linux-kernel - Re: [PATCH v15 26/34] fs/resctrl: Add event configuration directory under info/L3

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Message-ID: <7ecd5229-9966-4983-b053-09c8bc560aa8@amd.com>
Date: Tue, 22 Jul 2025 15:11:59 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
 tony.luck@...el.com, james.morse@....com, tglx@...utronix.de,
 mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com
Cc: Dave.Martin@....com, x86@...nel.org, hpa@...or.com,
 akpm@...ux-foundation.org, paulmck@...nel.org, rostedt@...dmis.org,
 Neeraj.Upadhyay@....com, david@...hat.com, arnd@...db.de, fvdl@...gle.com,
 seanjc@...gle.com, jpoimboe@...nel.org, pawan.kumar.gupta@...ux.intel.com,
 xin@...or.com, manali.shukla@....com, tao1.su@...ux.intel.com,
 sohil.mehta@...el.com, kai.huang@...el.com, xiaoyao.li@...el.com,
 peterz@...radead.org, xin3.li@...el.com, kan.liang@...ux.intel.com,
 mario.limonciello@....com, thomas.lendacky@....com, perry.yuan@....com,
 gautham.shenoy@....com, chang.seok.bae@...el.com, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, peternewman@...gle.com, eranian@...gle.com
Subject: Re: [PATCH v15 26/34] fs/resctrl: Add event configuration directory
 under info/L3_MON/

Hi Reinette,

On 7/17/25 22:54, Reinette Chatre wrote:
> Hi Babu,
> 
> On 7/8/25 3:17 PM, Babu Moger wrote:
>> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
>> index 15d10c346307..bb28ef7e4600 100644
>> --- a/fs/resctrl/rdtgroup.c
>> +++ b/fs/resctrl/rdtgroup.c
>> @@ -86,6 +86,8 @@ enum resctrl_event_id mba_mbps_default_event;
>>  
>>  static bool resctrl_debug;
>>  
>> +extern struct mbm_transaction mbm_transactions[NUM_MBM_TRANSACTIONS];
>> +
> 
> Please move this extern to fs/resctrl/internal.h.

No required anymore as event_filter_show() is moved to monitor.c

> 
>>  void rdt_last_cmd_clear(void)
>>  {
>>  	lockdep_assert_held(&rdtgroup_mutex);
>> @@ -1895,6 +1897,25 @@ static int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of,
>>  	return ret;
>>  }
>>  
>> +static int event_filter_show(struct kernfs_open_file *of, struct seq_file *seq, void *v)
>> +{
>> +	struct mon_evt *mevt = rdt_kn_parent_priv(of->kn);
>> +	bool sep = false;
>> +	int i;
>> +
>> +	for (i = 0; i < NUM_MBM_TRANSACTIONS; i++) {
>> +		if (mevt->evt_cfg & mbm_transactions[i].val) {
> 
> mevt->evt_cfg could possibly be changed concurrently. This should
> be protected with the rdtgroup_mutex.

Sure.

> 
>> +			if (sep)
>> +				seq_putc(seq, ',');
>> +			seq_printf(seq, "%s", mbm_transactions[i].name);
>> +			sep = true;
>> +		}
>> +	}
>> +	seq_putc(seq, '\n');
>> +
>> +	return 0;
>> +}
>> +
>>  /* rdtgroup information files for one cache resource. */
>>  static struct rftype res_common_files[] = {
>>  	{
>> @@ -2019,6 +2040,12 @@ static struct rftype res_common_files[] = {
>>  		.seq_show	= mbm_local_bytes_config_show,
>>  		.write		= mbm_local_bytes_config_write,
>>  	},
>> +	{
>> +		.name		= "event_filter",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= event_filter_show,
>> +	},
>>  	{
>>  		.name		= "mbm_assign_mode",
>>  		.mode		= 0444,
>> @@ -2279,10 +2306,48 @@ int rdtgroup_kn_mode_restore(struct rdtgroup *r, const char *name,
>>  	return ret;
>>  }
>>  
>> +static int resctrl_mkdir_event_configs(struct rdt_resource *r, struct kernfs_node *l3_mon_kn)
>> +{
>> +	struct kernfs_node *kn_subdir, *kn_subdir2;
>> +	struct mon_evt *mevt;
>> +	int ret;
>> +
>> +	kn_subdir = kernfs_create_dir(l3_mon_kn, "event_configs", l3_mon_kn->mode, NULL);
>> +	if (IS_ERR(kn_subdir))
>> +		return PTR_ERR(kn_subdir);
>> +
>> +	ret = rdtgroup_kn_set_ugid(kn_subdir);
>> +	if (ret)
>> +		return ret;
>> +
>> +	for_each_mon_event(mevt) {
>> +		if (mevt->rid != r->rid || !mevt->enabled || !resctrl_is_mbm_event(mevt->evtid))
>> +			continue;
>> +
>> +		kn_subdir2 = kernfs_create_dir(kn_subdir, mevt->name, kn_subdir->mode, mevt);
>> +		if (IS_ERR(kn_subdir2)) {
>> +			ret = PTR_ERR(kn_subdir2);
>> +			goto out_config;
>> +		}
>> +
>> +		ret = rdtgroup_kn_set_ugid(kn_subdir2);
>> +		if (ret)
>> +			goto out_config;
>> +
>> +		ret = rdtgroup_add_files(kn_subdir2, RFTYPE_ASSIGN_CONFIG);
>> +		if (ret)
>> +			break;
>> +	}
>> +
>> +out_config:
>> +	return ret;
> 
> No "config" is happening here so the goto label can just be "out".
> 

Sure.

>> +}
>> +
>>  static int rdtgroup_mkdir_info_resdir(void *priv, char *name,
>>  				      unsigned long fflags)
>>  {
>>  	struct kernfs_node *kn_subdir;
>> +	struct rdt_resource *r;
>>  	int ret;
>>  
>>  	kn_subdir = kernfs_create_dir(kn_info, name,
>   
> 
> Reinette
> 

-- 
Thanks
Babu Moger