linux-kernel - Re: [PATCH v16 13/34] fs/resctrl: Introduce interface to display number of free MBM counters

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Message-ID: <05075026-38b6-408e-bbe3-15572827365d@amd.com>
Date: Wed, 6 Aug 2025 17:04:44 -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 v16 13/34] fs/resctrl: Introduce interface to display
 number of free MBM counters

Hi Reinette,

On 8/6/25 16:31, Reinette Chatre wrote:
> Hi Babu,
> 
> On 8/6/25 2:19 PM, Moger, Babu wrote:
>>> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
>>> index a09566720d4f..15d10c346307 100644
>>> --- a/fs/resctrl/rdtgroup.c
>>> +++ b/fs/resctrl/rdtgroup.c
>>> @@ -1853,6 +1853,48 @@ static int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of,
>>>  	return 0;
>>>  }
>>>  
>>> +static int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of,
>>> +					    struct seq_file *s, void *v)
>>> +{
>>> +	struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
>>> +	struct rdt_mon_domain *dom;
>>> +	bool sep = false;
>>> +	u32 cntrs, i;
>>> +	int ret = 0;
>>> +
>>> +	cpus_read_lock();
>>> +	mutex_lock(&rdtgroup_mutex);
>>> +
>>> +	rdt_last_cmd_clear();
>>> +
>>> +	if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
>>> +		rdt_last_cmd_puts("mbm_event mode is not enabled\n");
>>> +		ret = -EINVAL;
>>> +		goto out_unlock;
>>> +	}
>>> +
>>> +	list_for_each_entry(dom, &r->mon_domains, hdr.list) {
>>> +		if (sep)
>>> +			seq_putc(s, ';');
>>> +
>>> +		cntrs = 0;
>>> +		for (i = 0; i < r->mon.num_mbm_cntrs; i++) {
>>> +			if (!dom->cntr_cfg[i].rdtgrp)
>>> +				cntrs++;
>>> +		}
>>> +
>>> +		seq_printf(s, "%d=%u", dom->hdr.id, cntrs);
>>> +		sep = true;
>>> +	}
>>> +	seq_putc(s, '\n');
>>> +
>>> +out_unlock:
>>> +	mutex_unlock(&rdtgroup_mutex);
>>> +	cpus_read_unlock();
>>> +
>>> +	return ret;
>>> +}
>>> +
>>
>> This also can be moved to monitor.c.  What do you think?
> 
> Yes, I believe monitor.c is most appropriate for all the monitoring
> related handlers [1].

Sure. Will do.

> 
> Reinette
> 
> [1] https://lore.kernel.org/lkml/0fa9a12b-e900-4ceb-b59c-e653ec3db0ca@intel.com/
> 

-- 
Thanks
Babu Moger