linux-kernel - [PATCH 1/2] sched/deadline: use online cpus for validating runtime

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Message-ID: <20250306052954.452005-2-sshegde@linux.ibm.com>
Date: Thu,  6 Mar 2025 10:59:53 +0530
From: Shrikanth Hegde <sshegde@...ux.ibm.com>
To: juri.lelli@...hat.com, linux-kernel@...r.kernel.org
Cc: sshegde@...ux.ibm.com, mingo@...nel.org, peterz@...radead.org,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
        vschneid@...hat.com, hbathini@...ux.ibm.com, joelagnelf@...dia.com
Subject: [PATCH 1/2] sched/deadline: use online cpus for validating runtime

ftrace selftest reported failure since writing -1 to sched_rt_runtime_us
return -EBUSY. This happens when the possible CPUs is different than
the 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 validation the
bandwidth calculations.

Signed-off-by: Shrikanth Hegde <sshegde@...ux.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 2d0f571f95e9..7ea9c040c72f 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -3187,7 +3187,7 @@ 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))
-- 
2.39.3