private long getLogFileSizeLimit() {
    if (rolling || mainLog) {
      return Long.MAX_VALUE;
    } else {
      long result = config.getLogFileSizeLimit();
      if (result == 0) {
        return Long.MAX_VALUE;
      }
      if (fileSizeLimitInKB) {
        // use KB instead of MB to speed up log rolling for test purpose
        return result * 1024;
      } else {
        return result * (1024 * 1024);
      }
    }
  }
Call when the config changes at runtime.
geode-core/src/main/java/org/apache/geode/internal/logging/ManagerLogWriter.java