northd I-P: Sync SB load balancers in a separate engine node.

Similar to the commit [1], a new sub-engine node "sync_to_sb_lb"
is added with-in the "sync_to_sb" to sync the SB load balancers.
Its main input nodes are "northd" (to access the "lbs" hmap built
by this node) and "sb_load_balancer" to access the SB load balancer.
"sync_to_sb_lb" doesn't add any handlers and falls back to full
recompute all the time.

[1] - ccafcc2("northd I-P: Add a new engine node 'en_sync_to_sb' to sync SB tables.")

Acked-by: Han Zhou <hzhou@ovn.org>
Reviewed-by: Ales Musil <amusil@redhat.com>
Acked-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Numan Siddique <numans@ovn.org>

northd/en-northd.c

@@ -95,8 +95,6 @@ northd_get_input_data(struct engine_node *node,
         EN_OVSDB_GET(engine_get_input("SB_chassis", node));
     input_data->sbrec_fdb_table =
         EN_OVSDB_GET(engine_get_input("SB_fdb", node));
-    input_data->sbrec_load_balancer_table =
-        EN_OVSDB_GET(engine_get_input("SB_load_balancer", node));
     input_data->sbrec_service_monitor_table =
         EN_OVSDB_GET(engine_get_input("SB_service_monitor", node));
     input_data->sbrec_dns_table =

northd/en-sync-sb.c

@@ -201,6 +201,49 @@ sync_to_sb_addr_set_nb_port_group_handler(struct engine_node *node,
     return true;
 }
 
+/* sync_to_sb_lb engine node functions.
+ * This engine node syncs the SB load balancers.
+ */
+void *
+en_sync_to_sb_lb_init(struct engine_node *node OVS_UNUSED,
+                      struct engine_arg *arg OVS_UNUSED)
+{
+    return NULL;
+}
+
+void
+en_sync_to_sb_lb_run(struct engine_node *node, void *data OVS_UNUSED)
+{
+    const struct sbrec_load_balancer_table *sb_load_balancer_table =
+        EN_OVSDB_GET(engine_get_input("SB_load_balancer", node));
+    const struct engine_context *eng_ctx = engine_get_context();
+    struct northd_data *northd_data = engine_get_input_data("northd", node);
+
+    sync_lbs(eng_ctx->ovnsb_idl_txn, sb_load_balancer_table,
+             &northd_data->ls_datapaths, &northd_data->lbs);
+    engine_set_node_state(node, EN_UPDATED);
+}
+
+void
+en_sync_to_sb_lb_cleanup(void *data OVS_UNUSED)
+{
+
+}
+
+bool
+sync_to_sb_lb_northd_handler(struct engine_node *node, void *data OVS_UNUSED)
+{
+    struct northd_data *nd = engine_get_input_data("northd", node);
+    if (nd->change_tracked) {
+        /* There are only NB LSP related changes and these can be safely
+         * ignore and returned true.  However in case the northd engine
+         * tracking data includes other changes, we need to do additional
+         * checks before safely ignoring. */
+        return true;
+    }
+    return false;
+}
+
 /* static functions. */
 static void
 sync_addr_set(struct ovsdb_idl_txn *ovnsb_txn, const char *name,

northd/en-sync-sb.h

@@ -16,4 +16,10 @@ bool sync_to_sb_addr_set_nb_address_set_handler(struct engine_node *,
 bool sync_to_sb_addr_set_nb_port_group_handler(struct engine_node *,
                                                void *data);
 
+
+void *en_sync_to_sb_lb_init(struct engine_node *, struct engine_arg *);
+void en_sync_to_sb_lb_run(struct engine_node *, void *data);
+void en_sync_to_sb_lb_cleanup(void *data);
+bool sync_to_sb_lb_northd_handler(struct engine_node *, void *data OVS_UNUSED);
+
 #endif /* end of EN_SYNC_SB_H */

northd/inc-proc-northd.c

@@ -142,6 +142,7 @@ static ENGINE_NODE(sync_to_sb_addr_set, "sync_to_sb_addr_set");
 static ENGINE_NODE_WITH_CLEAR_TRACK_DATA(port_group, "port_group");
 static ENGINE_NODE(fdb_aging, "fdb_aging");
 static ENGINE_NODE(fdb_aging_waker, "fdb_aging_waker");
+static ENGINE_NODE(sync_to_sb_lb, "sync_to_sb_lb");
 
 void inc_proc_northd_init(struct ovsdb_idl_loop *nb,
                           struct ovsdb_idl_loop *sb)
@@ -165,7 +166,6 @@ void inc_proc_northd_init(struct ovsdb_idl_loop *nb,
     engine_add_input(&en_northd, &en_sb_ha_chassis_group, NULL);
     engine_add_input(&en_northd, &en_sb_ip_multicast, NULL);
     engine_add_input(&en_northd, &en_sb_service_monitor, NULL);
-    engine_add_input(&en_northd, &en_sb_load_balancer, NULL);
     engine_add_input(&en_northd, &en_sb_fdb, NULL);
     engine_add_input(&en_northd, &en_sb_static_mac_binding, NULL);
     engine_add_input(&en_northd, &en_sb_chassis_template_var, NULL);
@@ -216,14 +216,19 @@ void inc_proc_northd_init(struct ovsdb_idl_loop *nb,
      * table too (because of the explicit dependency in the schema). */
     engine_add_input(&en_port_group, &en_northd, engine_noop_handler);
 
+    engine_add_input(&en_sync_to_sb_lb, &en_northd,
+                     sync_to_sb_lb_northd_handler);
+    engine_add_input(&en_sync_to_sb_lb, &en_sb_load_balancer, NULL);
+
     /* en_sync_to_sb engine node syncs the SB database tables from
      * the NB database tables.
      * Right now this engine syncs the SB Address_Set table, Port_Group table
-     * and SB Meter/Meter_Band tables.
+     * SB Meter/Meter_Band tables and SB Load_Balancer table.
      */
     engine_add_input(&en_sync_to_sb, &en_sync_to_sb_addr_set, NULL);
     engine_add_input(&en_sync_to_sb, &en_port_group, NULL);
     engine_add_input(&en_sync_to_sb, &en_sync_meters, NULL);
+    engine_add_input(&en_sync_to_sb, &en_sync_to_sb_lb, NULL);
 
     engine_add_input(&en_sync_from_sb, &en_northd,
                      sync_from_sb_northd_handler);

northd/northd.c

@@ -4580,7 +4580,7 @@ ovn_dp_group_get_or_create(struct ovsdb_idl_txn *ovnsb_txn,
 /* Syncs relevant load balancers (applied to logical switches) to the
  * Southbound database.
  */
-static void
+void
 sync_lbs(struct ovsdb_idl_txn *ovnsb_txn,
          const struct sbrec_load_balancer_table *sbrec_load_balancer_table,
          struct ovn_datapaths *ls_datapaths, struct hmap *lbs)
@@ -17251,8 +17251,6 @@ ovnnb_db_run(struct northd_input *input_data,
     ovn_update_ipv6_options(&data->lr_ports);
     ovn_update_ipv6_prefix(&data->lr_ports);
 
-    sync_lbs(ovnsb_txn, input_data->sbrec_load_balancer_table,
-             &data->ls_datapaths, &data->lbs);
     sync_mirrors(ovnsb_txn, input_data->nbrec_mirror_table,
                  input_data->sbrec_mirror_table);
     sync_dns_entries(ovnsb_txn, input_data->sbrec_dns_table,

northd/northd.h

@@ -16,6 +16,7 @@
 
 #include "ovsdb-idl.h"
 
+#include "lib/ovn-sb-idl.h"
 #include "lib/ovn-util.h"
 #include "lib/ovs-atomic.h"
 #include "lib/sset.h"
@@ -45,7 +46,6 @@ struct northd_input {
     const struct sbrec_ha_chassis_group_table *sbrec_ha_chassis_group_table;
     const struct sbrec_chassis_table *sbrec_chassis_table;
     const struct sbrec_fdb_table *sbrec_fdb_table;
-    const struct sbrec_load_balancer_table *sbrec_load_balancer_table;
     const struct sbrec_service_monitor_table *sbrec_service_monitor_table;
     const struct sbrec_dns_table *sbrec_dns_table;
     const struct sbrec_ip_multicast_table *sbrec_ip_multicast_table;
@@ -350,4 +350,7 @@ const char *northd_get_svc_monitor_mac(void);
 
 const struct ovn_datapath *northd_get_datapath_for_port(
     const struct hmap *ls_ports, const char *port_name);
+void sync_lbs(struct ovsdb_idl_txn *, const struct sbrec_load_balancer_table *,
+              struct ovn_datapaths *ls_datapaths, struct hmap *lbs);
+
 #endif /* NORTHD_H */

tests/ovn-northd.at

@@ -9954,6 +9954,29 @@ AT_CHECK([ovn-sbctl lflow-list sw | grep ls_out_pre_lb | grep priority=110 | gre
 AT_CLEANUP
 ])
 
+
+# This test checks the compute/recompute stats of sync_to_sb_lb engine node
+OVN_FOR_EACH_NORTHD_NO_HV([
+AT_SETUP([sync_to_sb_lb incremental processing])
+ovn_start
+
+check ovn-nbctl ls-add sw
+check ovn-nbctl lsp-add sw p1
+
+check ovn-nbctl --wait=sb sync
+check as northd ovn-appctl -t NORTHD_TYPE inc-engine/clear-stats
+
+check ovn-nbctl --wait=sb lsp-set-options p1 foo=bar
+sb_lb_recomp=$(as northd ovn-appctl -t NORTHD_TYPE inc-engine/show-stats sync_to_sb_lb recompute)
+AT_CHECK([test x$sb_lb_recomp = x0])
+
+check ovn-nbctl --wait=sb lsp-set-type p1 external
+sb_lb_recomp=$(as northd ovn-appctl -t NORTHD_TYPE inc-engine/show-stats sync_to_sb_lb recompute)
+AT_CHECK([test x$sb_lb_recomp != x0])
+
+AT_CLEANUP
+])
+
 OVN_FOR_EACH_NORTHD_NO_HV([
 AT_SETUP([LSP incremental processing])
 ovn_start