migration: Run a post update routine after setting parameters

Some migration parameters are updated immediately once they are set
via migrate-set-parameters. Move that work outside of
migrate_params_apply() and leave that function with the single
responsibility of setting s->parameters and not doing any
side-effects.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20251215220041.12657-9-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>

diff --git a/migration/options.c b/migration/options.c
index b17347e43b23bd9e7e9cc2ef643e7ba38446f143..cb127e9c7225a09c00d01e4e43fa40f2ef62c98a 100644 (file)
--- a/migration/options.c
+++ b/migration/options.c
@@ -1125,6 +1125,31 @@ void migrate_params_init(MigrationParameters *params)
     params->has_cpr_exec_command = true;
 }
 
+static void migrate_post_update_params(MigrationParameters *new, Error **errp)
+{
+    MigrationState *s = migrate_get_current();
+
+    if (new->has_max_bandwidth) {
+        if (s->to_dst_file && !migration_in_postcopy()) {
+            migration_rate_set(new->max_bandwidth);
+        }
+    }
+
+    if (new->has_x_checkpoint_delay) {
+        colo_checkpoint_delay_set();
+    }
+
+    if (new->has_xbzrle_cache_size) {
+        xbzrle_cache_resize(new->xbzrle_cache_size, errp);
+    }
+
+    if (new->has_max_postcopy_bandwidth) {
+        if (s->to_dst_file && migration_in_postcopy()) {
+            migration_rate_set(new->max_postcopy_bandwidth);
+        }
+    }
+}
+
 /*
  * Check whether the parameters are valid. Error will be put into errp
  * (if provided). Return true if valid, otherwise false.
@@ -1439,7 +1464,7 @@ static void migrate_params_test_apply(MigrationParameters *params,
     }
 }
 
-static void migrate_params_apply(MigrationParameters *params, Error **errp)
+static void migrate_params_apply(MigrationParameters *params)
 {
     MigrationState *s = migrate_get_current();
 
@@ -1479,9 +1504,6 @@ static void migrate_params_apply(MigrationParameters *params, Error **errp)
 
     if (params->has_max_bandwidth) {
         s->parameters.max_bandwidth = params->max_bandwidth;
-        if (s->to_dst_file && !migration_in_postcopy()) {
-            migration_rate_set(s->parameters.max_bandwidth);
-        }
     }
 
     if (params->has_avail_switchover_bandwidth) {
@@ -1494,7 +1516,6 @@ static void migrate_params_apply(MigrationParameters *params, Error **errp)
 
     if (params->has_x_checkpoint_delay) {
         s->parameters.x_checkpoint_delay = params->x_checkpoint_delay;
-        colo_checkpoint_delay_set();
     }
 
     if (params->has_multifd_channels) {
@@ -1514,13 +1535,9 @@ static void migrate_params_apply(MigrationParameters *params, Error **errp)
     }
     if (params->has_xbzrle_cache_size) {
         s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
-        xbzrle_cache_resize(params->xbzrle_cache_size, errp);
     }
     if (params->has_max_postcopy_bandwidth) {
         s->parameters.max_postcopy_bandwidth = params->max_postcopy_bandwidth;
-        if (s->to_dst_file && migration_in_postcopy()) {
-            migration_rate_set(s->parameters.max_postcopy_bandwidth);
-        }
     }
     if (params->has_max_cpu_throttle) {
         s->parameters.max_cpu_throttle = params->max_cpu_throttle;
@@ -1594,7 +1611,8 @@ void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
     migrate_params_test_apply(params, &tmp);
 
     if (migrate_params_check(&tmp, errp)) {
-        migrate_params_apply(params, errp);
+        migrate_params_apply(params);
+        migrate_post_update_params(params, errp);
     }
 
     migrate_tls_opts_free(&tmp);

diff --git a/migration/ram.c b/migration/ram.c
index ecd81601e26ece8b83c79b3d3f7066467e90fd4f..18e4e26eaf826b8792edd70012ea3fad91358979 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -176,7 +176,7 @@ static void XBZRLE_cache_unlock(void)
 /**
  * xbzrle_cache_resize: resize the xbzrle cache
  *
- * This function is called from migrate_params_apply in main
+ * This function is called from migrate_post_update_params in main
  * thread, possibly while a migration is in progress.  A running
  * migration may be using the cache and might finish during this call,
  * hence changes to the cache are protected by XBZRLE.lock().