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

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Message-ID: <jhjimf67zs6.mognet@arm.com>
Date:   Thu, 02 Jul 2020 15:32:57 +0100
From:   Valentin Schneider <valentin.schneider@....com>
To:     Peter Zijlstra <peterz@...radead.org>
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 02/07/20 15:20, Peter Zijlstra wrote:
> 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.
>

Much better than homegrown stuff, thanks!

>> +		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
>>