From 3aebcda8d60dbfed4f41854c66492d099e12de31 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 14 Apr 2017 18:20:48 +0200
Subject: [PATCH] sched/topology: Verify the first group matches the child
 domain

References: bnc#978907 Scheduler performance -- topology
Patch-mainline: v4.13-rc1
Git-commit: a420b0630362c2c451060e6187e36d72df827134

We want sched_groups to be sibling child domains (or individual CPUs
when there are no child domains). Furthermore, since the first group
of a domain should include the CPU of that domain, the first group of
each domain should match the child domain.

Verify this is indeed so.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 kernel/sched/topology.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 7a6e9f477702..22355d0cc5eb 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -93,6 +93,12 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
 				group->sgc->capacity);
 		}
 
+		if (group == sd->groups && sd->child &&
+		    !cpumask_equal(sched_domain_span(sd->child),
+				   sched_group_cpus(group))) {
+			printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n");
+		}
+
 		group = group->next;
 
 		if (group != sd->groups)