[ceph-users] rebalancing adapted during rebalancing with new updates?

When I add an osd rebalancing is taking place, lets say ceph relocates 40 pg's. When I add another osd during rebalancing, when ceph has only relocated 10 pgs and has to do still 30 pgs. What happens then: 1. Is ceph just finishing the relocation of these 30 pgs and then calculates how the new environment with the newly added osd should be relocated and starts relocating that. 2. or is ceph is finishing only the relocation of the pg it is currently doing, and then recalculates immediately how pg's should be distributed without finishing these 30 pg's it was planning to do.