On Tue, Oct 11, 2022 at 04:35:46PM +0800, Yu Kuai wrote: > From: Yu Kuai <yukuai3@xxxxxxxxxx> > > In this special case, there is no need to throttle io. > > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> > --- > block/blk-iocost.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/block/blk-iocost.c b/block/blk-iocost.c > index 5acc5f13bbd6..32e7e416d67c 100644 > --- a/block/blk-iocost.c > +++ b/block/blk-iocost.c > @@ -2564,8 +2564,13 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio) > bool use_debt, ioc_locked; > unsigned long flags; > > - /* bypass IOs if disabled, still initializing, or for root cgroup */ > - if (!ioc->enabled || !iocg || !iocg->level) > + /* > + * bypass IOs if disabled, still initializing, for root cgroup, > + * or the cgroup is the only cgroup with io. > + */ > + if (!ioc->enabled || !iocg || !iocg->level || > + (iocg->hweight_inuse == WEIGHT_ONE && > + atomic_read(&ioc->hweight_gen) == iocg->hweight_gen)) I'm not sure about this one. Bypassing here means that we lose track of how much IO it's issuing which can affect future throttling decisions, right? Thanks. -- tejun
