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Commit 1f869e87 authored by Glauber Costa's avatar Glauber Costa Committed by Tejun Heo
Browse files

cgroup: warn about broken hierarchies only after css_online 



If everything goes right, it shouldn't really matter if we are spitting
this warning after css_alloc or css_online. If we fail between then,
there are some ill cases where we would previously see the message and
now we won't (like if the files fail to be created).

I believe it really shouldn't matter: this message is intended in spirit
to be shown when creation succeeds, but with insane settings.

Signed-off-by: default avatarGlauber Costa <glommer@parallels.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 9718ceb3

kernel/cgroup.c

+9 −9
Original line number Diff line number Diff line
@@ -4151,15 +4151,6 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, 
			if (err)

				goto err_free_all;

		}



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

		    parent->parent) {

			pr_warning("cgroup: %s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",

				   current->comm, current->pid, ss->name);

			if (!strcmp(ss->name, "memory"))

				pr_warning("cgroup: \"memory\" requires setting use_hierarchy to 1 on the root.\n");

			ss->warned_broken_hierarchy = true;

		}

	}



	/*
@@ -4188,6 +4179,15 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, 
		err = online_css(ss, cgrp);

		if (err)

			goto err_destroy;



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

		    parent->parent) {

			pr_warning("cgroup: %s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",

				   current->comm, current->pid, ss->name);

			if (!strcmp(ss->name, "memory"))

				pr_warning("cgroup: \"memory\" requires setting use_hierarchy to 1 on the root.\n");

			ss->warned_broken_hierarchy = true;

		}

	}



	err = cgroup_populate_dir(cgrp, true, root->subsys_mask);