Re: [PATCH v3 3/7] sched/topology: Verify SD_* flags setup when sched_debug is on

From: Peter Zijlstra
Date: Thu Jul 02 2020 - 10:20:50 EST


On Wed, Jul 01, 2020 at 08:06:51PM +0100, Valentin Schneider wrote:

> @@ -29,6 +29,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
> struct cpumask *groupmask)
> {
> struct sched_group *group = sd->groups;
> + int flags = sd->flags;

unsigned long flags = sd->flags;

>
> cpumask_clear(groupmask);
>
> @@ -43,6 +44,22 @@ 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 (; flags; flags &= flags - 1) {
> + unsigned int idx = __ffs(flags);

for_each_set_bit(idx, &flags, SD_MAX_BIT) {

Yes, it's a bit yuck, but far more readable imo.

> + 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) {
> --
> 2.27.0
>