zfsonlinux/zfs — pull request #1450 by shenyan1 (2013-05-08 07:53:49+00:00)
Title: reduce unnecessary updates in metaslab tree.

This patch reduce unnecessary updates in metaslab_passivate. The function **metaslab_group_sort** only update the weight of metaslab.
But if the metaslab's weight <= size, zfs don't have to update the metagroup's metaslab_tree because its weight doesn't change.