Re: [PATCHSET cgroup/for-4.6] cgroup: update migration destination cgroup handling

From: Tejun Heo
Date: Tue Mar 08 2016 - 11:51:52 EST

On Thu, Mar 03, 2016 at 12:19:58PM -0500, Tejun Heo wrote:
> cgroup migrations used to always be single destination. There could
> be multiple sources but there was only one destination cgroup. This
> changed with default hierarchy as enabling a controller would move
> processes in child cgroups into separate csses. This was developed
> over time and is working correctly now but the way multiple
> destinations are handled is hacky and fragile. This patchset updates
> migration logic so that multi-destination handling is integral.
> This patchset contains the following four patches.
> 0001-cgroup-fix-incorrect-destination-cgroup-in-cgroup_up.patch
> 0002-cgroup-move-migration-destination-verification-out-o.patch
> 0003-cgroup-make-cgroup-_taskset-_migrate-take-cgroup_roo.patch
> 0004-cgroup-use-css_set-mg_dst_cgrp-for-the-migration-tar.patch

These changes are mostly mechanical and I want them to be in for-4.6
for a while before the merge window opens up. Applying to
cgroup/for-4.6. In the unlikely case that this breaks something,
let's fix with followup patches.