On Wed, Jul 02, 2014 at 07:50:54PM -0400, Tejun Heo wrote: > Until now, cftype arrays carried files for both the default and legacy > hierarchies and the files which needed to be used on only one of them > were flagged with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE. This > gets confusing very quickly and we may end up exposing interface files > to the default hierarchy without thinking it through. > > This patch makes cgroup core provide separate sets of interfaces for > cftype handling so that the cftypes for the default and legacy > hierarchies are clearly distinguished. The previous two patches > renamed the existing ones so that they clearly indicate that they're > for the legacy hierarchies. This patch adds the interface for the > default hierarchy and apply them selectively depending on the > hierarchy type. > > * cftypes added through cgroup_subsys->dfl_cftypes and > cgroup_add_dfl_cftypes() only show up on the default hierarchy. > > * cftypes added through cgroup_subsys->legacy_cftypes and > cgroup_add_legacy_cftypes() only show up on the legacy hierarchies. > > * cgroup_subsys->dfl_cftypes and ->legacy_cftypes can point to the > same array for the cases where the interface files are identical on > both types of hierarchies. > > * This makes all the existing subsystem interface files legacy-only by > default and all subsystems will have no interface file created when > enabled on the default hierarchy. Each subsystem should explicitly > review and compose the interface for the default hierarchy. > > * A boot param "cgroup__DEVEL__legacy_files_on_dfl" is added which > makes subsystems which haven't decided the interface files for the > default hierarchy to present the legacy files on the default > hierarchy so that its behavior on the default hierarchy can be > tested. As the awkward name suggests, this is for development only. > > * memcg's CFTYPE_INSANE on "use_hierarchy" is noop now as the whole > array isn't used on the default hierarchy. The flag is removed. > > Signed-off-by: Tejun Heo <t...@kernel.org> > Cc: Johannes Weiner <han...@cmpxchg.org> > Cc: Michal Hocko <mho...@suse.cz> > Cc: Li Zefan <lize...@huawei.com> > Cc: Vivek Goyal <vgo...@redhat.com> > Cc: Peter Zijlstra <a.p.zijls...@chello.nl> > Cc: Paul Mackerras <pau...@samba.org> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: Arnaldo Carvalho de Melo <a...@kernel.org> > Cc: Aristeu Rozanski <a...@redhat.com> > Cc: Neil Horman <nhor...@tuxdriver.com> > Cc: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> Acked-by: Neil Horman <nhor...@tuxdriver.com>
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