Re: Another approach of UFSHPB

[Bart Van Assche]

On 2020-05-24 22:40, Daejun Park wrote:
> The HPB driver is close to the UFS core function, but it is not essential
> for operating UFS device. With reference to this article
> (https://lwn.net/Articles/645810/), we implemented extended UFS-feature
> as bus model. Because the HPB driver consumes the user's main memory, it should
> support bind / unbind functionality as needed. We implemented the HPB driver 
> can be unbind / unload on runtime.

I do not agree that the bus model is the best choice for freeing cache
memory if it is no longer needed. A shrinker is probably a much better
choice because the callback functions in a shrinker get invoked when a
system is under memory pressure. See also register_shrinker(),
unregister_shrinker() and struct shrinker in include/linux/shrinker.h.

>> Should these parameters be per module or per UFS device?
> 
> I think it is necessary to take parameters for each module. 
> This is because each extended UFS-feature module has different functions
> and may require different parameters.

My question was a rhetorical question. Please choose per device
parameters when appropriate instead of module parameters.

Thanks,

Bart.