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Message-Id: <20190807103059.15270-11-idosch@idosch.org>
Date: Wed, 7 Aug 2019 13:30:59 +0300
From: Ido Schimmel <idosch@...sch.org>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, nhorman@...driver.com, jiri@...lanox.com,
toke@...hat.com, dsahern@...il.com, roopa@...ulusnetworks.com,
nikolay@...ulusnetworks.com, jakub.kicinski@...ronome.com,
andy@...yhouse.net, f.fainelli@...il.com, andrew@...n.ch,
vivien.didelot@...il.com, mlxsw@...lanox.com,
Ido Schimmel <idosch@...lanox.com>
Subject: [PATCH net-next 10/10] drop_monitor: Expose tail drop counter
From: Ido Schimmel <idosch@...lanox.com>
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: Ido Schimmel <idosch@...lanox.com>
---
include/uapi/linux/net_dropmon.h | 10 +++
net/core/drop_monitor.c | 101 +++++++++++++++++++++++++++++++
2 files changed, 111 insertions(+)
diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h
index 8658bcd07e0e..a2d253683237 100644
--- a/include/uapi/linux/net_dropmon.h
+++ b/include/uapi/linux/net_dropmon.h
@@ -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,
};
@@ -79,6 +81,7 @@ 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
@@ -102,4 +105,11 @@ 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
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index c9b68a093e0f..59c57154485c 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -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);
}
@@ -727,6 +736,93 @@ 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)
{
@@ -794,6 +890,10 @@ 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,
@@ -860,6 +960,7 @@ 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;
--
2.21.0
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