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authorTejun Heo <tj@kernel.org>2014-07-15 19:05:10 +0400
committerTejun Heo <tj@kernel.org>2014-07-15 19:05:10 +0400
commita8ddc8215e1a4cd9dc5d6210811cfc381a489ec2 (patch)
tree647056238f18f982969e1aad6d2f564e99d99d65 /include/linux/cgroup.h
parent2cf669a58dc08fa065a8bd0dca866c0e6cb358cc (diff)
downloadlinux-a8ddc8215e1a4cd9dc5d6210811cfc381a489ec2.tar.xz
cgroup: distinguish the default and legacy hierarchies when handling cftypes
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. v2: Updated documentation for cgroup__DEVEL__legacy_files_on_dfl. v3: Clear CFTYPE_ONLY_ON_DFL and CFTYPE_INSANE when cfts are removed as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Aristeu Rozanski <aris@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/cgroup.h')
-rw-r--r--include/linux/cgroup.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index f5f0feef2701..9f76236ac158 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -590,6 +590,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
+int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_rm_cftypes(struct cftype *cfts);
@@ -671,8 +672,12 @@ struct cgroup_subsys {
*/
struct list_head cfts;
- /* base cftypes, automatically registered with subsys itself */
- struct cftype *legacy_cftypes; /* used on the legacy hierarchies */
+ /*
+ * Base cftypes which are automatically registered. The two can
+ * point to the same array.
+ */
+ struct cftype *dfl_cftypes; /* for the default hierarchy */
+ struct cftype *legacy_cftypes; /* for the legacy hierarchies */
/*
* A subsystem may depend on other subsystems. When such subsystem