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.
