Re: [PATCH 2/4] kernfs: make kernfs_path*() behave in the style of strlcpy()

[Serge E. Hallyn]

Quoting Tejun Heo (tj@xxxxxxxxxx):
> Hello, Serge.
> 
> On Tue, Aug 09, 2016 at 10:33:05AM -0500, Serge E. Hallyn wrote:
> > > +	for (i = depth_to - 1; i >= 0; i--) {
> > > +		for (kn = kn_to, j = 0; j < i; j++)
> > > +			kn = kn->parent;
> > 
> > This is O(n^2) where n is the path depth.  It's not a hot path, though, do
> > we care?
> 
> I don't think it matters.  It's a slow path and cgroup hierarchies
> aren't supposed to be super deep to begin with.  If it ever does, we
> can replace the cgroup->ancestor_ids[] array with ancestor pointer
> array and walk that instead.
> 
> Thanks.

Ok, thanks

Acked-by: Serge Hallyn <serge@xxxxxxxxxx>