On 03/08/2017 05:16 AM, Hou Tao wrote:
> When adding a cfq_group into the cfq service tree, we use CFQ_IDLE_DELAY
> as the delay of cfq_group's vdisktime if there have been other cfq_groups
> already.
>
> When cfq is under iops mode, commit 9a7f38c42c2b ("cfq-iosched: Convert
> from jiffies to nanoseconds") could result in a large iops delay and
> lead to an abnormal io schedule delay for the added cfq_group. To fix
> it, we just need to revert to the old CFQ_IDLE_DELAY value: HZ / 5
> when iops mode is enabled.
>
> Despite having the same value, the delay of a cfq_queue in idle class
> and the delay of cfq_queue are different things, so I define two new
> macros for the delay of a cfq_group under time-slice mode and IOPs mode.
Added, thanks.
--
Jens Axboe