Re: [PATCH 0/4] rust: Add support for reserving of ranges of IDs

On Mon Jul 6, 2026 at 8:48 PM JST, Alice Ryhl wrote:
> On Fri, Jul 03, 2026 at 07:16:03PM +0900, Eliot Courtney wrote:
>> Add support for reserving of ranges of IDs, with a usage in nova-core
>> for channel IDs. This entails adding the helpers+users of the C bitmap
>> API for ranges of bits, then users of that in `IdPool`, and finally a
>> user of `IdPool` in nova-core, `ChannelIdPool`.
>
> If you need ranges of IDs, perhaps you want the maple tree instead?
>
> Alice

I think maple tree would work, but it looked like not as good a fit to
me because:
- the number of channel IDs is small (limited to 2048)
- allocation of a contiguous sequence of channel IDs is sometimes
  aligned to its size (which should be a power of two, AFAICT) - I
  realise patch 4 doesn't reflect this (yet). The bitmap APIs natively
  support this. 
- maple tree's alloc_range stores a value: T for the range which isn't
  necessary for ID alloc

WDYT?