From 114cf5802165ee93e3ab461c9c505cd94a08b800 Mon Sep 17 00:00:00 2001
From: Tom Herbert <therbert@google.com>
Date: Mon, 28 Nov 2011 16:33:09 +0000
Subject: bql: Byte queue limits

Networking stack support for byte queue limits, uses dynamic queue
limits library.  Byte queue limits are maintained per transmit queue,
and a dql structure has been added to netdev_queue structure for this
purpose.

Configuration of bql is in the tx-<n> sysfs directory for the queue
under the byte_queue_limits directory.  Configuration includes:
limit_min, bql minimum limit
limit_max, bql maximum limit
hold_time, bql slack hold time

Also under the directory are:
limit, current byte limit
inflight, current number of bytes on the queue

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/netdevice.h | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

(limited to 'include/linux')

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9b24cc7a54d1..97edb3215a5a 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -43,6 +43,7 @@
 #include <linux/rculist.h>
 #include <linux/dmaengine.h>
 #include <linux/workqueue.h>
+#include <linux/dynamic_queue_limits.h>
 
 #include <linux/ethtool.h>
 #include <net/net_namespace.h>
@@ -541,7 +542,6 @@ struct netdev_queue {
  */
 	struct net_device	*dev;
 	struct Qdisc		*qdisc;
-	unsigned long		state;
 	struct Qdisc		*qdisc_sleeping;
 #ifdef CONFIG_SYSFS
 	struct kobject		kobj;
@@ -564,6 +564,12 @@ struct netdev_queue {
 	 * (/sys/class/net/DEV/Q/trans_timeout)
 	 */
 	unsigned long		trans_timeout;
+
+	unsigned long		state;
+
+#ifdef CONFIG_BQL
+	struct dql		dql;
+#endif
 } ____cacheline_aligned_in_smp;
 
 static inline int netdev_queue_numa_node_read(const struct netdev_queue *q)
@@ -1862,6 +1868,15 @@ static inline int netif_xmit_frozen_or_stopped(const struct netdev_queue *dev_qu
 static inline void netdev_tx_sent_queue(struct netdev_queue *dev_queue,
 					unsigned int bytes)
 {
+#ifdef CONFIG_BQL
+	dql_queued(&dev_queue->dql, bytes);
+	if (unlikely(dql_avail(&dev_queue->dql) < 0)) {
+		set_bit(__QUEUE_STATE_STACK_XOFF, &dev_queue->state);
+		if (unlikely(dql_avail(&dev_queue->dql) >= 0))
+			clear_bit(__QUEUE_STATE_STACK_XOFF,
+			    &dev_queue->state);
+	}
+#endif
 }
 
 static inline void netdev_sent_queue(struct net_device *dev, unsigned int bytes)
@@ -1872,6 +1887,18 @@ static inline void netdev_sent_queue(struct net_device *dev, unsigned int bytes)
 static inline void netdev_tx_completed_queue(struct netdev_queue *dev_queue,
 					     unsigned pkts, unsigned bytes)
 {
+#ifdef CONFIG_BQL
+	if (likely(bytes)) {
+		dql_completed(&dev_queue->dql, bytes);
+		if (unlikely(test_bit(__QUEUE_STATE_STACK_XOFF,
+		    &dev_queue->state) &&
+		    dql_avail(&dev_queue->dql) >= 0)) {
+			if (test_and_clear_bit(__QUEUE_STATE_STACK_XOFF,
+			     &dev_queue->state))
+				netif_schedule_queue(dev_queue);
+		}
+	}
+#endif
 }
 
 static inline void netdev_completed_queue(struct net_device *dev,
@@ -1882,6 +1909,9 @@ static inline void netdev_completed_queue(struct net_device *dev,
 
 static inline void netdev_tx_reset_queue(struct netdev_queue *q)
 {
+#ifdef CONFIG_BQL
+	dql_reset(&q->dql);
+#endif
 }
 
 static inline void netdev_reset_queue(struct net_device *dev_queue)
-- 
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