diff options
| -rw-r--r-- | Documentation/cgroups/unified-hierarchy.txt | 18 | ||||
| -rw-r--r-- | include/linux/cgroup.h | 9 | ||||
| -rw-r--r-- | kernel/cgroup.c | 62 | ||||
| -rw-r--r-- | mm/memcontrol.c | 1 |
4 files changed, 78 insertions, 12 deletions
diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index a7a2205..4f45632 100644 --- a/Documentation/cgroups/unified-hierarchy.txt +++ b/Documentation/cgroups/unified-hierarchy.txt @@ -94,12 +94,18 @@ change soon. mount -t cgroup -o __DEVEL__sane_behavior cgroup $MOUNT_POINT -All controllers which are not bound to other hierarchies are -automatically bound to unified hierarchy and show up at the root of -it. Controllers which are enabled only in the root of unified -hierarchy can be bound to other hierarchies. This allows mixing -unified hierarchy with the traditional multiple hierarchies in a fully -backward compatible way. +All controllers which support the unified hierarchy and are not bound +to other hierarchies are automatically bound to unified hierarchy and +show up at the root of it. Controllers which are enabled only in the +root of unified hierarchy can be bound to other hierarchies. This +allows mixing unified hierarchy with the traditional multiple +hierarchies in a fully backward compatible way. + +For development purposes, the following boot parameter makes all +controllers to appear on the unified hierarchy whether supported or +not. + + cgroup__DEVEL__legacy_files_on_dfl A controller can be moved across hierarchies only after the controller is no longer referenced in its current hierarchy. Because per-cgroup diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index f5f0fee..9f76236 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 diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c275aa4..374ebdf 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -149,6 +149,12 @@ struct cgroup_root cgrp_dfl_root; */ static bool cgrp_dfl_root_visible; +/* + * Set by the boot param of the same name and makes subsystems with NULL + * ->dfl_files to use ->legacy_files on the default hierarchy. + */ +static bool cgroup_legacy_files_on_dfl; + /* some controllers are not supported in the default hierarchy */ static const unsigned int cgrp_dfl_root_inhibit_ss_mask = 0 #ifdef CONFIG_CGROUP_DEBUG @@ -3085,6 +3091,9 @@ static void cgroup_exit_cftypes(struct cftype *cfts) kfree(cft->kf_ops); cft->kf_ops = NULL; cft->ss = NULL; + + /* revert flags set by cgroup core while adding @cfts */ + cft->flags &= ~(CFTYPE_ONLY_ON_DFL | CFTYPE_INSANE); } } @@ -3195,8 +3204,37 @@ static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) return ret; } +/** + * cgroup_add_dfl_cftypes - add an array of cftypes for default hierarchy + * @ss: target cgroup subsystem + * @cfts: zero-length name terminated array of cftypes + * + * Similar to cgroup_add_cftypes() but the added files are only used for + * the default hierarchy. + */ +int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) +{ + struct cftype *cft; + + for (cft = cfts; cft && cft->name[0] != '\0'; cft++) + cft->flags |= CFTYPE_ONLY_ON_DFL; + return cgroup_add_cftypes(ss, cfts); +} + +/** + * cgroup_add_legacy_cftypes - add an array of cftypes for legacy hierarchies + * @ss: target cgroup subsystem + * @cfts: zero-length name terminated array of cftypes + * + * Similar to cgroup_add_cftypes() but the added files are only used for + * the legacy hierarchies. + */ int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) { + struct cftype *cft; + + for (cft = cfts; cft && cft->name[0] != '\0'; cft++) + cft->flags |= CFTYPE_INSANE; return cgroup_add_cftypes(ss, cfts); } @@ -4893,9 +4931,19 @@ int __init cgroup_init(void) * disabled flag and cftype registration needs kmalloc, * both of which aren't available during early_init. */ - if (!ss->disabled) { - cgrp_dfl_root.subsys_mask |= 1 << ss->id; - WARN_ON(cgroup_add_cftypes(ss, ss->legacy_cftypes)); + if (ss->disabled) + continue; + + cgrp_dfl_root.subsys_mask |= 1 << ss->id; + + if (cgroup_legacy_files_on_dfl && !ss->dfl_cftypes) + ss->dfl_cftypes = ss->legacy_cftypes; + + if (ss->dfl_cftypes == ss->legacy_cftypes) { + WARN_ON(cgroup_add_cftypes(ss, ss->dfl_cftypes)); + } else { + WARN_ON(cgroup_add_dfl_cftypes(ss, ss->dfl_cftypes)); + WARN_ON(cgroup_add_legacy_cftypes(ss, ss->legacy_cftypes)); } } @@ -5291,6 +5339,14 @@ static int __init cgroup_disable(char *str) } __setup("cgroup_disable=", cgroup_disable); +static int __init cgroup_set_legacy_files_on_dfl(char *str) +{ + printk("cgroup: using legacy files on the default hierarchy\n"); + cgroup_legacy_files_on_dfl = true; + return 0; +} +__setup("cgroup__DEVEL__legacy_files_on_dfl", cgroup_set_legacy_files_on_dfl); + /** * css_tryget_online_from_dir - get corresponding css from a cgroup dentry * @dentry: directory dentry of interest diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b6b3c6f..45c10c6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6003,7 +6003,6 @@ static struct cftype mem_cgroup_files[] = { }, { .name = "use_hierarchy", - .flags = CFTYPE_INSANE, .write_u64 = mem_cgroup_hierarchy_write, .read_u64 = mem_cgroup_hierarchy_read, }, |