linux-kernel - [PATCH 01/19] sched/fair: Add a few assertions

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Message-ID: <20210422123308.015639083@infradead.org>
Date:   Thu, 22 Apr 2021 14:05:00 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     joel@...lfernandes.org, chris.hyser@...cle.com, joshdon@...gle.com,
        mingo@...nel.org, vincent.guittot@...aro.org,
        valentin.schneider@....com, mgorman@...e.de
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        tglx@...utronix.de
Subject: [PATCH 01/19] sched/fair: Add a few assertions


Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/sched/fair.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6246,6 +6246,11 @@ static int select_idle_sibling(struct ta
 		task_util = uclamp_task_util(p);
 	}
 
+	/*
+	 * per-cpu select_idle_mask usage
+	 */
+	lockdep_assert_irqs_disabled();
+
 	if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
 	    asym_fits_capacity(task_util, target))
 		return target;
@@ -6711,8 +6716,6 @@ static int find_energy_efficient_cpu(str
  * certain conditions an idle sibling CPU if the domain has SD_WAKE_AFFINE set.
  *
  * Returns the target CPU number.
- *
- * preempt must be disabled.
  */
 static int
 select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
@@ -6725,6 +6728,10 @@ select_task_rq_fair(struct task_struct *
 	/* SD_flags and WF_flags share the first nibble */
 	int sd_flag = wake_flags & 0xF;
 
+	/*
+	 * required for stable ->cpus_allowed
+	 */
+	lockdep_assert_held(&p->pi_lock);
 	if (wake_flags & WF_TTWU) {
 		record_wakee(p);