On Thu, Nov 14, 2024 at 02:28:09PM +0000 Juri Lelli wrote: > When root domain non-destructive changes (e.g., only modifying one of > the existing root domains while the rest is not touched) happen we still > need to clear DEADLINE bandwidth accounting so that it's then properly > restored, taking into account DEADLINE tasks associated to each cpuset > (associated to each root domain). After the introduction of dl_servers, > we fail to restore such servers contribution after non-destructive > changes (as they are only considered on destructive changes when > runqueues are attached to the new domains). > > Fix this by making sure we iterate over the dl_servers attached to > domains that have not been destroyed and add their bandwidth > contribution back correctly. > > Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx> > Reviewed-by: Phil Auld <pauld@xxxxxxxxxx> > --- > v1->v2: always restore, considering a root domain span (and check for > active cpus) > --- > kernel/sched/deadline.c | 17 ++++++++++++++--- > kernel/sched/topology.c | 8 +++++--- > 2 files changed, 19 insertions(+), 6 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 9ce93d0bf452..a9cdbf058871 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -2970,11 +2970,22 @@ void dl_add_task_root_domain(struct task_struct *p) > > void dl_clear_root_domain(struct root_domain *rd) > { > - unsigned long flags; > + int i; > > - raw_spin_lock_irqsave(&rd->dl_bw.lock, flags); > + guard(raw_spinlock_irqsave)(&rd->dl_bw.lock); > rd->dl_bw.total_bw = 0; > - raw_spin_unlock_irqrestore(&rd->dl_bw.lock, flags); > + > + /* > + * dl_server bandwidth is only restored when CPUs are attached to root > + * domains (after domains are created or CPUs moved back to the > + * default root doamin). > + */ > + for_each_cpu(i, rd->span) { > + struct sched_dl_entity *dl_se = &cpu_rq(i)->fair_server; > + > + if (dl_server(dl_se) && cpu_active(i)) > + rd->dl_bw.total_bw += dl_se->dl_bw; > + } > } > > #endif /* CONFIG_SMP */ > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 9748a4c8d668..9c405f0e7b26 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -2721,9 +2721,11 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[], > > /* > * This domain won't be destroyed and as such > - * its dl_bw->total_bw needs to be cleared. It > - * will be recomputed in function > - * update_tasks_root_domain(). > + * its dl_bw->total_bw needs to be cleared. > + * Tasks contribution will be then recomputed > + * in function dl_update_tasks_root_domain(), > + * dl_servers contribution in function > + * dl_restore_server_root_domain(). > */ > rd = cpu_rq(cpumask_any(doms_cur[i]))->rd; > dl_clear_root_domain(rd); > -- > 2.47.0 > --