[PATCH RFC 0/2] rcu box container for Rust + maple tree load_rcu

[Boqun Feng]

On Sat, Jan 17, 2026 at 01:29:25PM +0000, Alice Ryhl wrote:
> On Sat, Jan 17, 2026 at 09:11:49PM +0800, Boqun Feng wrote:
> > In Rcu + RcuOld design, RcuBox is just a Box
> > because these two pointer types handle reclaim + accesses.
> 
> How would that work? Dropping my RcuBox<_> must use kfree_rcu() or
> synchronize_rcu() or it is unsound. So it can't just be a Box.
> 

RcuOld<P: ForeignOwnable> will call synchronize_rcu() before dropping
`P`. And I think we can have an asynchronous drop pointer type like
`RcuOld<P, Async>` that requires `P` is a type like `Box<HasRcuHead>`,
and the drop of `RcuOld<Box<HasRcuHead>, Async>` would be `call_rcu()`
or `kfree_rcu()`.

Regards,
Boqun

> Alice