From: Tejun Heo Date: Wed, 23 Apr 2014 15:13:16 +0000 (-0400) Subject: cgroup: prepare migration path for unified hierarchy X-Git-Tag: omap-for-v3.16/fixes-against-rc1~81^2~68 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f817de98513d060023be4fa1d061b29a6515273e;p=pandora-kernel.git cgroup: prepare migration path for unified hierarchy Unified hierarchy implementation would require re-migrating tasks onto the same cgroup on the default hierarchy to reflect updated effective csses. Update cgroup_migrate_prepare_dst() so that it accepts NULL as the destination cgrp. When NULL is specified, the destination is considered to be the cgroup on the default hierarchy associated with each css_set. After this change, the identity check in cgroup_migrate_add_src() isn't sufficient for noop detection as the associated csses may change without any cgroup association changing. The only way to tell whether a migration is noop or not is testing whether the source and destination csets are identical. The noop check in cgroup_migrate_add_src() is removed and cset identity test is added to cgroup_migreate_prepare_dst(). If it's detected that source and destination csets are identical, the cset is removed removed from @preloaded_csets and all the migration nodes are cleared which makes cgroup_migrate() ignore the cset. Also, make the function append the destination css_sets to @preloaded_list so that destination css_sets always come after source css_sets. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- Reading git-diff-tree failed