Re: [PATCH v8 0/5] Initial support for multi-actuator HDDs

[Jens Axboe <axboe@kernel.dk>]

On 9/8/21 8:35 PM, Damien Le Moal wrote:
> Single LUN multi-actuator hard-disks are cappable to seek and execute
> multiple commands in parallel. This capability is exposed to the host
> using the Concurrent Positioning Ranges VPD page (SCSI) and Log (ATA).
> Each positioning range describes the contiguous set of LBAs that an
> actuator serves.
> 
> This series adds support to the scsi disk driver to retreive this
> information and advertize it to user space through sysfs. libata is
> also modified to handle ATA drives.
> 
> The first patch adds the block layer plumbing to expose concurrent
> sector ranges of the device through sysfs as a sub-directory of the
> device sysfs queue directory. Patch 2 and 3 add support to sd and
> libata. Finally patch 4 documents the sysfs queue attributed changes.
> Patch 5 fixes a typo in the document file (strictly speaking, not
> related to this series).
> 
> This series does not attempt in any way to optimize accesses to
> multi-actuator devices (e.g. block IO schedulers or filesystems). This
> initial support only exposes the independent access ranges information
> to user space through sysfs.

Let's get this queued up for 5.16. I forgot what we agreed upon, can go
either block or SCSI. We likely have a bunch more block changes this
round than usual, and hence a higher risk of conflict, so from that
perspective alone I think the block layer would be easier.

In any case, Damien, it needs a respin as it doesn't apply against
my for-5.16/block at this point.

-- 
Jens Axboe