Hi all,
The ovs ran into a problem in our environment: Flow continuous to upcall(can
not generate corresponding megaflow) , because of flow_put_on_pmd failed.
flow configuration:
ciagent-9-:/Images/fzt/ovs # ovs-ofctl show br0
OFPT_FEATURES_REPLY (xid=0x2): dpid:000070c7f2cb5874
n_tables:254, n_buffers:0
capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
actions: output enqueue ext_action set_vlan_vid set_vlan_pcp strip_vlan
mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
1(bond0): addr:70:c7:f2:cb:58:74
config: 0
state: 0
current: 10GB-FD
speed: 10000 Mbps now, 0 Mbps max
2(test): addr:52:ec:0b:03:38:ab
config: 0
state: 0
current: 10MB-FD COPPER
speed: 10 Mbps now, 0 Mbps max
LOCAL(br0): addr:70:c7:f2:cb:58:74
config: 0
state: 0
current: 10MB-FD COPPER
speed: 10 Mbps now, 0 Mbps max
ciagent-9-:/Images/fzt/ovs # ovs-ofctl dump-flows br0
cookie=0x0, duration=395.501s, table=0, n_packets=717, n_bytes=70266,
priority=28,ip,in_port=bond0 actions=IN_PORT
cookie=0x0, duration=2015.547s, table=0, n_packets=0, n_bytes=0,
priority=29,ip,nw_dst=198.159.208.0/24 actions=output:test
cookie=0x0, duration=2.763s, table=0, n_packets=0, n_bytes=0,
priority=29,ip,nw_dst=139.159.208.0/24 actions=output:test
Steps to reproduce the problem:
Step1:
Generate an ip stream into bond,
SIP：1.2.1.2 DIP：130.119.101.60 Type:icmp request
A megaflow will be generated:
recirc_id(0),in_port(2),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=130.119.101.60/248.0.0.0,frag=no),
packets:751, bytes:73598, used:0.730s, actions:2
Step2:
Delete the flow of “nw_dst=139.159.208.0/24”
ovs-ofctl del-flows br0 "table=0,ip,nw_dst=139.159.208.0/24"
Note: The megaflow of 130.119.101.60 will not be changed.
Step3:
Generate another ip stream into bond,
SIP：1.2.1.2 DIP：168.119.102.61 Type:icmp request
Now, We can find that this stream cannot generate the corresponding megaflow.
It will keep upcalling, and the miss counter in “ovs-appctl dpctl/show” will
keep increasing. If we open the dpif’s debug, can find continuous log of “File
exist”.
Root cause analysis:
The key to lookup cls in fast_path_processing(-->dp_netdev_pmd_lookup_flow) is
different from the one in flow_put_on_pmd(-->dp_netdev_pmd_lookup_flow).
Is there any suggestion to fix this bug? How about the following two
modifications:
1. Use the same key to lookup cls in handler thread
---
lib/dpif-netdev.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index e456cc9..facb9f6 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -3524,10 +3524,12 @@ dpif_netdev_flow_put(struct dpif *dpif, const struct
dpif_flow_put *put)
}
/* Must produce a netdev_flow_key for lookup.
- * Use the same method as employed to create the key when adding
- * the flow to the dplcs to make sure they match. */
- netdev_flow_mask_init(&mask, &match);
- netdev_flow_key_init_masked(&key, &match.flow, &mask);
+ * Must generate key by flow to guarantee that key is the same as the
key in
+ * fast_path_processing().
+ * ps: key.hash will not be used in lookup. */
+ miniflow_map_init(&key.mf, &match->flow);
+ miniflow_init(&key.mf, &match->flow);
+ key.len = netdev_flow_key_size(miniflow_n_values(&key.mf));
if (put->pmd_id == PMD_ID_NULL) {
if (cmap_count(&dp->poll_threads) == 0) {
--
2. Modify the revalidate_ukey__ to delete the megaflow when mask changes
From c7bda1680832a18946b8459f6b937d62b02d0280 Mon Sep 17 00:00:00 2001
From: f00448292 <[email protected]<mailto:[email protected]>>
Date: Mon, 20 Jul 2020 14:44:34 +0800
Subject: [PATCH] NEW
Signed-off-by: f00448292 <[email protected]<mailto:[email protected]>>
---
ofproto/ofproto-dpif-upcall.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
index 8dfa05b..8a8c233 100644
--- a/ofproto/ofproto-dpif-upcall.c
+++ b/ofproto/ofproto-dpif-upcall.c
@@ -2209,7 +2209,7 @@ revalidate_ukey__(struct udpif *udpif, const struct
udpif_key *ukey,
* tells that the datapath flow is now too generic and must be narrowed
* down. Note that we do not know if the datapath has ignored any of the
* wildcarded bits, so we may be overly conservative here. */
- if (flow_wildcards_has_extra(&dp_mask, ctx.wc)) {
+ if (flow_wildcards_equal(&dp_mask, ctx.wc)) {
goto exit;
}
--
Looking forward to your reply.
Thanks.
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