Re: [PATCH RFC 0/8] Introduce provisioning primitives for thinly provisioned storage

Bart Van Assche
2022-09-16T20:01:26Z

On 9/16/22 11:48, Sarthak Kukreti wrote:
> Yes. On ChromiumOS, we regularly deal with storage devices that don't
> support WRITE_ZEROES or that need to have it disabled, via a quirk,
> due to a bug in the vendor's implementation. Using WRITE_ZEROES for
> allocation makes the allocation path quite slow for such devices (not
> to mention the effect on storage lifetime), so having a separate
> provisioning construct is very appealing. Even for devices that do
> support an efficient WRITE_ZEROES implementation but don't support
> logical provisioning per-se, I suppose that the allocation path might
> be a bit faster (the device driver's request queue would report
> 'max_provision_sectors'=0 and the request would be short circuited
> there) although I haven't benchmarked the difference.

Some background information about why ChromiumOS uses thin provisioning
instead of a single filesystem across the entire storage device would be
welcome. Although UFS devices support thin provisioning I am not aware
of any use cases in Android that would benefit from UFS thin
provisioning support.

Thanks,

Bart.