On 5/23/23 02:03, Ming Lei wrote:
On Mon, May 22, 2023 at 11:38:37AM -0700, Bart Van Assche wrote:
Send requeued requests to the I/O scheduler such that the I/O scheduler
can control the order in which requests are dispatched.
I guess you are addressing UFS zoned for REQ_OP_WRITE:
https://lore.kernel.org/linux-block/8e88b22e-fdf2-5182-02fe-9876e8148947@xxxxxxx/
I am wondering how this way can maintain order for zoned write request.
requeued WRITE may happen in any order, for example, req A and req B is
in order, now req B is requeued first, then follows req A.
So req B is requeued to scheduler first, and issued to LLD, then
request A is requeued and issued to LLD later, then still re-order?
Or sd_zbc can provide requeue order guarantee?
Hi Ming,
The mq-deadline scheduler restricts the queue depth to one per zone for zoned
storage so at any time there is at most one write command (REQ_OP_WRITE) in
flight per zone.
Thanks,
Bart.
