On Mon, Sep 27, 2010 at 3:14 AM, Daniel Lezcano <daniel.lezcano@xxxxxxx> wrote:
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxx>
> Signed-off-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> Cc: Paul Menage <menage@xxxxxxxxxx>
> Reviewed-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Acked-by: Paul Menage <menage@xxxxxxxxxx>
> ---
> Documentation/cgroups/cgroups.txt | 14 +++++++++++-
> include/linux/cgroup.h | 4 +++
> kernel/cgroup.c | 39 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
> index b34823f..190018b 100644
> --- a/Documentation/cgroups/cgroups.txt
> +++ b/Documentation/cgroups/cgroups.txt
> @@ -18,7 +18,8 @@ CONTENTS:
> 1.2 Why are cgroups needed ?
> 1.3 How are cgroups implemented ?
> 1.4 What does notify_on_release do ?
> - 1.5 How do I use cgroups ?
> + 1.5 What does clone_children do ?
> + 1.6 How do I use cgroups ?
> 2. Usage Examples and Syntax
> 2.1 Basic Usage
> 2.2 Attaching processes
> @@ -293,7 +294,16 @@ notify_on_release in the root cgroup at system boot is disabled
> value of their parents notify_on_release setting. The default value of
> a cgroup hierarchy's release_agent path is empty.
>
> -1.5 How do I use cgroups ?
> +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.
> +
> +1.6 How do I use cgroups ?
> --------------------------
>
> To start a new job that is to be contained within a cgroup, using
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 709dfb9..ed4ba11 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -154,6 +154,10 @@ enum {
> * A thread in rmdir() is wating for this cgroup.
> */
> CGRP_WAIT_ON_RMDIR,
> + /*
> + * Clone cgroup values when creating a new child cgroup
> + */
> + CGRP_CLONE_CHILDREN,
> };
>
> /* which pidlist file are we talking about? */
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 7b69b8d..7b17c3e 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -243,6 +243,11 @@ 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
> @@ -1039,6 +1044,8 @@ static int cgroup_show_options(struct seq_file *seq, struct vfsmount *vfs)
> seq_puts(seq, ",noprefix");
> if (strlen(root->release_agent_path))
> seq_printf(seq, ",release_agent=%s", root->release_agent_path);
> + if (clone_children(&root->top_cgroup))
> + seq_puts(seq, ",clone_children");
> if (strlen(root->name))
> seq_printf(seq, ",name=%s", root->name);
> mutex_unlock(&cgroup_mutex);
> @@ -1049,6 +1056,7 @@ struct cgroup_sb_opts {
> unsigned long subsys_bits;
> unsigned long flags;
> char *release_agent;
> + bool clone_children;
> char *name;
> /* User explicitly requested empty subsystem */
> bool none;
> @@ -1096,6 +1104,8 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
> opts->none = true;
> } else if (!strcmp(token, "noprefix")) {
> set_bit(ROOT_NOPREFIX, &opts->flags);
> + } else if (!strcmp(token, "clone_children")) {
> + opts->clone_children = true;
> } else if (!strncmp(token, "release_agent=", 14)) {
> /* Specifying two release agents is forbidden */
> if (opts->release_agent)
> @@ -1354,6 +1364,8 @@ 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);
> return root;
> }
>
> @@ -3172,6 +3184,23 @@ fail:
> return ret;
> }
>
> +static u64 cgroup_clone_children_read(struct cgroup *cgrp,
> + struct cftype *cft)
> +{
> + return clone_children(cgrp);
> +}
> +
> +static int cgroup_clone_children_write(struct cgroup *cgrp,
> + struct cftype *cft,
> + u64 val)
> +{
> + if (val)
> + set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
> + else
> + clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
> + return 0;
> +}
> +
> /*
> * for the common functions, 'private' gives the type of file
> */
> @@ -3202,6 +3231,11 @@ static struct cftype files[] = {
> .write_string = cgroup_write_event_control,
> .mode = S_IWUGO,
> },
> + {
> + .name = "cgroup.clone_children",
> + .read_u64 = cgroup_clone_children_read,
> + .write_u64 = cgroup_clone_children_write,
> + },
> };
>
> static struct cftype cft_release_agent = {
> @@ -3331,6 +3365,9 @@ 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);
> +
> for_each_subsys(root, ss) {
> struct cgroup_subsys_state *css = ss->create(ss, cgrp);
>
> @@ -3345,6 +3382,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
> goto err_destroy;
> }
> /* At error, ->destroy() callback has to free assigned ID. */
> + if (clone_children(parent) && ss->post_clone)
> + ss->post_clone(ss, cgrp);
> }
>
> cgroup_lock_hierarchy(root);
> --
> 1.7.0.4
>
>
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