sched/deadline: Fix accounting after global limits change

[ Upstream commit 440989c10f ]

A global limits change (sched_rt_handler() logic) currently leaves stale
and/or incorrect values in variables related to accounting (e.g.
extra_bw).

Properly clean up per runqueue variables before implementing the change
and rebuild scheduling domains (so that accounting is also properly
restored) after such a change is complete.

Reported-by: Marcel Ziswiler <marcel.ziswiler@codethink.co.uk>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@codethink.co.uk> # nuc & rock5b
Link: https://lore.kernel.org/r/20250627115118.438797-4-juri.lelli@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Juri Lelli 2025-06-27 13:51:16 +02:00 committed by Greg Kroah-Hartman
parent 9876183788
commit 1b9f54ac0b
2 changed files with 9 additions and 1 deletions

View File

@ -3227,6 +3227,9 @@ void sched_dl_do_global(void)
if (global_rt_runtime() != RUNTIME_INF)
new_bw = to_ratio(global_rt_period(), global_rt_runtime());
for_each_possible_cpu(cpu)
init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl);
for_each_possible_cpu(cpu) {
rcu_read_lock_sched();
@ -3242,7 +3245,6 @@ void sched_dl_do_global(void)
raw_spin_unlock_irqrestore(&dl_b->lock, flags);
rcu_read_unlock_sched();
init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl);
}
}

View File

@ -2951,6 +2951,12 @@ undo:
}
mutex_unlock(&mutex);
/*
* After changing maximum available bandwidth for DEADLINE, we need to
* recompute per root domain and per cpus variables accordingly.
*/
rebuild_sched_domains();
return ret;
}