cgroup: clean up cgroup_subsys names and initialization
cgroup_subsys is a bit messier than it needs to be.
* The name of a subsys can be different from its internal identifier
defined in cgroup_subsys.h. Most subsystems use the matching name
but three - cpu, memory and perf_event - use different ones.
* cgroup_subsys_id enums are postfixed with _subsys_id and each
cgroup_subsys is postfixed with _subsys. cgroup.h is widely
included throughout various subsystems, it doesn't and shouldn't
have claim on such generic names which don't have any qualifier
indicating that they belong to cgroup.
* cgroup_subsys->subsys_id should always equal the matching
cgroup_subsys_id enum; however, we require each controller to
initialize it and then BUG if they don't match, which is a bit
silly.
This patch cleans up cgroup_subsys names and initialization by doing
the followings.
* cgroup_subsys_id enums are now postfixed with _cgrp_id, and each
cgroup_subsys with _cgrp_subsys.
* With the above, renaming subsys identifiers to match the userland
visible names doesn't cause any naming conflicts. All non-matching
identifiers are renamed to match the official names.
cpu_cgroup -> cpu
mem_cgroup -> memory
perf -> perf_event
* controllers no longer need to initialize ->subsys_id and ->name.
They're generated in cgroup core and set automatically during boot.
* Redundant cgroup_subsys declarations removed.
* While updating BUG_ON()s in cgroup_init_early(), convert them to
WARN()s. BUGging that early during boot is stupid - the kernel
can't print anything, even through serial console and the trap
handler doesn't even link stack frame properly for back-tracing.
This patch doesn't introduce any behavior changes.
v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs
classid handling into core").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Ingo Molnar <mingo@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 53385cd..04a97bc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -66,8 +66,8 @@
#include <trace/events/vmscan.h>
-struct cgroup_subsys mem_cgroup_subsys __read_mostly;
-EXPORT_SYMBOL(mem_cgroup_subsys);
+struct cgroup_subsys memory_cgrp_subsys __read_mostly;
+EXPORT_SYMBOL(memory_cgrp_subsys);
#define MEM_CGROUP_RECLAIM_RETRIES 5
static struct mem_cgroup *root_mem_cgroup __read_mostly;
@@ -538,7 +538,7 @@
{
struct cgroup_subsys_state *css;
- css = css_from_id(id - 1, &mem_cgroup_subsys);
+ css = css_from_id(id - 1, &memory_cgrp_subsys);
return mem_cgroup_from_css(css);
}
@@ -1072,7 +1072,7 @@
if (unlikely(!p))
return NULL;
- return mem_cgroup_from_css(task_css(p, mem_cgroup_subsys_id));
+ return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
}
struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
@@ -1702,7 +1702,7 @@
rcu_read_lock();
mem_cgrp = memcg->css.cgroup;
- task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
+ task_cgrp = task_cgroup(p, memory_cgrp_id);
ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
if (ret < 0) {
@@ -6187,7 +6187,7 @@
ret = -EINVAL;
cfile_css = css_from_dir(cfile.file->f_dentry->d_parent,
- &mem_cgroup_subsys);
+ &memory_cgrp_subsys);
if (cfile_css == css && css_tryget(css))
ret = 0;
@@ -6566,11 +6566,11 @@
* unfortunate state in our controller.
*/
if (parent != root_mem_cgroup)
- mem_cgroup_subsys.broken_hierarchy = true;
+ memory_cgrp_subsys.broken_hierarchy = true;
}
mutex_unlock(&memcg_create_mutex);
- return memcg_init_kmem(memcg, &mem_cgroup_subsys);
+ return memcg_init_kmem(memcg, &memory_cgrp_subsys);
}
/*
@@ -7264,9 +7264,7 @@
mem_cgroup_from_css(root_css)->use_hierarchy = true;
}
-struct cgroup_subsys mem_cgroup_subsys = {
- .name = "memory",
- .subsys_id = mem_cgroup_subsys_id,
+struct cgroup_subsys memory_cgrp_subsys = {
.css_alloc = mem_cgroup_css_alloc,
.css_online = mem_cgroup_css_online,
.css_offline = mem_cgroup_css_offline,
@@ -7292,7 +7290,7 @@
static void __init memsw_file_init(void)
{
- WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, memsw_cgroup_files));
+ WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files));
}
static void __init enable_swap_cgroup(void)