On Thu, Jan 19, 2023 at 07:03:31AM -1000, Tejun Heo wrote:

On Tue, Jan 17, 2023 at 09:12:42AM +0100, Christoph Hellwig wrote:

quoted

blk-cgroup works on only on live disks and "file system" I/O from bios.
This all the information should be in the gendisk, and not the
request_queue that also exists for pure passthrough request based
devices.

Can't blk-throttle be used w/ bio based ones tho? I always thought that was
the reason why we didn't move it into rq-qos framework.

Yes, it can.  Not sure if my sentence was unclear, but:

 - everything doing non-passthrough I/O only should be in the gendisk
 - everything related to blk-mq, including infrastruture for passthrough
   should remain in the request_queue

The idea that the request_queue will eventually become a blk-mq only
data structure and not exist (or just have a very leight weight stub)
for bio based drivers.