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charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Oct 22, 2026 at 10:49:36AM -0700, Josh Don wrote: > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index b5546cd27dba..779fcd5a2830 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -15767,6 +15767,40 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) > > return ret; > > } > > > > +struct tg_set_idle_struct { > > + long idle; > > + int cpu; > > +}; > > + > > +static int tg_set_idle_up(struct task_group *tg, void *data) > > +{ > > + struct tg_set_idle_struct *tsi = data; > > + struct cfs_rq *grp_cfs_rq = tg_cfs_rq(tg, tsi->cpu); > > + struct sched_entity *se = tg_se(tg, tsi->cpu); > > + int old_idle = grp_cfs_rq->idle; > > + long task_delta; > > + > > + grp_cfs_rq->idle += tsi->idle; > > + > > + if (!!old_idle == !!grp_cfs_rq->idle) > > + return 0; > > + > > + task_delta = grp_cfs_rq->h_nr_queued - grp_cfs_rq->h_nr_idle; > > + if (!task_delta) > > + return 0; > > + > > + task_delta *= tsi->idle; > > + > > + for_each_sched_entity(se) { > > + if (!se->on_rq) > > + break; > > + > > + cfs_rq_of(se)->h_nr_idle += task_delta; > > + } > > + > > + return 0; > > +} > > Took me a bit to parse this double traversal. I think this is broken > for the clear side? > > root > | > A ( 2 tasks) > | > B (3 tasks) > > If we start out with A marked as idle, then we have > root: h_nr_idle = 5 > A: h_nr_idle = 3 > B: h_nr_idle = 0 > > When we clear, we'll first start with B and subtract 3... > root: h_nr_idle = 2 > A: h_nr_idle = 0 > B: h_nr_idle = 0 > > Then we go to A and try to subtract 5 leading to > root: h_nr_idle = -3 > Argh. Yes, I seem to have gotten it wrong. I'll try again in the morning.