block/mirror: Sleep periodically during bitmap scanning
Before, we only yield after initializing dirty bitmap, where the QMP
command would return. That may take very long, and guest IO will be
blocked.
Add sleep points like the later mirror iterations.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id:
1431486673-19280-1-git-send-email-famz@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>