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| author | Tejun Heo <tj@kernel.org> | 2015-09-18 11:56:28 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2015-09-18 11:56:28 -0400 |
| commit | 49d1dc4b81797f88270832b11e9f73809e7e7209 (patch) | |
| tree | ff6548a57a57834e533a4404ddabf30139060ece /include/linux/cgroup.h | |
| parent | fa128fd735bd236b6b04d3fedfed7a784137c185 (diff) | |
| download | lwn-49d1dc4b81797f88270832b11e9f73809e7e7209.tar.gz lwn-49d1dc4b81797f88270832b11e9f73809e7e7209.zip | |
cgroup: implement static_key based cgroup_subsys_enabled() and cgroup_subsys_on_dfl()
Whether a subsys is enabled and attached to the default hierarchy
seldom changes and may be tested in the hot paths. This patch
implements static_key based cgroup_subsys_enabled() and
cgroup_subsys_on_dfl() tests.
The following patches will update the users and remove duplicate
mechanisms.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'include/linux/cgroup.h')
| -rw-r--r-- | include/linux/cgroup.h | 21 |
1 files changed, 21 insertions, 0 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, |