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

Bart Van Assche
2024-10-03T22:00:32Z

On 10/3/24 2:48 PM, Keith Busch wrote:
> The only "bonus" I have is not repeatedly explaining why people can't
> use h/w features the way they want.

Hi Keith,

Although that's a fair argument, what are the use cases for this patch
series? Filesystems in the kernel? Filesystems implemented in user
space? Perhaps something else?

This patch series adds new a new user space interface for passing hints
to storage devices (in io_uring). As we all know such interfaces are
hard to remove once these have been added.

We don't need new user space interfaces to support FDP for filesystems
in the kernel.

For filesystems implemented in user space, would using NVMe pass-through
be a viable approach? With this approach, no new user space interfaces
have to be added.

I'm wondering how to unblock FDP users without adding a new
controversial mechanism in the kernel.

Thanks,

Bart.