Re: [PATCH v3 01/18] block: introduce duration-limits priority class

Bart Van Assche
2023-01-30T19:13:30Z

On 1/28/23 12:25, Martin K. Petersen wrote:
> - Wrt. ioprio as conduit, I personally really dislike the idea of
> conflating priority (relative performance wrt. other I/O) with CDL
> (which is a QoS concept). I would really prefer those things to be
> separate. However, I do think that the ioprio *interface* is a good
> fit. A tool like ionice seems like a reasonable approach to letting
> generic applications set their CDL.

Hi Martin,

My understanding is that ionice uses the ioprio_set() system call and
hence only affects foreground I/O but not page cache writeback. This is
why I introduced the ioprio rq-qos policy (block/blk-ioprio.c). How
about not adding CDL support in ioprio_set() and only supporting
configuration of CDL via the v2 cgroup mechanism?

Thanks,

Bart.