diff options
| -rw-r--r-- | include/linux/cgroup.h | 21 | ||||
| -rw-r--r-- | kernel/cgroup.c | 27 |
2 files changed, 47 insertions, 1 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index eb7ca55f72ef..c3a9f1eb4097 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -17,6 +17,7 @@ #include <linux/fs.h> #include <linux/seq_file.h> #include <linux/kernfs.h> +#include <linux/jump_label.h> #include <linux/cgroup-defs.h> @@ -50,6 +51,26 @@ extern struct css_set init_css_set; #include <linux/cgroup_subsys.h> #undef SUBSYS +#define SUBSYS(_x) \ + extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ + extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; +#include <linux/cgroup_subsys.h> +#undef SUBSYS + +/** + * cgroup_subsys_enabled - fast test on whether a subsys is enabled + * @ss: subsystem in question + */ +#define cgroup_subsys_enabled(ss) \ + static_branch_likely(&ss ## _enabled_key) + +/** + * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy + * @ss: subsystem in question + */ +#define cgroup_subsys_on_dfl(ss) \ + static_branch_likely(&ss ## _on_dfl_key) + bool css_has_online_children(struct cgroup_subsys_state *css); struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 2cf0f79f1fc9..361938911bd1 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -139,6 +139,27 @@ static const char *cgroup_subsys_name[] = { }; #undef SUBSYS +/* array of static_keys for cgroup_subsys_enabled() and cgroup_subsys_on_dfl() */ +#define SUBSYS(_x) \ + DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_enabled_key); \ + DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_on_dfl_key); \ + EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_enabled_key); \ + EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_on_dfl_key); +#include <linux/cgroup_subsys.h> +#undef SUBSYS + +#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys_enabled_key, +static struct static_key_true *cgroup_subsys_enabled_key[] = { +#include <linux/cgroup_subsys.h> +}; +#undef SUBSYS + +#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys_on_dfl_key, +static struct static_key_true *cgroup_subsys_on_dfl_key[] = { +#include <linux/cgroup_subsys.h> +}; +#undef SUBSYS + /* * The default hierarchy, reserved for the subsystems that are otherwise * unattached - it never has more than a single cgroup, and all tasks are @@ -1319,9 +1340,12 @@ static int rebind_subsystems(struct cgroup_root *dst_root, /* default hierarchy doesn't enable controllers by default */ dst_root->subsys_mask |= 1 << ssid; - if (dst_root != &cgrp_dfl_root) { + if (dst_root == &cgrp_dfl_root) { + static_branch_enable(cgroup_subsys_on_dfl_key[ssid]); + } else { dst_root->cgrp.subtree_control |= 1 << ssid; cgroup_refresh_child_subsys_mask(&dst_root->cgrp); + static_branch_disable(cgroup_subsys_on_dfl_key[ssid]); } if (ss->bind) @@ -5483,6 +5507,7 @@ static int __init cgroup_disable(char *str) strcmp(token, ss->legacy_name)) continue; + static_branch_disable(cgroup_subsys_enabled_key[i]); ss->disabled = 1; printk(KERN_INFO "Disabling %s control group subsystem\n", ss->name); |