cgroup: add clone_children control file

[mv-sheeva.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 9270d532ec3c7c6a5be2cf3d1eca21788036b81f..4b218a46ddd3d631e1ec92ded13e01b548aba346 100644 (file)
--- 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
@@ -1040,6 +1045,8 @@ 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);
@@ -1050,6 +1057,7 @@ 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;
@@ -1097,6 +1105,8 @@ 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)
@@ -1355,6 +1365,8 @@ 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;
 }
 
@@ -3173,6 +3185,23 @@ 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
  */
@@ -3203,6 +3232,11 @@ 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 = {
@@ -3332,6 +3366,9 @@ 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);
 
@@ -3346,6 +3383,8 @@ 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);