Re: dm-bufio: Allow clients to specify an upper bound on cache size.

From: Martijn Coenen
Date: Tue Sep 10 2019 - 04:56:15 EST

Hi Mike,

On Mon, Sep 9, 2019 at 4:57 PM Mike Snitzer <snitzer@xxxxxxxxxx> wrote:
> Definitely not very intuitive.. but yes I think it is a reasonable
> tradeoff between your goals and further code complexity to be able to
> achieve the "ideal".

Thanks for the feedback. I do have a patch for the "optimal"
allocation lying around as well, if you'd like to take a look. It's
not as bad as I thought, but it does require another list_head in
dm_bufio_client; other than that it's just O(N), so not so bad.

> Think the documented example can be made clearer by documenting that
> dm_bufio_cache_size_per_client = 49. And that _that_ is the reason why
> the client that didn't set a maximum is bounded to 49.

Ack, will send a v2 to clarify.

> Overall I think this patch looks reasonable, but I'd like Mikulas to
> review this closer before I pick it up.

Thanks; let me know if you want to see the alternative as an RFC, and
I'll clean it up and send it out.


> Thanks,
> Mike