code: func (daemon *Daemon) mergeUlimits(c *containertypes.HostConfig) {
  	ulimits := c.Ulimits
  	// Merge ulimits with daemon defaults
  	ulIdx := make(map[string]struct{})
  	for _, ul := range ulimits {
  		ulIdx[ul.Name] = struct{}{}
  	}
  	for name, ul := range daemon.configStore.Ulimits {
  		if _, exists := ulIdx[name]; !exists {
  			ulimits = append(ulimits, ul)
  		}
  	}
  	c.Ulimits = ulimits
  }
docs: // mergeUlimits merge the Ulimits from HostConfig with daemon defaults, and update HostConfig