On Tue, Nov 29, 2022 at 11:01:39AM +0800, Kemeng Shi wrote: > Consider situation as following (on the default hierarchy): > HDD > | > root (bps limit: 4k) > | > child (bps limit :8k) > | > fio bs=8k > Rate of fio is supposed to be 4k, but result is 8k. Reason is as > following: > Size of single IO from fio is larger than bytes allowed in one > throtl_slice in child, so IOs are always queued in child group first. > When queued IOs in child are dispatched to parent group, BIO_BPS_THROTTLED > is set and these IOs will not be limited by tg_within_bps_limit anymore. > Fix this by only set BIO_BPS_THROTTLED when the bio traversed the entire > tree. > > There patch has no influence on situation which is not on the default > hierarchy as each group is a single root group without parent. > > Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxx> Acked-by: Tejun Heo <tj@xxxxxxxxxx> -- tejun
