linux-kernel - Re: [PATCH v16 18/34] fs/resctrl: Add the functionality to unassign MBM events

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Message-ID: <c1fa8b57-f655-4d64-bdf0-49e53325f367@amd.com>
Date: Thu, 7 Aug 2025 13:33:49 -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 18/34] fs/resctrl: Add the functionality to unassign
 MBM events

Hi Reinette,

On 7/30/25 14:53, Reinette Chatre wrote:
> Hi Babu,
> 
> On 7/25/25 11:29 AM, Babu Moger wrote:
>> The "mbm_event" counter assignment mode offers "num_mbm_cntrs" number of
>> counters that can be assigned to RMID, event pairs and monitor bandwidth
>> usage as long as it is assigned. If all the counters are in use, the
>> kernel logs the error message "Unable to allocate counter in domain" in
> 
> Needs an update to match new message.

Sure.

> 
>> /sys/fs/resctrl/info/last_cmd_status when a new assignment is requested.
>>
>> To make space for a new assignment, users must unassign an already
>> assigned counter and retry the assignment again.
>>
>> Add the functionality to unassign and free the counters in the domain.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
> 
> 
> ...
> 
> 
>> ---
>>  fs/resctrl/internal.h |  2 ++
>>  fs/resctrl/monitor.c  | 46 +++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 48 insertions(+)
>>
>> diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
>> index 419423bdabdc..216588842444 100644
>> --- a/fs/resctrl/internal.h
>> +++ b/fs/resctrl/internal.h
>> @@ -389,6 +389,8 @@ int resctrl_find_cleanest_closid(void);
>>  
>>  int rdtgroup_assign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
>>  			       struct mon_evt *mevt);
>> +void rdtgroup_unassign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
>> +				  struct mon_evt *mevt);
>>  
> 
> Similar comment as previous patch. Please try to keep all monitoring code in
> monitor.c. The caller rdtgroup_unassign_cntrs() can move to monitor.c and it
> can instead be made available via internal.h

Yes. Brought rdtgroup_unassign_cntrs() in this patch for completeness and
moved everything into monitor.c.
> 
> 
>>  #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
>>  int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
> 
> Reinette
> 
> 

-- 
Thanks
Babu Moger