Re: [PATCH v7 0/3] FDP and per-io hints

Christoph Hellwig
2024-10-17T15:46:55Z

On Thu, Oct 17, 2024 at 09:44:39AM -0600, Keith Busch wrote:
> I'm replying just to make sure I understand what you're saying:
>
> If we send per IO hints on a file, we could have interleaved hot and
> cold pages at various offsets of that file, so the filesystem needs an
> efficient way to allocate extents and track these so that it doesn't
> interleave these in LBA space. I think that makes sense.

That's a little simplified, but yes.

> We can add a fop_flags and block/fops.c can be the first one to turn it
> on since that LBA access is entirely user driven.

Yes, that's my main request on the per-I/O hint interface.

Now we just need to not dumb down the bio level interface to five
temeperature level and just expose the different write streams and we
can all have a happy Kumbaya.