linux-kernel - [tip: sched/urgent] sched/deadline: Use online cpus for validating runtime

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Message-ID: <174125536534.14745.5263095159289087777.tip-bot2@tip-bot2>
Date: Thu, 06 Mar 2025 10:02:45 -0000
From: "tip-bot2 for Shrikanth Hegde" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Shrikanth Hegde <sshegde@...ux.ibm.com>, Ingo Molnar <mingo@...nel.org>,
 Juri Lelli <juri.lelli@...hat.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject:
 [tip: sched/urgent] sched/deadline: Use online cpus for validating runtime

The following commit has been merged into the sched/urgent branch of tip:

Commit-ID:     14672f059d83f591afb2ee1fff56858efe055e5a
Gitweb:        https://git.kernel.org/tip/14672f059d83f591afb2ee1fff56858efe055e5a
Author:        Shrikanth Hegde <sshegde@...ux.ibm.com>
AuthorDate:    Thu, 06 Mar 2025 10:59:53 +05:30
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Thu, 06 Mar 2025 10:21:31 +01:00

sched/deadline: Use online cpus for validating runtime

The ftrace selftest reported a failure because writing -1 to
sched_rt_runtime_us returns -EBUSY. This happens when the possible
CPUs are different from active CPUs.

Active CPUs are part of one root domain, while remaining CPUs are part
of def_root_domain. Since active cpumask is being used, this results in
cpus=0 when a non active CPUs is used in the loop.

Fix it by looping over the online CPUs instead for validating the
bandwidth calculations.

Signed-off-by: Shrikanth Hegde <sshegde@...ux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Reviewed-by: Juri Lelli <juri.lelli@...hat.com>
Link: https://lore.kernel.org/r/20250306052954.452005-2-sshegde@linux.ibm.com
---
 kernel/sched/deadline.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 38e4537..ff4df16 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -3189,7 +3189,7 @@ int sched_dl_global_validate(void)
 	 * value smaller than the currently allocated bandwidth in
 	 * any of the root_domains.
 	 */
-	for_each_possible_cpu(cpu) {
+	for_each_online_cpu(cpu) {
 		rcu_read_lock_sched();
 
 		if (dl_bw_visited(cpu, gen))