6.12-stable review patch. If anyone has any objections, please let me know.
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From: Juri Lelli juri.lelli@redhat.com
commit 41d4200b7103152468552ee50998cda914102049 upstream.
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@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Phil Auld pauld@redhat.com Tested-by: Waiman Long longman@redhat.com Link: https://lore.kernel.org/r/20241114142810.794657-2-juri.lelli@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sched/deadline.c | 17 ++++++++++++++--- kernel/sched/topology.c | 8 +++++--- 2 files changed, 19 insertions(+), 6 deletions(-)
--- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2975,11 +2975,22 @@ void dl_add_task_root_domain(struct task
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 */ --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -2721,9 +2721,11 @@ void partition_sched_domains_locked(int
/* * 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);