v2: ToggleControllers() should toggle ancestors of c.path, not c.path itself

[AkihiroSuda]

cgroups/v2/manager.go

Line 192 in e56683d

func (c *Manager) ToggleControllers(controllers []string, t ControllerToggle) error {

ToggleControllers() should toggle ancestors of c.path, not c.path itself.

e.g. when c.path is like /foo/bar/baz, the following files need to be written:

• /sys/fs/cgroup/foo/cgroup.subtree_control
• /sys/fs/cgroup/foo/bar/cgroup.subtree_control

Note that /sys/fs/cgroup/foo/bar/baz/cgroup.subtree_control does not need to be written.

[AkihiroSuda]

Aside from this, ToggleControllers() should return map[string]error rather than just single err.

[crosbymichael]

Noooo, map[string]error is a horrible ux, there are better ways to handle this

[AkihiroSuda]

like this then?

// toggleError implements error interface
type toggleError struct {
  failed map[string]struct{}
}

func (e toggleError) Error() string{
}

func (e toggleError) FailedControllers() map[string]struct{}{
}