ofctrl: Wait at S_WAIT_BEFORE_CLEAR only once.

The ovn-ofctrl-wait-before-clear setting is designed to minimize downtime during the initial start-up of the ovn-controller. For this purpose, the ovn-controller should wait only once upon entering the S_WAIT_BEFORE_CLEAR state for the first time. Subsequent reconnections to the OVS, such as those occurring during an OVS restart/upgrade, should not trigger this wait. However, the current implemention always waits for the configured time in the S_WAIT_BEFORE_CLEAR state, which can inadvertently delay flow installations during OVS restart/upgrade, potentially causing more harm than good. (The extent of the impact varies based on the method used to restart OVS, including whether flow save/restore tools and the flow-restore-wait feature are employed.) This patch avoids the unnecessary wait after the initial one. Fixes: 896adfd ("ofctrl: Support ovn-ofctrl-wait-before-clear to reduce down time during upgrade.") Signed-off-by: Han Zhou <[email protected]> Acked-by: Mark Michelson <[email protected]>
hzhou8 · Apr 3, 2024 · bbf2f94 · bbf2f94
1 parent 8bad19c
commit bbf2f94
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/controller/ofctrl.c b/controller/ofctrl.c
@@ -634,7 +634,6 @@ run_S_WAIT_BEFORE_CLEAR(void)
     if (!wait_before_clear_time ||
         (wait_before_clear_expire &&
          time_msec() >= wait_before_clear_expire)) {
-        wait_before_clear_expire = 0;
         state = S_CLEAR_FLOWS;
         return;
     }

diff --git a/tests/ovn-controller.at b/tests/ovn-controller.at
@@ -2324,10 +2324,15 @@ lflow_run_2=$(ovn-appctl -t ovn-controller coverage/read-counter lflow_run)
 AT_CHECK_UNQUOTED([echo $lflow_run_1], [0], [$lflow_run_2
 ])
 
-# Restart OVS this time, and wait until flows are reinstalled
+# Restart OVS this time. Flows should be reinstalled without waiting.
 OVS_APP_EXIT_AND_WAIT([ovs-vswitchd])
 start_daemon ovs-vswitchd --enable-dummy=system -vvconn -vofproto_dpif -vunixctl
-OVS_WAIT_UNTIL([ovs-ofctl dump-flows br-int | grep -F 10.1.2.4 | grep -vF 2.2.2.2])
+
+# Sync to make sure ovn-controller is given enough time to install the flows.
+check ovn-nbctl --wait=hv sync
+
+# Flow should be installed without any extra waiting.
+AT_CHECK([ovs-ofctl dump-flows br-int | grep -F 10.1.2.4 | grep -vF 2.2.2.2], [0], [ignore])
 
 check ovn-nbctl --wait=hv lb-add lb3 3.3.3.3 10.1.2.5 \
 -- ls-lb-add ls1 lb3