MFC r353611: 10330 merge recent ZoL vdev and metaslab changes
illumos/illumos-gate@
a0b03b161c4df3cfc54fbc741db09b3bdc23ffba
https://github.com/illumos/illumos-gate/commit/
a0b03b161c4df3cfc54fbc741db09b3bdc23ffba
https://www.illumos.org/issues/10330
3 recent ZoL changes in the vdev and metaslab code which we can pull over:
PR 8324
c853f382db 8324 Change target size of metaslabs from 256GB to 16GB
PR 8290
b194fab0fb 8290 Factor metaslab_load_wait() in metaslab_load()
PR 8286
419ba59145 8286 Update vdev_is_spacemap_addressable() for new spacemap
encoding
Author: Serapheim Dimitropoulos <serapheimd@gmail.com>
Obtained from: illumos, ZoL
MFC after: 2 weeks