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Commit 114cf580 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

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: default avatarTom Herbert <therbert@google.com>
Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 927fbec1

include/linux/netdevice.h

+31 −1
Original line number Diff line number Diff line
@@ -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)

net/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -239,6 +239,12 @@ config NETPRIO_CGROUP 
	  Cgroup subsystem for use in assigning processes to network priorities on

	  a per-interface basis



config BQL

	boolean

	depends on SYSFS

	select DQL

	default y



config HAVE_BPF_JIT

	bool

net/core/dev.c

+3 −0
Original line number Diff line number Diff line
@@ -5470,6 +5470,9 @@ static void netdev_init_one_queue(struct net_device *dev, 
	queue->xmit_lock_owner = -1;

	netdev_queue_numa_node_write(queue, NUMA_NO_NODE);

	queue->dev = dev;

#ifdef CONFIG_BQL

	dql_init(&queue->dql, HZ);

#endif

}



static int netif_alloc_netdev_queues(struct net_device *dev)

net/core/net-sysfs.c

+132 −8
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/wireless.h>

#include <linux/vmalloc.h>

#include <linux/export.h>

#include <linux/jiffies.h>

#include <net/wext.h>



#include "net-sysfs.h"
@@ -845,6 +846,116 @@ static ssize_t show_trans_timeout(struct netdev_queue *queue, 
static struct netdev_queue_attribute queue_trans_timeout =

	__ATTR(tx_timeout, S_IRUGO, show_trans_timeout, NULL);



#ifdef CONFIG_BQL

/*

 * Byte queue limits sysfs structures and functions.

 */

static ssize_t bql_show(char *buf, unsigned int value)

{

	return sprintf(buf, "%u\n", value);

}



static ssize_t bql_set(const char *buf, const size_t count,

		       unsigned int *pvalue)

{

	unsigned int value;

	int err;



	if (!strcmp(buf, "max") || !strcmp(buf, "max\n"))

		value = DQL_MAX_LIMIT;

	else {

		err = kstrtouint(buf, 10, &value);

		if (err < 0)

			return err;

		if (value > DQL_MAX_LIMIT)

			return -EINVAL;

	}



	*pvalue = value;



	return count;

}



static ssize_t bql_show_hold_time(struct netdev_queue *queue,

				  struct netdev_queue_attribute *attr,

				  char *buf)

{

	struct dql *dql = &queue->dql;



	return sprintf(buf, "%u\n", jiffies_to_msecs(dql->slack_hold_time));

}



static ssize_t bql_set_hold_time(struct netdev_queue *queue,

				 struct netdev_queue_attribute *attribute,

				 const char *buf, size_t len)

{

	struct dql *dql = &queue->dql;

	unsigned value;

	int err;



	err = kstrtouint(buf, 10, &value);

	if (err < 0)

		return err;



	dql->slack_hold_time = msecs_to_jiffies(value);



	return len;

}



static struct netdev_queue_attribute bql_hold_time_attribute =

	__ATTR(hold_time, S_IRUGO | S_IWUSR, bql_show_hold_time,

	    bql_set_hold_time);



static ssize_t bql_show_inflight(struct netdev_queue *queue,

				 struct netdev_queue_attribute *attr,

				 char *buf)

{

	struct dql *dql = &queue->dql;



	return sprintf(buf, "%u\n", dql->num_queued - dql->num_completed);

}



static struct netdev_queue_attribute bql_inflight_attribute =

	__ATTR(inflight, S_IRUGO | S_IWUSR, bql_show_inflight, NULL);



#define BQL_ATTR(NAME, FIELD)						\

static ssize_t bql_show_ ## NAME(struct netdev_queue *queue,		\

				 struct netdev_queue_attribute *attr,	\

				 char *buf)				\

{									\

	return bql_show(buf, queue->dql.FIELD);				\

}									\

									\

static ssize_t bql_set_ ## NAME(struct netdev_queue *queue,		\

				struct netdev_queue_attribute *attr,	\

				const char *buf, size_t len)		\

{									\

	return bql_set(buf, len, &queue->dql.FIELD);			\

}									\

									\

static struct netdev_queue_attribute bql_ ## NAME ## _attribute =	\

	__ATTR(NAME, S_IRUGO | S_IWUSR, bql_show_ ## NAME,		\

	    bql_set_ ## NAME);



BQL_ATTR(limit, limit)

BQL_ATTR(limit_max, max_limit)

BQL_ATTR(limit_min, min_limit)



static struct attribute *dql_attrs[] = {

	&bql_limit_attribute.attr,

	&bql_limit_max_attribute.attr,

	&bql_limit_min_attribute.attr,

	&bql_hold_time_attribute.attr,

	&bql_inflight_attribute.attr,

	NULL

};



static struct attribute_group dql_group = {

	.name  = "byte_queue_limits",

	.attrs  = dql_attrs,

};

#endif /* CONFIG_BQL */



#ifdef CONFIG_XPS

static inline unsigned int get_netdev_queue_index(struct netdev_queue *queue)

{
@@ -1096,17 +1207,17 @@ static struct attribute *netdev_queue_default_attrs[] = { 
	NULL

};



#ifdef CONFIG_XPS

static void netdev_queue_release(struct kobject *kobj)

{

	struct netdev_queue *queue = to_netdev_queue(kobj);



#ifdef CONFIG_XPS

	xps_queue_release(queue);

#endif



	memset(kobj, 0, sizeof(*kobj));

	dev_put(queue->dev);

}

#endif /* CONFIG_XPS */



static struct kobj_type netdev_queue_ktype = {

	.sysfs_ops = &netdev_queue_sysfs_ops,
@@ -1125,14 +1236,21 @@ static int netdev_queue_add_kobject(struct net_device *net, int index) 
	kobj->kset = net->queues_kset;

	error = kobject_init_and_add(kobj, &netdev_queue_ktype, NULL,

	    "tx-%u", index);

	if (error) {

		kobject_put(kobj);

		return error;

	}

	if (error)

		goto exit;



#ifdef CONFIG_BQL

	error = sysfs_create_group(kobj, &dql_group);

	if (error)

		goto exit;

#endif



	kobject_uevent(kobj, KOBJ_ADD);

	dev_hold(queue->dev);



	return 0;

exit:

	kobject_put(kobj);

	return error;

}

#endif /* CONFIG_SYSFS */
@@ -1152,8 +1270,14 @@ netdev_queue_update_kobjects(struct net_device *net, int old_num, int new_num) 
		}

	}



	while (--i >= new_num)

		kobject_put(&net->_tx[i].kobj);

	while (--i >= new_num) {

		struct netdev_queue *queue = net->_tx + i;



#ifdef CONFIG_BQL

		sysfs_remove_group(&queue->kobj, &dql_group);

#endif

		kobject_put(&queue->kobj);

	}



	return error;

#else