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Subject[PATCH 1/2] cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/
From 6e405c1ae4018d813e8ed9e0bd463d6976aebfa8 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Tue, 13 Nov 2012 12:21:50 -0800

clone_children is only meaningful for cpuset and will stay that way.
Rename the flag to reflect that and update documentation. Also, drop
clone_children() wrapper in cgroup.c. The thin wrapper is used only a
few times and one of them will go away soon.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Glauber Costa <glommer@parallels.com>
---
These two patches are based on top of "cgroup: allow->post_create() to
fail" patchset.

http://thread.gmane.org/gmane.linux.kernel.cgroups/5047
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-online-may-fail

and availalbe in the following branch.

git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-remove-post_clone

Thanks.

Documentation/cgroups/cgroups.txt | 8 +++-----
include/linux/cgroup.h | 6 ++++--
kernel/cgroup.c | 28 ++++++++++++----------------
3 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
index b06eea2..24cdf76 100644
--- a/Documentation/cgroups/cgroups.txt
+++ b/Documentation/cgroups/cgroups.txt
@@ -299,11 +299,9 @@ a cgroup hierarchy's release_agent path is empty.
1.5 What does clone_children do ?
---------------------------------

-If the clone_children flag is enabled (1) in a cgroup, then all
-cgroups created beneath will call the post_clone callbacks for each
-subsystem of the newly created cgroup. Usually when this callback is
-implemented for a subsystem, it copies the values of the parent
-subsystem, this is the case for the cpuset.
+This flag only affects the cpuset controller. If the clone_children
+flag is enabled (1) in a cgroup, a new cpuset cgroup will copy its
+configuration from the parent during initialization.

1.6 How do I use cgroups ?
--------------------------
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 89c631d..926d8d1 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -143,9 +143,11 @@ enum {
/* Control Group requires release notifications to userspace */
CGRP_NOTIFY_ON_RELEASE,
/*
- * Clone cgroup values when creating a new child cgroup
+ * Clone the parent's configuration when creating a new child
+ * cpuset cgroup. For historical reasons, this option can be
+ * specified at mount time and thus is implemented here.
*/
- CGRP_CLONE_CHILDREN,
+ CGRP_CPUSET_CLONE_CHILDREN,
};

struct cgroup {
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 46c5119..a49572e 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -296,11 +296,6 @@ static int notify_on_release(const struct cgroup *cgrp)
return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
}

-static int clone_children(const struct cgroup *cgrp)
-{
- return test_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
-}
-
/*
* for_each_subsys() allows you to iterate on each subsystem attached to
* an active hierarchy
@@ -1101,7 +1096,7 @@ static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
seq_puts(seq, ",xattr");
if (strlen(root->release_agent_path))
seq_printf(seq, ",release_agent=%s", root->release_agent_path);
- if (clone_children(&root->top_cgroup))
+ if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->top_cgroup.flags))
seq_puts(seq, ",clone_children");
if (strlen(root->name))
seq_printf(seq, ",name=%s", root->name);
@@ -1113,7 +1108,7 @@ struct cgroup_sb_opts {
unsigned long subsys_mask;
unsigned long flags;
char *release_agent;
- bool clone_children;
+ bool cpuset_clone_children;
char *name;
/* User explicitly requested empty subsystem */
bool none;
@@ -1164,7 +1159,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
continue;
}
if (!strcmp(token, "clone_children")) {
- opts->clone_children = true;
+ opts->cpuset_clone_children = true;
continue;
}
if (!strcmp(token, "xattr")) {
@@ -1474,8 +1469,8 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
strcpy(root->release_agent_path, opts->release_agent);
if (opts->name)
strcpy(root->name, opts->name);
- if (opts->clone_children)
- set_bit(CGRP_CLONE_CHILDREN, &root->top_cgroup.flags);
+ if (opts->cpuset_clone_children)
+ set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->top_cgroup.flags);
return root;
}

@@ -3905,7 +3900,7 @@ fail:
static u64 cgroup_clone_children_read(struct cgroup *cgrp,
struct cftype *cft)
{
- return clone_children(cgrp);
+ return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
}

static int cgroup_clone_children_write(struct cgroup *cgrp,
@@ -3913,9 +3908,9 @@ static int cgroup_clone_children_write(struct cgroup *cgrp,
u64 val)
{
if (val)
- set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+ set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
else
- clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+ clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
return 0;
}

@@ -4130,8 +4125,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);

- if (clone_children(parent))
- set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+ if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags))
+ set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);

for_each_subsys(root, ss) {
struct cgroup_subsys_state *css;
@@ -4148,7 +4143,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
goto err_free_all;
}
/* At error, ->css_free() callback has to free assigned ID. */
- if (clone_children(parent) && ss->post_clone)
+ if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags) &&
+ ss->post_clone)
ss->post_clone(cgrp);

if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&
--
1.7.11.7


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