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Commit e9feb580 authored by Ido Schimmel's avatar Ido Schimmel Committed by David S. Miller
Browse files

drop_monitor: Expose tail drop counter 



Previous patch made the length of the per-CPU skb drop list
configurable. Expose a counter that shows how many packets could not be
enqueued to this list.

This allows users determine the desired queue length.

Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 30328d46

include/uapi/linux/net_dropmon.h

+10 −0
Original line number Diff line number Diff line
@@ -56,6 +56,8 @@ enum { 
	NET_DM_CMD_PACKET_ALERT,

	NET_DM_CMD_CONFIG_GET,

	NET_DM_CMD_CONFIG_NEW,

	NET_DM_CMD_STATS_GET,

	NET_DM_CMD_STATS_NEW,

	_NET_DM_CMD_MAX,

};
@@ -80,6 +82,7 @@ enum net_dm_attr { 
	NET_DM_ATTR_TRUNC_LEN,			/* u32 */

	NET_DM_ATTR_ORIG_LEN,			/* u32 */

	NET_DM_ATTR_QUEUE_LEN,			/* u32 */

	NET_DM_ATTR_STATS,			/* nested */



	__NET_DM_ATTR_MAX,

	NET_DM_ATTR_MAX = __NET_DM_ATTR_MAX - 1
@@ -103,4 +106,11 @@ enum { 
	NET_DM_ATTR_PORT_MAX = __NET_DM_ATTR_PORT_MAX - 1

};



enum {

	NET_DM_ATTR_STATS_DROPPED,		/* u64 */



	__NET_DM_ATTR_STATS_MAX,

	NET_DM_ATTR_STATS_MAX = __NET_DM_ATTR_STATS_MAX - 1

};



#endif

net/core/drop_monitor.c

+101 −0
Original line number Diff line number Diff line
@@ -51,12 +51,18 @@ static int trace_state = TRACE_OFF; 
 */

static DEFINE_MUTEX(net_dm_mutex);



struct net_dm_stats {

	u64 dropped;

	struct u64_stats_sync syncp;

};



struct per_cpu_dm_data {

	spinlock_t		lock;	/* Protects 'skb' and 'send_timer' */

	struct sk_buff		*skb;

	struct sk_buff_head	drop_queue;

	struct work_struct	dm_alert_work;

	struct timer_list	send_timer;

	struct net_dm_stats	stats;

};



struct dm_hw_stat_delta {
@@ -300,6 +306,9 @@ static void net_dm_packet_trace_kfree_skb_hit(void *ignore, 


unlock_free:

	spin_unlock_irqrestore(&data->drop_queue.lock, flags);

	u64_stats_update_begin(&data->stats.syncp);

	data->stats.dropped++;

	u64_stats_update_end(&data->stats.syncp);

	consume_skb(nskb);

}
@@ -732,6 +741,93 @@ static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 
	return rc;

}



static void net_dm_stats_read(struct net_dm_stats *stats)

{

	int cpu;



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

	for_each_possible_cpu(cpu) {

		struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);

		struct net_dm_stats *cpu_stats = &data->stats;

		unsigned int start;

		u64 dropped;



		do {

			start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);

			dropped = cpu_stats->dropped;

		} while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));



		stats->dropped += dropped;

	}

}



static int net_dm_stats_put(struct sk_buff *msg)

{

	struct net_dm_stats stats;

	struct nlattr *attr;



	net_dm_stats_read(&stats);



	attr = nla_nest_start(msg, NET_DM_ATTR_STATS);

	if (!attr)

		return -EMSGSIZE;



	if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,

			      stats.dropped, NET_DM_ATTR_PAD))

		goto nla_put_failure;



	nla_nest_end(msg, attr);



	return 0;



nla_put_failure:

	nla_nest_cancel(msg, attr);

	return -EMSGSIZE;

}



static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)

{

	void *hdr;

	int rc;



	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,

			  &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);

	if (!hdr)

		return -EMSGSIZE;



	rc = net_dm_stats_put(msg);

	if (rc)

		goto nla_put_failure;



	genlmsg_end(msg, hdr);



	return 0;



nla_put_failure:

	genlmsg_cancel(msg, hdr);

	return -EMSGSIZE;

}



static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)

{

	struct sk_buff *msg;

	int rc;



	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);

	if (!msg)

		return -ENOMEM;



	rc = net_dm_stats_fill(msg, info);

	if (rc)

		goto free_msg;



	return genlmsg_reply(msg, info);



free_msg:

	nlmsg_free(msg);

	return rc;

}



static int dropmon_net_event(struct notifier_block *ev_block,

			     unsigned long event, void *ptr)

{
@@ -799,6 +895,10 @@ static const struct genl_ops dropmon_ops[] = { 
		.cmd = NET_DM_CMD_CONFIG_GET,

		.doit = net_dm_cmd_config_get,

	},

	{

		.cmd = NET_DM_CMD_STATS_GET,

		.doit = net_dm_cmd_stats_get,

	},

};



static int net_dm_nl_pre_doit(const struct genl_ops *ops,
@@ -865,6 +965,7 @@ static int __init init_net_drop_monitor(void) 
		data = &per_cpu(dm_cpu_data, cpu);

		spin_lock_init(&data->lock);

		skb_queue_head_init(&data->drop_queue);

		u64_stats_init(&data->stats.syncp);

	}



	goto out;