[PULL,10/18] COLO: Add checkpoint-delay parameter for migrate-set-parameters

diff --git a/docs/qmp-commands.txt b/docs/qmp-commands.txt
index 9bdbbfe..2e42929 100644
--- a/docs/qmp-commands.txt
+++ b/docs/qmp-commands.txt
@@ -2916,6 +2916,8 @@  Set migration parameters
 - "max-bandwidth": set maximum speed for migrations (in bytes/sec) (json-int)
 - "downtime-limit": set maximum tolerated downtime (in milliseconds) for
                     migrations (json-int)
+- "x-checkpoint-delay": set the delay time for periodic checkpoint (json-int)
+
 Arguments:
 
 Example:
diff --git a/hmp.c b/hmp.c
index 3d60259..f2b831a 100644
--- a/hmp.c
+++ b/hmp.c
@@ -318,6 +318,9 @@  void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, " %s: %" PRId64 " milliseconds",
             MigrationParameter_lookup[MIGRATION_PARAMETER_DOWNTIME_LIMIT],
             params->downtime_limit);
+        monitor_printf(mon, " %s: %" PRId64,
+            MigrationParameter_lookup[MIGRATION_PARAMETER_X_CHECKPOINT_DELAY],
+            params->x_checkpoint_delay);
         monitor_printf(mon, "\n");
     }
 
@@ -1386,6 +1389,10 @@  void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
                 p.has_downtime_limit = true;
                 use_int_value = true;
                 break;
+            case MIGRATION_PARAMETER_X_CHECKPOINT_DELAY:
+                p.has_x_checkpoint_delay = true;
+                use_int_value = true;
+                break;
             }
 
             if (use_int_value) {
@@ -1402,6 +1409,7 @@  void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
                 p.cpu_throttle_initial = valueint;
                 p.cpu_throttle_increment = valueint;
                 p.downtime_limit = valueint;
+                p.x_checkpoint_delay = valueint;
             }
 
             qmp_migrate_set_parameters(&p, &err);
diff --git a/migration/migration.c b/migration/migration.c
index d8421b5..d87065a 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -63,6 +63,11 @@ 
 /* Migration XBZRLE default cache size */
 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
 
+/* The delay time (in ms) between two COLO checkpoints
+ * Note: Please change this default value to 10000 when we support hybrid mode.
+ */
+#define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200
+
 static NotifierList migration_state_notifiers =
     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
 
@@ -95,6 +100,7 @@  MigrationState *migrate_get_current(void)
             .cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT,
             .max_bandwidth = MAX_THROTTLE,
             .downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME,
+            .x_checkpoint_delay = DEFAULT_MIGRATE_X_CHECKPOINT_DELAY,
         },
     };
 
@@ -587,6 +593,7 @@  MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     params->max_bandwidth = s->parameters.max_bandwidth;
     params->has_downtime_limit = true;
     params->downtime_limit = s->parameters.downtime_limit;
+    params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
 
     return params;
 }
@@ -845,6 +852,11 @@  void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
                    "an integer in the range of 0 to 2000000 milliseconds");
         return;
     }
+    if (params->has_x_checkpoint_delay && (params->x_checkpoint_delay < 0)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                    "x_checkpoint_delay",
+                    "is invalid, it should be positive");
+    }
 
     if (params->has_compress_level) {
         s->parameters.compress_level = params->compress_level;
@@ -879,6 +891,10 @@  void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
     if (params->has_downtime_limit) {
         s->parameters.downtime_limit = params->downtime_limit;
     }
+
+    if (params->has_x_checkpoint_delay) {
+        s->parameters.x_checkpoint_delay = params->x_checkpoint_delay;
+    }
 }
 
 
diff --git a/qapi-schema.json b/qapi-schema.json
index ee58fe6..05fed9a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -674,19 +674,24 @@ 
 # @downtime-limit: set maximum tolerated downtime for migration. maximum
 #                  downtime in milliseconds (Since 2.8)
 #
+# @x-checkpoint-delay: The delay time (in ms) between two COLO checkpoints in
+#          periodic mode. (Since 2.8)
+#
 # Since: 2.4
 ##
 { 'enum': 'MigrationParameter',
   'data': ['compress-level', 'compress-threads', 'decompress-threads',
            'cpu-throttle-initial', 'cpu-throttle-increment',
            'tls-creds', 'tls-hostname', 'max-bandwidth',
-           'downtime-limit'] }
+           'downtime-limit', 'x-checkpoint-delay' ] }
 
 #
 # @migrate-set-parameters
 #
 # Set various migration parameters.  See MigrationParameters for details.
 #
+# @x-checkpoint-delay: the delay time between two checkpoints. (Since 2.8)
+#
 # Since: 2.4
 ##
 { 'command': 'migrate-set-parameters', 'boxed': true,
@@ -735,6 +740,8 @@ 
 # @downtime-limit: set maximum tolerated downtime for migration. maximum
 #                  downtime in milliseconds (Since 2.8)
 #
+# @x-checkpoint-delay: the delay time between two COLO checkpoints. (Since 2.8)
+#
 # Since: 2.4
 ##
 { 'struct': 'MigrationParameters',
@@ -746,7 +753,8 @@ 
             '*tls-creds': 'str',
             '*tls-hostname': 'str',
             '*max-bandwidth': 'int',
-            '*downtime-limit': 'int'} }
+            '*downtime-limit': 'int',
+            '*x-checkpoint-delay': 'int'} }
 
 ##
 # @query-migrate-parameters