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-rw-r--r--Documentation/cgroups/unified-hierarchy.txt80
-rw-r--r--include/linux/cgroup-defs.h5
-rw-r--r--include/linux/cgroup.h9
-rw-r--r--kernel/cgroup.c41
4 files changed, 111 insertions, 24 deletions
diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt
index 86847a7647ab..1ee9caf29e57 100644
--- a/Documentation/cgroups/unified-hierarchy.txt
+++ b/Documentation/cgroups/unified-hierarchy.txt
@@ -23,10 +23,13 @@ CONTENTS
5. Other Changes
5-1. [Un]populated Notification
5-2. Other Core Changes
- 5-3. Per-Controller Changes
- 5-3-1. blkio
- 5-3-2. cpuset
- 5-3-3. memory
+ 5-3. Controller File Conventions
+ 5-3-1. Format
+ 5-3-2. Control Knobs
+ 5-4. Per-Controller Changes
+ 5-4-1. blkio
+ 5-4-2. cpuset
+ 5-4-3. memory
6. Planned Changes
6-1. CAP for resource control
@@ -372,14 +375,75 @@ supported and the interface files "release_agent" and
- The "cgroup.clone_children" file is removed.
-5-3. Per-Controller Changes
+5-3. Controller File Conventions
-5-3-1. blkio
+5-3-1. Format
+
+In general, all controller files should be in one of the following
+formats whenever possible.
+
+- Values only files
+
+ VAL0 VAL1...\n
+
+- Flat keyed files
+
+ KEY0 VAL0\n
+ KEY1 VAL1\n
+ ...
+
+- Nested keyed files
+
+ KEY0 SUB_KEY0=VAL00 SUB_KEY1=VAL01...
+ KEY1 SUB_KEY0=VAL10 SUB_KEY1=VAL11...
+ ...
+
+For a writeable file, the format for writing should generally match
+reading; however, controllers may allow omitting later fields or
+implement restricted shortcuts for most common use cases.
+
+For both flat and nested keyed files, only the values for a single key
+can be written at a time. For nested keyed files, the sub key pairs
+may be specified in any order and not all pairs have to be specified.
+
+
+5-3-2. Control Knobs
+
+- Settings for a single feature should generally be implemented in a
+ single file.
+
+- In general, the root cgroup should be exempt from resource control
+ and thus shouldn't have resource control knobs.
+
+- If a controller implements ratio based resource distribution, the
+ control knob should be named "weight" and have the range [1, 10000]
+ and 100 should be the default value. The values are chosen to allow
+ enough and symmetric bias in both directions while keeping it
+ intuitive (the default is 100%).
+
+- If a controller implements an absolute resource guarantee and/or
+ limit, the control knobs should be named "min" and "max"
+ respectively. If a controller implements best effort resource
+ gurantee and/or limit, the control knobs should be named "low" and
+ "high" respectively.
+
+ In the above four control files, the special token "max" should be
+ used to represent upward infinity for both reading and writing.
+
+- If a setting has configurable default value and specific overrides,
+ the default settings should be keyed with "default" and appear as
+ the first entry in the file. Specific entries can use "default" as
+ its value to indicate inheritance of the default value.
+
+
+5-4. Per-Controller Changes
+
+5-4-1. blkio
- blk-throttle becomes properly hierarchical.
-5-3-2. cpuset
+5-4-2. cpuset
- Tasks are kept in empty cpusets after hotplug and take on the masks
of the nearest non-empty ancestor, instead of being moved to it.
@@ -388,7 +452,7 @@ supported and the interface files "release_agent" and
masks of the nearest non-empty ancestor.
-5-3-3. memory
+5-4-3. memory
- use_hierarchy is on by default and the cgroup file for the flag is
not created.
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 83e37d8c4d80..4d8fcf2187dc 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -323,7 +323,7 @@ struct cftype {
* end of cftype array.
*/
char name[MAX_CFTYPE_NAME];
- int private;
+ unsigned long private;
/*
* If not 0, file mode is set to this value, otherwise it will
* be figured out automatically
@@ -441,6 +441,9 @@ struct cgroup_subsys {
int id;
const char *name;
+ /* optional, initialized automatically during boot if not set */
+ const char *legacy_name;
+
/* link to parent, protected by cgroup_lock() */
struct cgroup_root *root;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index a71fe2a3984e..eb7ca55f72ef 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -22,6 +22,15 @@
#ifdef CONFIG_CGROUPS
+/*
+ * All weight knobs on the default hierarhcy should use the following min,
+ * default and max values. The default value is the logarithmic center of
+ * MIN and MAX and allows 100x to be expressed in both directions.
+ */
+#define CGROUP_WEIGHT_MIN 1
+#define CGROUP_WEIGHT_DFL 100
+#define CGROUP_WEIGHT_MAX 10000
+
/* a css_task_iter should be treated as an opaque object */
struct css_task_iter {
struct cgroup_subsys *ss;
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 97e2da0d3b27..4ec1b7ee5de8 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -145,6 +145,7 @@ static const char *cgroup_subsys_name[] = {
* part of that cgroup.
*/
struct cgroup_root cgrp_dfl_root;
+EXPORT_SYMBOL_GPL(cgrp_dfl_root);
/*
* The default hierarchy always exists but is hidden until mounted for the
@@ -1030,10 +1031,13 @@ static const struct file_operations proc_cgroupstats_operations;
static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
char *buf)
{
+ struct cgroup_subsys *ss = cft->ss;
+
if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
!(cgrp->root->flags & CGRP_ROOT_NOPREFIX))
snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",
- cft->ss->name, cft->name);
+ cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
+ cft->name);
else
strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
return buf;
@@ -1335,9 +1339,10 @@ static int cgroup_show_options(struct seq_file *seq,
struct cgroup_subsys *ss;
int ssid;
- for_each_subsys(ss, ssid)
- if (root->subsys_mask & (1 << ssid))
- seq_printf(seq, ",%s", ss->name);
+ if (root != &cgrp_dfl_root)
+ for_each_subsys(ss, ssid)
+ if (root->subsys_mask & (1 << ssid))
+ seq_printf(seq, ",%s", ss->legacy_name);
if (root->flags & CGRP_ROOT_NOPREFIX)
seq_puts(seq, ",noprefix");
if (root->flags & CGRP_ROOT_XATTR)
@@ -1450,7 +1455,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
}
for_each_subsys(ss, i) {
- if (strcmp(token, ss->name))
+ if (strcmp(token, ss->legacy_name))
continue;
if (ss->disabled)
continue;
@@ -4997,6 +5002,8 @@ int __init cgroup_init_early(void)
ss->id = i;
ss->name = cgroup_subsys_name[i];
+ if (!ss->legacy_name)
+ ss->legacy_name = cgroup_subsys_name[i];
if (ss->early_init)
cgroup_init_subsys(ss, true);
@@ -5140,9 +5147,11 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
continue;
seq_printf(m, "%d:", root->hierarchy_id);
- for_each_subsys(ss, ssid)
- if (root->subsys_mask & (1 << ssid))
- seq_printf(m, "%s%s", count++ ? "," : "", ss->name);
+ if (root != &cgrp_dfl_root)
+ for_each_subsys(ss, ssid)
+ if (root->subsys_mask & (1 << ssid))
+ seq_printf(m, "%s%s", count++ ? "," : "",
+ ss->legacy_name);
if (strlen(root->name))
seq_printf(m, "%sname=%s", count ? "," : "",
root->name);
@@ -5182,7 +5191,7 @@ 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->name, ss->root->hierarchy_id,
+ ss->legacy_name, ss->root->hierarchy_id,
atomic_read(&ss->root->nr_cgrps), !ss->disabled);
mutex_unlock(&cgroup_mutex);
@@ -5469,12 +5478,14 @@ static int __init cgroup_disable(char *str)
continue;
for_each_subsys(ss, i) {
- if (!strcmp(token, ss->name)) {
- ss->disabled = 1;
- printk(KERN_INFO "Disabling %s control group"
- " subsystem\n", ss->name);
- break;
- }
+ if (strcmp(token, ss->name) &&
+ strcmp(token, ss->legacy_name))
+ continue;
+
+ ss->disabled = 1;
+ printk(KERN_INFO "Disabling %s control group subsystem\n",
+ ss->name);
+ break;
}
}
return 1;