Re: [RFC v1 4/4] xfs: Add support to shrink multiple empty realtime groups

Nirjhar Roy (IBM)
2026-02-26T12:59:42Z

On Wed, 2026-02-25 at 06:24 -0800, Christoph Hellwig wrote:
> On Wed, Feb 25, 2026 at 10:47:40AM +0530, Nirjhar Roy (IBM) wrote:
> > > Highlevel note: this seems to only cover classic bitmap based RTGs,
> > > and not zoned ones. You might want to look into the latter because
> >
> > Okay. So are you suggesting to add the shrink support only for the
> > zoned devices or extend this patch set to cover shrink for the zoned
> > devices too?
>
> We should support all devices. But what I'm trying to say is the
> zoned version is both simpler, and will actually allow you to get
> to an actually useful fully feature shink much more easily.

Okay. I will start taking a look at it.
>
> > > they're actually much simpler, and with the zoned GC code we actually
> > > have a super nice way to move data out of the RTG. I'd be happy to
> > > supple you a code sniplet for the latter.
> >
> > Sure, that would be super useful. Also, since I don't have much
> > experience in zoned devices, can you please point to some relevant
> > resources and recent zoned device related patchsets that can help me
> > get started with?
>
> You don't actually need a zoned device, you can just mkfs with
> "-r zoned=1" and get a internal rtdevice configuration. If you are

Oh nice!.
> interested in the actual hardware and ecosystem take a look at:
> https://zonedstorage.io/
>
> If at some point you're interested in hardware samples contact me
> offlist and I'll connect you to the right people.

Thank you for the pointers.
--NR
>