cgroup: try to set clone_children

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
index 4d7de02f384697704f990ec1953fc124db11c1aa..2044c2b64e10fdd8a3c203b7ec0db4cc20e32bf1 100644 (file)
--- a/src/lxc/cgroup.c
+++ b/src/lxc/cgroup.c
@@ -557,6 +557,31 @@ out:
        free(parentpath);
 }
 
+/*
+ * If first creating the /sys/fs/cgroup/$subsys/lxc container, then
+ * try to set clone_children to 1.  Some kernels don't support
+ * clone_children, and cgroup maintainer wants to deprecate it.  So
+ * XXX TODO we should instead after each cgroup mkdir (here and in
+ * hooks/mountcgroup) check if cpuset is in the subsystems, and if so
+ * manually copy over mems and cpus.
+ */
+static void set_clone_children(const char *mntdir, const char *init)
+{
+       char path[MAXPATHLEN];
+       FILE *fout;
+       int ret;
+
+       ret = snprintf(path, MAXPATHLEN, "%s%s/cgroup.clone_children", mntdir, init);
+       INFO("writing to %s\n", path);
+       if (ret < 0 || ret > MAXPATHLEN)
+               return;
+       fout = fopen(path, "w");
+       if (!fout)
+               return;
+       fprintf(fout, "1\n");
+       fclose(fout);
+}
+
 /*
  * Make sure the 'cgroup group' exists, so that we don't have to worry about
  * that later.
@@ -597,6 +622,7 @@ static int create_lxcgroups(const char *lxcgroup)
                if (ret < 0 || ret >= MAXPATHLEN)
                        goto fail;
                if (access(path, F_OK)) {
+                       set_clone_children(mntent->mnt_dir, init);
                        ret = mkdir(path, 0755);
                        if (ret == -1 && errno != EEXIST) {
                                SYSERROR("failed to create '%s' directory", path);