linux-kernel - Re: [PATCH v8 08/10] fs/resctrl: Modify rdt_parse

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Message-ID: <601a28ca-143c-4821-8c78-9227a17012d5@amd.com>
Date: Tue, 26 Aug 2025 13:40:52 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
 tony.luck@...el.com, Dave.Martin@....com, james.morse@....com,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com
Cc: 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,
 thomas.lendacky@....com, pawan.kumar.gupta@...ux.intel.com,
 yosry.ahmed@...ux.dev, sohil.mehta@...el.com, xin@...or.com,
 kai.huang@...el.com, xiaoyao.li@...el.com, peterz@...radead.org,
 me@...aill.net, mario.limonciello@....com, xin3.li@...el.com,
 ebiggers@...gle.com, ak@...ux.intel.com, chang.seok.bae@...el.com,
 andrew.cooper3@...rix.com, perry.yuan@....com, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, manali.shukla@....com, gautham.shenoy@....com
Subject: Re: [PATCH v8 08/10] fs/resctrl: Modify rdt_parse_data to pass mode
 and CLOSID

Hi Reinette,

On 8/7/25 20:52, Reinette Chatre wrote:
> Hi Babu,
> 
> On 8/5/25 4:30 PM, Babu Moger wrote:
>> parse_cbm() and parse_bw() require mode and CLOSID to validate the Capacity
> 
> Again [1], parse_bw() does not validate any CBMs.

Removed parse_bw() reference.

> 
> To be more specific: "mode" -> "resource group mode"?

Sure.

> 
>> Bit Mask (CBM). It is passed via struct rdtgroup in struct rdt_parse_data.
>>
>> The io_alloc feature also uses CBMs to indicate which portions of cache are
>> allocated for I/O traffic. The CBMs are provided by user space and need to
>> be validated the same as CBMs provided for general (CPU) cache allocation.
>> parse_cbm() cannot be used as-is since io_alloc does not have rdtgroup
>> context.
>>
>> Pass the mode and CLOSID directly to parse_cbm() via struct rdt_parse_data
>> instead of through the rdtgroup struct to facilitate calling parse_cbm() to
>> verify the CBM of the io_alloc feature.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
> 
> ...
> 
>> @@ -156,9 +157,10 @@ static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
>>  static int parse_cbm(struct rdt_parse_data *data, struct resctrl_schema *s,
>>  		     struct rdt_ctrl_domain *d)
>>  {
>> -	struct rdtgroup *rdtgrp = data->rdtgrp;
>> +	enum rdtgrp_mode mode = data->mode;
>>  	struct resctrl_staged_config *cfg;
>>  	struct rdt_resource *r = s->res;
>> +	u32 closid = data->closid;
>>  	u32 cbm_val;
>>  
>>  	cfg = &d->staged_config[s->conf_type];
>> @@ -171,7 +173,7 @@ static int parse_cbm(struct rdt_parse_data *data, struct resctrl_schema *s,
>>  	 * Cannot set up more than one pseudo-locked region in a cache
>>  	 * hierarchy.
>>  	 */
>> -	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
>> +	if (mode == RDT_MODE_PSEUDO_LOCKSETUP &&
>>  	    rdtgroup_pseudo_locked_in_hierarchy(d)) {
>>  		rdt_last_cmd_puts("Pseudo-locked region in hierarchy\n");
>>  		return -EINVAL;
>> @@ -180,8 +182,8 @@ static int parse_cbm(struct rdt_parse_data *data, struct resctrl_schema *s,
>>  	if (!cbm_validate(data->buf, &cbm_val, r))
>>  		return -EINVAL;
>>  
>> -	if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
>> -	     rdtgrp->mode == RDT_MODE_SHAREABLE) &&
>> +	if ((mode == RDT_MODE_EXCLUSIVE ||
>> +	     mode == RDT_MODE_SHAREABLE) &&
> 
> This can now be on one line?

Sure.

> 
>>  	    rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
>>  		rdt_last_cmd_puts("CBM overlaps with pseudo-locked region\n");
>>  		return -EINVAL;
> 
> Reinette
> 
> [1] https://lore.kernel.org/lkml/798ba4db-3ac2-44a9-9e0d-e9cbb0dbff45@intel.com/
> 

-- 
Thanks
Babu Moger