Re: [PATCH v4 7/7] net: register debugfs file for net_device refcnt tracker

[Andrew Lunn]

On Thu, Apr 24, 2025 at 06:56:06AM -0400, Jeff Layton wrote:
> On Wed, 2025-04-23 at 17:32 -0700, Jakub Kicinski wrote:
> > On Wed, 23 Apr 2025 20:04:58 -0400 Jeff Layton wrote:
> > > On Wed, 2025-04-23 at 16:53 -0700, Jakub Kicinski wrote:
> > > > Names are not unique and IIUC debugfs is not namespaced.
> 
> Correct, debugfs is not namespaced.
> 
> I meant to say earlier that I'm open to suggestions on how to make the
> netdev names unique. Low-level netdev stuff is not my area of
> expertise. We can drop this patch if doing so is problematic.
> 
> > > > How much naming the objects in a "user readable" fashion actually
> > > > matter? It'd be less churn to create some kind of "object class"
> > > > with a directory level named after what's already passed to
> > > > ref_tracker_dir_init() and then id the objects by the pointer value 
> > > > as sub-dirs of that?  
> > > 
> > > That sounds closer to what I had done originally. Andrew L. suggested
> > > the flat directory that this version represents. I'm fine with whatever
> > > hierarchy, but let's decide that before I respin again.
> > 
> > Sorry about that :(
> > 
> 
> No worries...but we do need to decide what this directory hierarchy
> should look like.
> 
> Andrew's point earlier was that this is just debugfs, so a flat
> "ref_tracker" directory full of files is fine. I tend to agree with
> him; NAME_MAX is 255, so we have plenty of room to make uniquely-named
> files.
> 
> We could build a dir hierarchy though. Something like:
> 
> - ref_tracker
>     + netdev
>     + netns

How do you make that generic? How due the GPU users of reftracker fit
in? And whatever the next users are? A flat directory keeps it
simple. Anybody capable of actually using this has to have a level of
intelligence sufficient for glob(3).

However, a varargs format function does make sense, since looking at
the current users, many of them will need it.

	Andrew