Re: [RFC PATCH v2 0/8] kvfree_rcu() improvements

["Harry Yoo (Oracle)" <harry@kernel.org>]

On Wed, Apr 22, 2026 at 04:30:07PM +0200, Vlastimil Babka (SUSE) wrote:
> On 4/16/26 11:10, Harry Yoo (Oracle) wrote:
> > # Part 1. Allow an 8-byte field to be used as an alternative to
> >   struct rcu_head for 2-argument kvfree_rcu()
> >   (patches 1-2)
> > 
> > Technically, objects that are freed with k[v]free_rcu() need
> > only one pointer to link objects, because we already know that
> > the callback function is always kvfree(). For this purpose,
> > struct rcu_head is unnecessarily large (16 bytes on 64-bit).
> > 
> > Allow a smaller, 8-byte field (of struct rcu_ptr type) to be used
> > with k[v]free_rcu(). Let's save one pointer per slab object.
> > 
> > I have to admit that my naming skill isn't great; hopefully
> > we'll come up with a better name than `struct rcu_ptr`.
> 
> "rcu_ptr" sounds too generic to me.

to me too ;)

> Things like rcu_dereference() talk about
> "RCU-protected pointer" and it could be misleading that "rcu_ptr" has
> something to do with this.

Agreed.

> But maybe just "kvfree_rcu_head"? As IMHO It's an rcu_head specialized for
> kvfree.

I like the name better and will rename it, thanks!

-- 
Cheers,
Harry / Hyeonggon