[tip: sched/core] sched/topology: Verify SD_* flags setup when sched_debug is on

[tip-bot2 for Valentin Schneider]

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

Commit-ID:     65c5e253168dbbb52c20026b0c5b7a2f344b9197
Gitweb:        https://git.kernel.org/tip/65c5e253168dbbb52c20026b0c5b7a2f344b9197
Author:        Valentin Schneider <valentin.schneider@xxxxxxx>
AuthorDate:    Mon, 17 Aug 2020 12:29:51 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 19 Aug 2020 10:49:48 +02:00

sched/topology: Verify SD_* flags setup when sched_debug is on

Now that we have some description of what we expect the flags layout to
be, we can use that to assert at runtime that the actual layout is sane.

Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: https://lore.kernel.org/r/20200817113003.20802-6-valentin.schneider@xxxxxxx
---
 kernel/sched/topology.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index fe03969..cbdaf08 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -29,6 +29,8 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
 				  struct cpumask *groupmask)
 {
 	struct sched_group *group = sd->groups;
+	unsigned long flags = sd->flags;
+	unsigned int idx;
 
 	cpumask_clear(groupmask);
 
@@ -43,6 +45,21 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
 		printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu);
 	}
 
+	for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
+		unsigned int flag = BIT(idx);
+		unsigned int meta_flags = sd_flag_debug[idx].meta_flags;
+
+		if ((meta_flags & SDF_SHARED_CHILD) && sd->child &&
+		    !(sd->child->flags & flag))
+			printk(KERN_ERR "ERROR: flag %s set here but not in child\n",
+			       sd_flag_debug[idx].name);
+
+		if ((meta_flags & SDF_SHARED_PARENT) && sd->parent &&
+		    !(sd->parent->flags & flag))
+			printk(KERN_ERR "ERROR: flag %s set here but not in parent\n",
+			       sd_flag_debug[idx].name);
+	}
+
 	printk(KERN_DEBUG "%*s groups:", level + 1, "");
 	do {
 		if (!group) {