linux-kernel - [RFC][PATCH 14/16] sched/fair: Add a few assertions

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Date:   Mon, 18 Feb 2019 17:56:34 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     mingo@...nel.org, tglx@...utronix.de, pjt@...gle.com,
        tim.c.chen@...ux.intel.com, torvalds@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, subhra.mazumdar@...cle.com,
        fweisbec@...il.com, keescook@...omium.org, kerrnel@...gle.com,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>
Subject: [RFC][PATCH 14/16] sched/fair: Add a few assertions


Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/sched/fair.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6208,6 +6208,11 @@ static int select_idle_sibling(struct ta
 	struct sched_domain *sd;
 	int i, recent_used_cpu;
 
+	/*
+	 * per-cpu select_idle_mask usage
+	 */
+	lockdep_assert_irqs_disabled();
+
 	if (available_idle_cpu(target))
 		return target;
 
@@ -6635,8 +6640,6 @@ 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 sd_flag, int wake_flags)
@@ -6647,6 +6650,11 @@ select_task_rq_fair(struct task_struct *
 	int want_affine = 0;
 	int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING);
 
+	/*
+	 * required for stable ->cpus_allowed
+	 */
+	lockdep_assert_held(&p->pi_lock);
+
 	if (sd_flag & SD_BALANCE_WAKE) {
 		record_wakee(p);