373,7 +2424,6 @@ static int ixgbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
unsigned int len = skb->len;
unsigned int first;
unsigned int tx_flags = 0;
- unsigned long flags = 0;
u8 hdr_len;
int tso;
unsigned int mss = 0;
@@ -2399,14 +2449,10 @@ static int ixgbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
for (f = 0; f < nr_frags; f++)
count += TXD_USE_COUNT(skb_shinfo(skb)->frags[f].size);
- spin_lock_irqsave(&tx_ring->tx_lock, flags);
- if (IXGBE_DESC_UNUSED(tx_ring) < (count + 2)) {
+ if (ixgbe_maybe_stop_tx(netdev, tx_ring, count)) {
adapter->tx_busy++;
- netif_stop_queue(netdev);
- spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
return NETDEV_TX_BUSY;
}
- spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
if (adapter->vlgrp && vlan_tx_tag_present(skb)) {
tx_flags |= IXGBE_TX_FLAGS_VLAN;
tx_flags |= (vlan_tx_tag_get(skb) << IXGBE_TX_FLAGS_VLAN_SHIFT);
@@ -2433,11 +2479,7 @@ static int ixgbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
netdev->trans_start = jiffies;
- spin_lock_irqsave(&tx_ring->tx_lock, flags);
- /* Make sure there is space in the ring for the next send. */
- if (IXGBE_DESC_UNUSED(tx_ring) < DESC_NEEDED)
- netif_stop_queue(netdev);
- spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
+ ixgbe_maybe_stop_tx(netdev, tx_ring, DESC_NEEDED);
return NETDEV_TX_OK;
}
--
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