Using innodb buffer pool dump:
innodb_buffer_pool_dump_at_shutdown=1
innodb_buffer_pool_load_at_startup=1
Does not work with 10.1. To reproduce:
Set the two variables above
Create an innodb table with a few Gb of data and read it.
Watch Innodb_buffer_pool_pages_data and the InnoDB ib_buffer_pool dump file
Shutdown down the server and restart it. Following the restart you see that the ib_buffer_pool file has shrunk and that there is much less data in Innodb_buffer_pool_pages_data than what it should be.

See https://bugs.launchpad.net/percona-xtradb-cluster/+bug/1305955 for a probably bug causing this (innodb restart while wsrep patch initializes cause this behavior).