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Date: Tue, 15 Sep 2015 21:51:24 -0400
From: Tejun Heo <tj@...nel.org>
To: lizefan@...wei.com, hannes@...xchg.org
Cc: cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
kernel-team@...com, Tejun Heo <tj@...nel.org>,
Michal Hocko <mhocko@...nel.org>
Subject: [PATCH 3/4] cgroup: replace cgroup_subsys->disabled tests with cgroup_subsys_enabled()
Replace cgroup_subsys->disabled tests in controllers with
cgroup_subsys_enabled(). cgroup_subsys_enabled() requires literal
subsys name as its parameter and thus can't be used for cgroup core
which iterates through controllers. For cgroup core, introduce and
use cgroup_ssid_enabled() which uses slower static_key_enabled() test
and can be indexed by subsys ID.
This leaves cgroup_subsys->disabled unused. Removed.
Signed-off-by: Tejun Heo <tj@...nel.org>
Cc: Li Zefan <lizefan@...wei.com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Michal Hocko <mhocko@...nel.org>
---
include/linux/cgroup-defs.h | 1 -
include/linux/hugetlb_cgroup.h | 4 +---
include/linux/memcontrol.h | 4 +---
kernel/cgroup.c | 28 +++++++++++++++++++++-------
4 files changed, 23 insertions(+), 14 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 4d8fcf2..c5d41c3 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -419,7 +419,6 @@ struct cgroup_subsys {
struct task_struct *task);
void (*bind)(struct cgroup_subsys_state *root_css);
- int disabled;
int early_init;
/*
diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
index bcc853e..7edd305 100644
--- a/include/linux/hugetlb_cgroup.h
+++ b/include/linux/hugetlb_cgroup.h
@@ -48,9 +48,7 @@ int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg)
static inline bool hugetlb_cgroup_disabled(void)
{
- if (hugetlb_cgrp_subsys.disabled)
- return true;
- return false;
+ return !cgroup_subsys_enabled(hugetlb_cgrp_subsys);
}
extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ad800e6..9aa7820 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -347,9 +347,7 @@ ino_t page_cgroup_ino(struct page *page);
static inline bool mem_cgroup_disabled(void)
{
- if (memory_cgrp_subsys.disabled)
- return true;
- return false;
+ return !cgroup_subsys_enabled(memory_cgrp_subsys);
}
/*
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3619389..5703ba7 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -224,6 +224,19 @@ static void kill_css(struct cgroup_subsys_state *css);
static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
bool is_add);
+/**
+ * cgroup_ssid_enabled - cgroup subsys enabled test by subsys ID
+ * @ssid: subsys ID of interest
+ *
+ * cgroup_subsys_enabled() can only be used with literal subsys names which
+ * is fine for individual subsystems but unsuitable for cgroup core. This
+ * is slower static_key_enabled() based test indexed by @ssid.
+ */
+static bool cgroup_ssid_enabled(int ssid)
+{
+ return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
+}
+
/* IDR wrappers which synchronize using cgroup_idr_lock */
static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
gfp_t gfp_mask)
@@ -1482,7 +1495,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
for_each_subsys(ss, i) {
if (strcmp(token, ss->legacy_name))
continue;
- if (ss->disabled)
+ if (!cgroup_ssid_enabled(i))
continue;
/* Mutually exclusive option 'all' + subsystem name */
@@ -1513,7 +1526,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
*/
if (all_ss || (!one_ss && !opts->none && !opts->name))
for_each_subsys(ss, i)
- if (!ss->disabled)
+ if (cgroup_ssid_enabled(i))
opts->subsys_mask |= (1 << i);
/*
@@ -2762,7 +2775,8 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
if (tok[0] == '\0')
continue;
for_each_subsys_which(ss, ssid, &tmp_ss_mask) {
- if (ss->disabled || strcmp(tok + 1, ss->name))
+ if (!cgroup_ssid_enabled(ssid) ||
+ strcmp(tok + 1, ss->name))
continue;
if (*tok == '+') {
@@ -3320,7 +3334,7 @@ static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
int ret;
- if (ss->disabled)
+ if (!cgroup_ssid_enabled(ss->id))
return 0;
if (!cfts || cfts[0].name[0] == '\0')
@@ -5082,7 +5096,7 @@ int __init cgroup_init(void)
* disabled flag and cftype registration needs kmalloc,
* both of which aren't available during early_init.
*/
- if (ss->disabled)
+ if (!cgroup_ssid_enabled(ssid))
continue;
cgrp_dfl_root.subsys_mask |= 1 << ss->id;
@@ -5217,7 +5231,8 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v)
for_each_subsys(ss, i)
seq_printf(m, "%s\t%d\t%d\t%d\n",
ss->legacy_name, ss->root->hierarchy_id,
- atomic_read(&ss->root->nr_cgrps), !ss->disabled);
+ atomic_read(&ss->root->nr_cgrps),
+ cgroup_ssid_enabled(i));
mutex_unlock(&cgroup_mutex);
return 0;
@@ -5508,7 +5523,6 @@ static int __init cgroup_disable(char *str)
continue;
static_branch_disable(cgroup_subsys_enabled_key[i]);
- ss->disabled = 1;
printk(KERN_INFO "Disabling %s control group subsystem\n",
ss->name);
break;
--
2.4.3
--
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