migration: export vcpu_dirty_limit_period

Define and export vcpu_dirty_limit_period to eliminate a dependency
on MigrationState.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Link: https://lore.kernel.org/r/1710179338-294359-6-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>

include/migration/client-options.h

@@ -20,5 +20,6 @@ bool migrate_switchover_ack(void);
 /* parameters */
 
 MigMode migrate_mode(void);
+uint64_t migrate_vcpu_dirty_limit_period(void);
 
 #endif

migration/options.c

@@ -924,6 +924,13 @@ const char *migrate_tls_hostname(void)
     return s->parameters.tls_hostname;
 }
 
+uint64_t migrate_vcpu_dirty_limit_period(void)
+{
+    MigrationState *s = migrate_get_current();
+
+    return s->parameters.x_vcpu_dirty_limit_period;
+}
+
 uint64_t migrate_xbzrle_cache_size(void)
 {
     MigrationState *s = migrate_get_current();

system/dirtylimit.c

@@ -77,14 +77,13 @@ static bool dirtylimit_quit;
 
 static void vcpu_dirty_rate_stat_collect(void)
 {
-    MigrationState *s = migrate_get_current();
     VcpuStat stat;
     int i = 0;
     int64_t period = DIRTYLIMIT_CALC_TIME_MS;
 
     if (migrate_dirty_limit() &&
         migration_is_active()) {
-        period = s->parameters.x_vcpu_dirty_limit_period;
+        period = migrate_vcpu_dirty_limit_period();
     }
 
     /* calculate vcpu dirtyrate */