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Subject[PATCH v2] openvswitch: Add support to count upall packets
Date
Added the total number of upcalls and the total of upcall failures.
Due to ovs-userspace do not support NLA_NESTED, here still use the
"struct ovs_vport_upcall_stats"

Thank you
wangchuanlei

On 14 Sep 2022, at 14:14, wangchuanlei wrote:

> Add support to count upcall packets on every interface.
> I always encounter high cpu use of ovs-vswictchd, this help to check
> which interface send too many packets without open vlog/set switch,
> and have no influence on datapath.

Hi,

I did not do a full review, but I think we should not try to make the
same mistake as before and embed a structure inside a netlink message.

You are adding “struct ovs_vport_upcall_stats” but in theory,
you could have just added the new entry to “ovs_vport_stats”.
But this is breaking userspace as it expects an exact structure size :(

So I think the right approach would be to have “
OVS_VPORT_ATTR_UPCALL_STATS” be an NLA_NESTED type, and have
individual stat attributes as NLA_U64 (or whatever type you need).

What is also confusing is that you use upcall_packets in
ovs_vport_upcall_stats, which to me are the total of up calls,
but you called it n_missed in your stats. I think you should try to
avoid missed in the upcall path, and just call it n_upcall_packets also.

In addition, I think you should keep two types of statics, and make them
available, namely the total number of upcalls and the total of upcall
failures.

Cheers,

Eelco

Signed-off-by: wangchuanlei <wangchuanlei@inspur.com>
---
include/uapi/linux/openvswitch.h | 6 ++++
net/openvswitch/datapath.c | 54 +++++++++++++++++++++++++++++++-
net/openvswitch/datapath.h | 12 +++++++
net/openvswitch/vport.c | 33 +++++++++++++++++++
net/openvswitch/vport.h | 4 +++
5 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 94066f87e9ee..bb671d92b711 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -126,6 +126,11 @@ struct ovs_vport_stats {
__u64 tx_dropped; /* no space available in linux */
};

+struct ovs_vport_upcall_stats {
+ __u64 upcall_success; /* total packets upcalls succeed */
+ __u64 upcall_fail; /* total packets upcalls failed */
+};
+
/* Allow last Netlink attribute to be unaligned */
#define OVS_DP_F_UNALIGNED (1 << 0)

@@ -277,6 +282,7 @@ enum ovs_vport_attr {
OVS_VPORT_ATTR_PAD,
OVS_VPORT_ATTR_IFINDEX,
OVS_VPORT_ATTR_NETNSID,
+ OVS_VPORT_ATTR_UPCALL_STATS, /* struct ovs_vport_upcall_stats */
__OVS_VPORT_ATTR_MAX
};

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index c8a9075ddd0a..8b8ea95f94ae 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -209,6 +209,28 @@ static struct vport *new_vport(const struct vport_parms *parms)
return vport;
}

+static void ovs_vport_upcalls(struct sk_buff *skb,
+ const struct dp_upcall_info *upcall_info,
+ bool upcall_success)
+{
+ if (upcall_info->cmd == OVS_PACKET_CMD_MISS ||
+ upcall_info->cmd == OVS_PACKET_CMD_ACTION) {
+ const struct vport *p = OVS_CB(skb)->input_vport;
+ struct vport_upcall_stats_percpu *vport_stats;
+ u64 *stats_counter_upcall;
+
+ vport_stats = this_cpu_ptr(p->vport_upcall_stats_percpu);
+ if (upcall_success)
+ stats_counter_upcall = &vport_stats->n_upcall_success;
+ else
+ stats_counter_upcall = &vport_stats->n_upcall_fail;
+
+ u64_stats_update_begin(&vport_stats->syncp);
+ (*stats_counter_upcall)++;
+ u64_stats_update_end(&vport_stats->syncp);
+ }
+}
+
void ovs_dp_detach_port(struct vport *p)
{
ASSERT_OVSL();
@@ -216,6 +238,9 @@ void ovs_dp_detach_port(struct vport *p)
/* First drop references to device. */
hlist_del_rcu(&p->dp_hash_node);

+ /* Free percpu memory */
+ free_percpu(p->vport_upcall_stats_percpu);
+
/* Then destroy it. */
ovs_vport_del(p);
}
@@ -305,8 +330,12 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen);
else
err = queue_gso_packets(dp, skb, key, upcall_info, cutlen);
- if (err)
+ if (err) {
+ ovs_vport_upcalls(skb, upcall_info, false);
goto err;
+ } else {
+ ovs_vport_upcalls(skb, upcall_info, true);
+ }

return 0;

@@ -1825,6 +1854,13 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
goto err_destroy_portids;
}

+ vport->vport_upcall_stats_percpu =
+ netdev_alloc_pcpu_stats(struct vport_upcall_stats_percpu);
+ if (!vport->vport_upcall_stats_percpu) {
+ err = -ENOMEM;
+ goto err_destroy_portids;
+ }
+
err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
info->snd_seq, 0, OVS_DP_CMD_NEW);
BUG_ON(err < 0);
@@ -2068,6 +2104,7 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb,
{
struct ovs_header *ovs_header;
struct ovs_vport_stats vport_stats;
+ struct ovs_vport_upcall_stats vport_upcall_stats;
int err;

ovs_header = genlmsg_put(skb, portid, seq, &dp_vport_genl_family,
@@ -2097,6 +2134,13 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb,
OVS_VPORT_ATTR_PAD))
goto nla_put_failure;

+ ovs_vport_get_upcall_stats(vport, &vport_upcall_stats);
+ if (nla_put_64bit(skb, OVS_VPORT_ATTR_UPCALL_STATS,
+ sizeof(struct ovs_vport_upcall_stats),
+ &vport_upcall_stats,
+ OVS_VPORT_ATTR_PAD))
+ goto nla_put_failure;
+
if (ovs_vport_get_upcall_portids(vport, skb))
goto nla_put_failure;

@@ -2278,6 +2322,14 @@ static int ovs_vport_cmd_new(struct sk_buff *skb, struct genl_info *info)
goto exit_unlock_free;
}

+ vport->vport_upcall_stats_percpu =
+ netdev_alloc_pcpu_stats(struct vport_upcall_stats_percpu);
+
+ if (!vport->vport_upcall_stats_percpu) {
+ err = -ENOMEM;
+ goto exit_unlock_free;
+ }
+
err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
info->snd_portid, info->snd_seq, 0,
OVS_VPORT_CMD_NEW, GFP_KERNEL);
diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h
index 0cd29971a907..2f40db78d617 100644
--- a/net/openvswitch/datapath.h
+++ b/net/openvswitch/datapath.h
@@ -50,6 +50,18 @@ struct dp_stats_percpu {
struct u64_stats_sync syncp;
};

+/**
+ * struct vport_upcall_stats_percpu - per-cpu packet upcall statistics for
+ * a given vport.
+ * @n_upcall_success: Number of packets that upcall to userspace succeed.
+ * @n_upcall_fail: Number of packets that upcall to userspace failed.
+ */
+struct vport_upcall_stats_percpu {
+ u64 n_upcall_success;
+ u64 n_upcall_fail;
+ struct u64_stats_sync syncp;
+};
+
/**
* struct dp_nlsk_pids - array of netlink portids of for a datapath.
* This is used when OVS_DP_F_DISPATCH_UPCALL_PER_CPU
diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index 82a74f998966..39b018da685e 100644
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c
@@ -284,6 +284,39 @@ void ovs_vport_get_stats(struct vport *vport, struct ovs_vport_stats *stats)
stats->tx_packets = dev_stats->tx_packets;
}

+/**
+ * ovs_vport_get_upcall_stats - retrieve upcall stats
+ *
+ * @vport: vport from which to retrieve the stats
+ * @ovs_vport_upcall_stats: location to store stats
+ *
+ * Retrieves upcall stats for the given device.
+ *
+ * Must be called with ovs_mutex or rcu_read_lock.
+ */
+void ovs_vport_get_upcall_stats(struct vport *vport, struct ovs_vport_upcall_stats *stats)
+{
+ int i;
+
+ stats->upcall_success = 0;
+ stats->upcall_fail = 0;
+
+ for_each_possible_cpu(i) {
+ const struct vport_upcall_stats_percpu *percpu_upcall_stats;
+ struct vport_upcall_stats_percpu local_stats;
+ unsigned int start;
+
+ percpu_upcall_stats = per_cpu_ptr(vport->vport_upcall_stats_percpu, i);
+ do {
+ start = u64_stats_fetch_begin_irq(&percpu_upcall_stats->syncp);
+ local_stats = *percpu_upcall_stats;
+ } while (u64_stats_fetch_retry_irq(&percpu_upcall_stats->syncp, start));
+
+ stats->upcall_success += local_stats.n_upcall_success;
+ stats->upcall_fail += local_stats.n_upcall_fail;
+ }
+}
+
/**
* ovs_vport_get_options - retrieve device options
*
diff --git a/net/openvswitch/vport.h b/net/openvswitch/vport.h
index 7d276f60c000..6defacd6d718 100644
--- a/net/openvswitch/vport.h
+++ b/net/openvswitch/vport.h
@@ -32,6 +32,9 @@ struct vport *ovs_vport_locate(const struct net *net, const char *name);

void ovs_vport_get_stats(struct vport *, struct ovs_vport_stats *);

+void ovs_vport_get_upcall_stats(struct vport *vport,
+ struct ovs_vport_upcall_stats *stats);
+
int ovs_vport_set_options(struct vport *, struct nlattr *options);
int ovs_vport_get_options(const struct vport *, struct sk_buff *);

@@ -78,6 +81,7 @@ struct vport {
struct hlist_node hash_node;
struct hlist_node dp_hash_node;
const struct vport_ops *ops;
+ struct vport_upcall_stats_percpu __percpu *vport_upcall_stats_percpu;

struct list_head detach_list;
struct rcu_head rcu;
--
2.27.0
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