migration: Create x-multifd-channels parameter

Indicates the number of channels that we will create.  By default we
create 2 channels.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

--

Catch inconsistent defaults (eric).
Improve comment stating that number of threads is the same than number
of sockets
Use new DEFIN_PROP_*
Rename x-multifd-threads to x-multifd-threads

2 files changed, 27 insertions, 0 deletions

diff --git a/migration/migration.c b/migration/migration.c
index 958b783bcf..7e79310d03 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -77,6 +77,7 @@
  * Note: Please change this default value to 10000 when we support hybrid mode.
  */
 #define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200
+#define DEFAULT_MIGRATE_MULTIFD_CHANNELS 2
 
 static NotifierList migration_state_notifiers =
     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
@@ -481,6 +482,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
     params->has_block_incremental = true;
     params->block_incremental = s->parameters.block_incremental;
+    params->has_x_multifd_channels = true;
+    params->x_multifd_channels = s->parameters.x_multifd_channels;
 
     return params;
 }
@@ -762,6 +765,13 @@ static bool migrate_params_check(MigrationParameters *params, Error **errp)
                     "is invalid, it should be positive");
         return false;
     }
+    if (params->has_x_multifd_channels &&
+        (params->x_multifd_channels < 1 || params->x_multifd_channels > 255)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "multifd_channels",
+                   "is invalid, it should be in the range of 1 to 255");
+        return false;
+    }
 
     return true;
 }
@@ -880,6 +890,9 @@ static void migrate_params_apply(MigrateSetParameters *params)
     if (params->has_block_incremental) {
         s->parameters.block_incremental = params->block_incremental;
     }
+    if (params->has_x_multifd_channels) {
+        s->parameters.x_multifd_channels = params->x_multifd_channels;
+    }
 }
 
 void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
@@ -1458,6 +1471,15 @@ bool migrate_use_multifd(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_X_MULTIFD];
 }
 
+int migrate_multifd_channels(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->parameters.x_multifd_channels;
+}
+
 int migrate_use_xbzrle(void)
 {
     MigrationState *s;
@@ -2223,6 +2245,9 @@ static Property migration_properties[] = {
     DEFINE_PROP_INT64("x-checkpoint-delay", MigrationState,
                       parameters.x_checkpoint_delay,
                       DEFAULT_MIGRATE_X_CHECKPOINT_DELAY),
+    DEFINE_PROP_INT64("x-multifd-channels", MigrationState,
+                      parameters.x_multifd_channels,
+                      DEFAULT_MIGRATE_MULTIFD_CHANNELS),
 
     /* Migration capabilities */
     DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
@@ -2280,6 +2305,7 @@ static void migration_instance_init(Object *obj)
     params->has_downtime_limit = true;
     params->has_x_checkpoint_delay = true;
     params->has_block_incremental = true;
+    params->has_x_multifd_channels = true;
 }
 
 /*
diff --git a/migration/migration.h b/migration/migration.h
index b7437f16ce..3060cbc374 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -175,6 +175,7 @@ bool migrate_zero_blocks(void);
 
 bool migrate_auto_converge(void);
 bool migrate_use_multifd(void);
+int migrate_multifd_channels(void);
 
 int migrate_use_xbzrle(void);
 int64_t migrate_xbzrle_cache_size(void);