Re: [PATCH 09/13] block: introduce blkdev_report_zones_cached()

Damien Le Moal
2025-11-03T07:18:18Z

On 11/1/25 06:53, Bart Van Assche wrote:
> On 10/30/25 11:13 PM, Damien Le Moal wrote:
>> Introduce the function blkdev_report_zones_cached() to provide a fast
>> report zone built using the blkdev_get_zone_info() function, which gets
>> zone information from a disk zones_cond array or zone write plugs.
>> For a large capacity SMR drive, such fast report zone can be completed
>> in a few millioseconds compared to several seconds completion times
>> when the report zone is obtained from the device.
>
> millioseconds -> milliseconds
>
> Does retrieving the cached zone information really require multiple
> milliseconds instead of only a few microseconds?

There are over 100,000 zones on large capacity SMR HDDs. And I have models with
smaller zone size that have over 200,000 zones. So yes, a few milliseconds are
needed on normal (read not super fast) CPUs.

--
Damien Le Moal
Western Digital Research