Re: [PATCH v8 8/8] x86/resctrl: Display hardware ids of resource groups

[Moger, Babu]

Hi Reinette,

On 8/29/23 15:14, Reinette Chatre wrote:
> Hi Babu,
> 
> On 8/21/2023 4:30 PM, Babu Moger wrote:
> 
> ...
> 
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 2fae6d9e24d3..3fa32c1c2677 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -296,9 +296,15 @@ struct rdtgroup {
>>   *	--> RFTYPE_BASE (Files common for both MON and CTRL groups)
>>   *	    Files: cpus, cpus_list, tasks
>>   *
>> + *		--> RFTYPE_DEBUG (Files to help resctrl debugging)
>> + *		    File: mon_hw_id
>> + *
> 
> This does not look right. I think mon_hw_id should have RFTYPE_MON
> (more below).

I am not sure about this (more below).

> 
>>   *		--> RFTYPE_CTRL (Files only for CTRL group)
>>   *		    Files: mode, schemata, size
>>   *
>> + *			--> RFTYPE_DEBUG (Files to help resctrl debugging)
>> + *			    File: ctrl_hw_id
>> + *
>>   */
>>  #define RFTYPE_INFO			BIT(0)
>>  #define RFTYPE_BASE			BIT(1)
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 94bd69f9964c..e0c2479acf49 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -776,6 +776,38 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
>>  	return ret;
>>  }
>>  
>> +static int rdtgroup_closid_show(struct kernfs_open_file *of,
>> +				struct seq_file *s, void *v)
>> +{
>> +	struct rdtgroup *rdtgrp;
>> +	int ret = 0;
>> +
>> +	rdtgrp = rdtgroup_kn_lock_live(of->kn);
>> +	if (rdtgrp)
>> +		seq_printf(s, "%u\n", rdtgrp->closid);
>> +	else
>> +		ret = -ENOENT;
>> +	rdtgroup_kn_unlock(of->kn);
>> +
>> +	return ret;
>> +}
>> +
>> +static int rdtgroup_rmid_show(struct kernfs_open_file *of,
>> +			      struct seq_file *s, void *v)
>> +{
>> +	struct rdtgroup *rdtgrp;
>> +	int ret = 0;
>> +
>> +	rdtgrp = rdtgroup_kn_lock_live(of->kn);
>> +	if (rdtgrp)
>> +		seq_printf(s, "%u\n", rdtgrp->mon.rmid);
>> +	else
>> +		ret = -ENOENT;
>> +	rdtgroup_kn_unlock(of->kn);
>> +
>> +	return ret;
>> +}
>> +
>>  #ifdef CONFIG_PROC_CPU_RESCTRL
>>  
>>  /*
>> @@ -1837,6 +1869,13 @@ static struct rftype res_common_files[] = {
>>  		.seq_show	= rdtgroup_tasks_show,
>>  		.fflags		= RFTYPE_BASE,
>>  	},
>> +	{
>> +		.name		= "mon_hw_id",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= rdtgroup_rmid_show,
>> +		.fflags		= RFTYPE_BASE | RFTYPE_DEBUG,
> 
> I missed this earlier but I think this also needs a RFTYPE_MON.
> Perhaps patch 3 can introduce a new RFTYPE_MON_BASE to not
> have the flags of the two new files look too different?

We have two types of files in base directory structure.

 if (rtype == RDTCTRL_GROUP)
                files = RFTYPE_BASE | RFTYPE_CTRL;
        else
                files = RFTYPE_BASE | RFTYPE_MON;

1. RFTYPE_BASE | RFTYPE_CTRL;
   Files for the control group only.

2. RFTYPE_BASE | RFTYPE_MON;
   Files for both control and mon groups. However, RFTYPE_MON is not used
for any files. It is only RFTYPE_BASE.

Because of the check in rdtgroup_add_files it all works fine.
For the control group it creates files with RFTYPE_BASE | RFTYPE_CTRL and
RFTYPE_BASE.

For the mon group it creates files with RFTYPE_BASE only.

Adding FTYPE_MON_BASE will be a problem.

-- 
Thanks
Babu Moger