linux-kernel - Re: [PATCH v3 3/7] sched/topology: Verify SD_* flags setup when sched

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Message-ID: <20200702142042.GI4817@hirez.programming.kicks-ass.net>
Date:   Thu, 2 Jul 2020 16:20:42 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Valentin Schneider <valentin.schneider@....com>
Cc:     linux-kernel@...r.kernel.org, mingo@...nel.org,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        morten.rasmussen@....com
Subject: Re: [PATCH v3 3/7] sched/topology: Verify SD_* flags setup when
 sched_debug is on

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
>