migrate: move max-bandwidth and downtime-limit to migrate_set_parameter

Mark the old commands 'migrate_set_speed' and 'migrate_set_downtime' as
deprecated.
Move max-bandwidth and downtime-limit into migrate-set-parameters for
setting maximum migration speed and expected downtime limit parameters
respectively.
Change downtime units to milliseconds (only for new-command) and set
its upper bound limit to 2000 seconds.
Update the query part in both hmp and qmp qemu control interfaces.

Signed-off-by: Ashijeet Acharya <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Reviewed-by: Juan Quintela <[email protected]>
Signed-off-by: Juan Quintela <[email protected]>

Author: ashijeet24

docs/qmp-commands.txt

@@ -2910,7 +2910,9 @@ Set migration parameters
                           throttled for auto-converge (json-int)
 - "cpu-throttle-increment": set throttle increasing percentage for
                             auto-converge (json-int)
-
+- "max-bandwidth": set maximum speed for migrations (in bytes/sec) (json-int)
+- "downtime-limit": set maximum tolerated downtime (in milliseconds) for
+                    migrations (json-int)
 Arguments:
 
 Example:
@@ -2931,7 +2933,10 @@ Query current migration parameters
                                     throttled (json-int)
          - "cpu-throttle-increment" : throttle increasing percentage for
                                       auto-converge (json-int)
-
+         - "max-bandwidth" : maximium migration speed in bytes per second
+                             (json-int)
+         - "downtime-limit" : maximum tolerated downtime of migration in
+                              milliseconds (json-int)
 Arguments:
 
 Example:
@@ -2943,7 +2948,9 @@ Example:
          "cpu-throttle-increment": 10,
          "compress-threads": 8,
          "compress-level": 1,
-         "cpu-throttle-initial": 20
+         "cpu-throttle-initial": 20,
+         "max-bandwidth": 33554432,
+         "downtime-limit": 300
       }
    }
 

hmp.c

@@ -310,6 +310,14 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, " %s: '%s'",
             MigrationParameter_lookup[MIGRATION_PARAMETER_TLS_HOSTNAME],
             params->has_tls_hostname ? params->tls_hostname : "");
+        assert(params->has_max_bandwidth);
+        monitor_printf(mon, " %s: %" PRId64 " bytes/second",
+            MigrationParameter_lookup[MIGRATION_PARAMETER_MAX_BANDWIDTH],
+            params->max_bandwidth);
+        assert(params->has_downtime_limit);
+        monitor_printf(mon, " %s: %" PRId64 " milliseconds",
+            MigrationParameter_lookup[MIGRATION_PARAMETER_DOWNTIME_LIMIT],
+            params->downtime_limit);
         monitor_printf(mon, "\n");
     }
 
@@ -1265,6 +1273,7 @@ void hmp_migrate_incoming(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, &err);
 }
 
+/* Kept for backwards compatibility */
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 {
     double value = qdict_get_double(qdict, "value");
@@ -1283,6 +1292,7 @@ void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict)
     }
 }
 
+/* Kept for backwards compatibility */
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict)
 {
     int64_t value = qdict_get_int(qdict, "value");
@@ -1323,7 +1333,9 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
 {
     const char *param = qdict_get_str(qdict, "parameter");
     const char *valuestr = qdict_get_str(qdict, "value");
+    int64_t valuebw = 0;
     long valueint = 0;
+    char *endp;
     Error *err = NULL;
     bool use_int_value = false;
     int i;
@@ -1360,6 +1372,20 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
                 p.has_tls_hostname = true;
                 p.tls_hostname = (char *) valuestr;
                 break;
+            case MIGRATION_PARAMETER_MAX_BANDWIDTH:
+                p.has_max_bandwidth = true;
+                valuebw = qemu_strtosz(valuestr, &endp);
+                if (valuebw < 0 || (size_t)valuebw != valuebw
+                    || *endp != '\0') {
+                    error_setg(&err, "Invalid size %s", valuestr);
+                    goto cleanup;
+                }
+                p.max_bandwidth = valuebw;
+                break;
+            case MIGRATION_PARAMETER_DOWNTIME_LIMIT:
+                p.has_downtime_limit = true;
+                use_int_value = true;
+                break;
             }
 
             if (use_int_value) {
@@ -1375,6 +1401,7 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
                 p.decompress_threads = valueint;
                 p.cpu_throttle_initial = valueint;
                 p.cpu_throttle_increment = valueint;
+                p.downtime_limit = valueint;
             }
 
             qmp_migrate_set_parameters(&p, &err);

include/migration/migration.h

@@ -129,7 +129,6 @@ struct MigrationSrcPageRequest {
 
 struct MigrationState
 {
-    int64_t bandwidth_limit;
     size_t bytes_xfer;
     size_t xfer_limit;
     QemuThread thread;

migration/migration.c

@@ -44,6 +44,10 @@
 #define BUFFER_DELAY     100
 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
 
+/* Time in milliseconds we are allowed to stop the source,
+ * for sending the last part */
+#define DEFAULT_MIGRATE_SET_DOWNTIME 300
+
 /* Default compression thread count */
 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
 /* Default decompression thread count, usually decompression is at
@@ -80,7 +84,6 @@ MigrationState *migrate_get_current(void)
     static bool once;
     static MigrationState current_migration = {
         .state = MIGRATION_STATUS_NONE,
-        .bandwidth_limit = MAX_THROTTLE,
         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
         .mbps = -1,
         .parameters = {
@@ -89,6 +92,8 @@ MigrationState *migrate_get_current(void)
             .decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
             .cpu_throttle_initial = DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL,
             .cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT,
+            .max_bandwidth = MAX_THROTTLE,
+            .downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME,
         },
     };
 
@@ -517,17 +522,6 @@ void migrate_send_rp_pong(MigrationIncomingState *mis,
     migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
 }
 
-/* amount of nanoseconds we are willing to wait for migration to be down.
- * the choice of nanoseconds is because it is the maximum resolution that
- * get_clock() can achieve. It is an internal measure. All user-visible
- * units must be in seconds */
-static uint64_t max_downtime = 300000000;
-
-uint64_t migrate_max_downtime(void)
-{
-    return max_downtime;
-}
-
 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
 {
     MigrationCapabilityStatusList *head = NULL;
@@ -573,6 +567,10 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     params->tls_creds = g_strdup(s->parameters.tls_creds);
     params->has_tls_hostname = !!s->parameters.tls_hostname;
     params->tls_hostname = g_strdup(s->parameters.tls_hostname);
+    params->has_max_bandwidth = true;
+    params->max_bandwidth = s->parameters.max_bandwidth;
+    params->has_downtime_limit = true;
+    params->downtime_limit = s->parameters.downtime_limit;
 
     return params;
 }
@@ -806,6 +804,19 @@ void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
                    "an integer in the range of 1 to 99");
         return;
     }
+    if (params->has_max_bandwidth &&
+        (params->max_bandwidth < 0 || params->max_bandwidth > SIZE_MAX)) {
+        error_setg(errp, "Parameter 'max_bandwidth' expects an integer in the"
+                         " range of 0 to %zu bytes/second", SIZE_MAX);
+        return;
+    }
+    if (params->has_downtime_limit &&
+        (params->downtime_limit < 0 || params->downtime_limit > 2000000)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "downtime_limit",
+                   "an integer in the range of 0 to 2000000 milliseconds");
+        return;
+    }
 
     if (params->has_compress_level) {
         s->parameters.compress_level = params->compress_level;
@@ -830,6 +841,16 @@ void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
         g_free(s->parameters.tls_hostname);
         s->parameters.tls_hostname = g_strdup(params->tls_hostname);
     }
+    if (params->has_max_bandwidth) {
+        s->parameters.max_bandwidth = params->max_bandwidth;
+        if (s->to_dst_file) {
+            qemu_file_set_rate_limit(s->to_dst_file,
+                                s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
+        }
+    }
+    if (params->has_downtime_limit) {
+        s->parameters.downtime_limit = params->downtime_limit;
+    }
 }
 
 
@@ -1163,28 +1184,25 @@ int64_t qmp_query_migrate_cache_size(Error **errp)
 
 void qmp_migrate_set_speed(int64_t value, Error **errp)
 {
-    MigrationState *s;
-
-    if (value < 0) {
-        value = 0;
-    }
-    if (value > SIZE_MAX) {
-        value = SIZE_MAX;
-    }
+    MigrationParameters p = {
+        .has_max_bandwidth = true,
+        .max_bandwidth = value,
+    };
 
-    s = migrate_get_current();
-    s->bandwidth_limit = value;
-    if (s->to_dst_file) {
-        qemu_file_set_rate_limit(s->to_dst_file,
-                                 s->bandwidth_limit / XFER_LIMIT_RATIO);
-    }
+    qmp_migrate_set_parameters(&p, errp);
 }
 
 void qmp_migrate_set_downtime(double value, Error **errp)
 {
-    value *= 1e9;
-    value = MAX(0, MIN(UINT64_MAX, value));
-    max_downtime = (uint64_t)value;
+    value *= 1000; /* Convert to milliseconds */
+    value = MAX(0, MIN(INT64_MAX, value));
+
+    MigrationParameters p = {
+        .has_downtime_limit = true,
+        .downtime_limit = value,
+    };
+
+    qmp_migrate_set_parameters(&p, errp);
 }
 
 bool migrate_postcopy_ram(void)
@@ -1791,7 +1809,7 @@ static void *migration_thread(void *opaque)
                                          initial_bytes;
             uint64_t time_spent = current_time - initial_time;
             double bandwidth = (double)transferred_bytes / time_spent;
-            max_size = bandwidth * migrate_max_downtime() / 1000000;
+            max_size = bandwidth * s->parameters.downtime_limit;
 
             s->mbps = (((double) transferred_bytes * 8.0) /
                     ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
@@ -1850,13 +1868,12 @@ static void *migration_thread(void *opaque)
 
 void migrate_fd_connect(MigrationState *s)
 {
-    /* This is a best 1st approximation. ns to ms */
-    s->expected_downtime = max_downtime/1000000;
+    s->expected_downtime = s->parameters.downtime_limit;
     s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
 
     qemu_file_set_blocking(s->to_dst_file, true);
     qemu_file_set_rate_limit(s->to_dst_file,
-                             s->bandwidth_limit / XFER_LIMIT_RATIO);
+                             s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
 
     /* Notify before starting migration thread */
     notifier_list_notify(&migration_state_notifiers, s);

qapi-schema.json

@@ -658,12 +658,19 @@
 #                hostname must be provided so that the server's x509
 #                certificate identity can be validated. (Since 2.7)
 #
+# @max-bandwidth: to set maximum speed for migration. maximum speed in
+#                 bytes per second. (Since 2.8)
+#
+# @downtime-limit: set maximum tolerated downtime for migration. maximum
+#                  downtime in milliseconds (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'] }
+           'tls-creds', 'tls-hostname', 'max-bandwidth',
+           'downtime-limit'] }
 
 #
 # @migrate-set-parameters
@@ -712,6 +719,12 @@
 #                hostname must be provided so that the server's x509
 #                certificate identity can be validated. (Since 2.7)
 #
+# @max-bandwidth: to set maximum speed for migration. maximum speed in
+#                 bytes per second. (Since 2.8)
+#
+# @downtime-limit: set maximum tolerated downtime for migration. maximum
+#                  downtime in milliseconds (Since 2.8)
+#
 # Since: 2.4
 ##
 { 'struct': 'MigrationParameters',
@@ -721,7 +734,9 @@
             '*cpu-throttle-initial': 'int',
             '*cpu-throttle-increment': 'int',
             '*tls-creds': 'str',
-            '*tls-hostname': 'str'} }
+            '*tls-hostname': 'str',
+            '*max-bandwidth': 'int',
+            '*downtime-limit': 'int'} }
 ##
 # @query-migrate-parameters
 #
@@ -1803,6 +1818,8 @@
 #
 # Returns: nothing on success
 #
+# Notes: This command is deprecated in favor of 'migrate-set-parameters'
+#
 # Since: 0.14.0
 ##
 { 'command': 'migrate_set_downtime', 'data': {'value': 'number'} }
@@ -1816,7 +1833,7 @@
 #
 # Returns: nothing on success
 #
-# Notes: A value lesser than zero will be automatically round up to zero.
+# Notes: This command is deprecated in favor of 'migrate-set-parameters'
 #
 # Since: 0.14.0
 ##