[Qemu-devel] [PATCH v5] migrate: Move max-bandwidth and downtime-limit to migrate_set_parameter

[Ashijeet Acharya <ashijeetacharya@gmail.com>]

Mark old-commands for speed and 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 update
the query part in both hmp and qmp qemu control interfaces.
NOTE: This patch is solely based on Eric's new boxed parameters from QAPI
patch series.

Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
---
Changes in v5:
- Include units in the output of 'info migrte_parameters'
- Change 'old-commands' to 'backwards' in deprecation comments
- Include a error check for overflow of downtime_limit value
- Solve long line issues
---
 hmp.c                         | 27 +++++++++++++++
 include/migration/migration.h |  1 -
 migration/migration.c         | 76 +++++++++++++++++++++++++++++++------------
 qapi-schema.json              | 23 +++++++++++--
 qmp-commands.hx               | 14 ++++++--
 5 files changed, 113 insertions(+), 28 deletions(-)

diff --git a/hmp.c b/hmp.c
index 0893b8e..f9c81b1 100644
--- a/hmp.c
+++ b/hmp.c
@@ -309,6 +309,14 @@ 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");
     }
 
@@ -1200,6 +1208,7 @@ 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");
@@ -1218,6 +1227,7 @@ 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");
@@ -1258,7 +1268,9 @@ 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;
@@ -1295,6 +1307,20 @@ 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) {
@@ -1310,6 +1336,7 @@ 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);
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 3c96623..a5429ee 100644
--- a/include/migration/migration.h
+++ b/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;
diff --git a/migration/migration.c b/migration/migration.c
index 42336e3..9b4aa55 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -44,6 +44,10 @@
 #define BUFFER_DELAY     100
 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
 
+/* Time in nanoseconds we are allowed to stop the source,
+ * for sending the last part */
+#define DEFAULT_MIGRATE_SET_DOWNTIME 300000000
+
 /* 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,
         },
     };
 
@@ -573,6 +578,10 @@ 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 / 1000000;
 
     return params;
 }
@@ -804,6 +813,20 @@ void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
                    "cpu_throttle_increment",
                    "an integer in the range of 1 to 99");
     }
+    if (params->has_max_bandwidth &&
+        (params->max_bandwidth < 0 || params->max_bandwidth > SIZE_MAX)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "max_bandwidth",
+                   "an integer in the range of 0 to 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;
@@ -828,6 +851,20 @@ 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) {
+        params->downtime_limit *= 1000000; /* convert to nanoseconds */
+
+        s = migrate_get_current();
+        max_downtime = params->downtime_limit;
+        s->parameters.downtime_limit = max_downtime;
+    }
 }
 
 
@@ -1159,30 +1196,27 @@ int64_t qmp_query_migrate_cache_size(Error **errp)
     return migrate_xbzrle_cache_size();
 }
 
-void qmp_migrate_set_speed(int64_t value, Error **errp)
+void qmp_migrate_set_speed(int64_t valuebw, Error **errp)
 {
-    MigrationState *s;
-
-    if (value < 0) {
-        value = 0;
-    }
-    if (value > SIZE_MAX) {
-        value = SIZE_MAX;
-    }
+    MigrationParameters p = {
+        .has_max_bandwidth = true,
+        .max_bandwidth = valuebw,
+    };
 
-    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)
+void qmp_migrate_set_downtime(double valuedowntime, Error **errp)
 {
-    value *= 1e9;
-    value = MAX(0, MIN(UINT64_MAX, value));
-    max_downtime = (uint64_t)value;
+    valuedowntime *= 1000; /* Convert to milliseconds */
+    valuedowntime = MAX(0, MIN(INT64_MAX, valuedowntime));
+
+    MigrationParameters p = {
+        .has_downtime_limit = true,
+        .downtime_limit = valuedowntime,
+    };
+
+    qmp_migrate_set_parameters(&p, errp);
 }
 
 bool migrate_postcopy_ram(void)
@@ -1854,7 +1888,7 @@ void migrate_fd_connect(MigrationState *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);
diff --git a/qapi-schema.json b/qapi-schema.json
index 88b4888..f92ec88 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -637,12 +637,19 @@
 #                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
@@ -691,6 +698,12 @@
 #                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',
@@ -700,7 +713,9 @@
             '*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
 #
@@ -1782,6 +1797,8 @@
 #
 # 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'} }
@@ -1795,7 +1812,7 @@
 #
 # 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
 ##
diff --git a/qmp-commands.hx b/qmp-commands.hx
index e6c9193..9c277dd 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3800,7 +3800,9 @@ 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:
@@ -3813,7 +3815,7 @@ EQMP
     {
         .name       = "migrate-set-parameters",
         .args_type  =
-            "compress-level:i?,compress-threads:i?,decompress-threads:i?,cpu-throttle-initial:i?,cpu-throttle-increment:i?",
+            "compress-level:i?,compress-threads:i?,decompress-threads:i?,cpu-throttle-initial:i?,cpu-throttle-increment:i?,max-bandwidth:i?,downtime-limit:i?",
         .mhandler.cmd_new = qmp_marshal_migrate_set_parameters,
     },
 SQMP
@@ -3830,6 +3832,10 @@ 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:
 
@@ -3842,7 +3848,9 @@ 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
       }
    }
 
-- 
2.6.2