linux-kernel - Re: [PATCH v7 10/24] x86/resctrl: Introduce mbm_total_cfg and mbm_local_cfg in struct rdt_hw_mon

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Message-ID: <87092f53-173d-480e-8e5d-de55a04d640d@amd.com>
Date: Mon, 23 Sep 2024 13:43:26 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
 fenghua.yu@...el.com, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com
Cc: x86@...nel.org, hpa@...or.com, paulmck@...nel.org, rdunlap@...radead.org,
 tj@...nel.org, peterz@...radead.org, yanjiewtw@...il.com,
 kim.phillips@....com, lukas.bulwahn@...il.com, seanjc@...gle.com,
 jmattson@...gle.com, leitao@...ian.org, jpoimboe@...nel.org,
 rick.p.edgecombe@...el.com, kirill.shutemov@...ux.intel.com,
 jithu.joseph@...el.com, kai.huang@...el.com, kan.liang@...ux.intel.com,
 daniel.sneddon@...ux.intel.com, pbonzini@...hat.com, sandipan.das@....com,
 ilpo.jarvinen@...ux.intel.com, peternewman@...gle.com,
 maciej.wieczor-retman@...el.com, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, eranian@...gle.com, james.morse@....com
Subject: Re: [PATCH v7 10/24] x86/resctrl: Introduce mbm_total_cfg and
 mbm_local_cfg in struct rdt_hw_mon_domain

Hi Reinette,

On 9/19/24 11:51, Reinette Chatre wrote:
> Hi Babu,
> 
> On 9/4/24 3:21 PM, Babu Moger wrote:
>> If the BMEC (Bandwidth Monitoring Event Configuration) feature is
>> supported, the bandwidth events can be configured to track specific
>> events. The event configuration is domain specific. ABMC (Assignable
>> Bandwidth Monitoring Counters) feature needs event configuration
>> information to assign hardware counter to an RMID. Event configurations
> 
> "to assign hardware counter" -> "to assign a hardware counter"?

Sure.

> 
>> are not stored in resctrl but instead always read from or written to
>> hardware directly when prompted by user space.
>>
>> Read the event configuration from the hardware during the domain
>> initialization. Save the configuration value in rdt_hw_mon_domain,
> 
> "rdt_hw_mon_domain" -> "struct rdt_hw_mon_domain"

Sure.

> 
>> so it can be used for counter assignment.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
>> v7: Fixed initializing INVALID_CONFIG_VALUE to mbm_local_cfg in case of error.
>>
>> v6: Renamed resctrl_arch_mbm_evt_config -> resctrl_mbm_evt_config_init
>>     Initialized value to INVALID_CONFIG_VALUE if it is not configurable.
>>     Minor commit message update.
>>
>> v5: Exported mon_event_config_index_get.
>>     Renamed arch_domain_mbm_evt_config to resctrl_arch_mbm_evt_config.
>>
>> v4: Read the configuration information from the hardware to initialize.
>>     Added few commit messages.
>>     Fixed the tab spaces.
>>
>> v3: Minor changes related to rebase in mbm_config_write_domain.
>>
>> v2: No changes.
>> ---
>>  arch/x86/kernel/cpu/resctrl/core.c     |  2 ++
>>  arch/x86/kernel/cpu/resctrl/internal.h |  9 +++++++++
>>  arch/x86/kernel/cpu/resctrl/monitor.c  | 26 ++++++++++++++++++++++++++
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |  4 +---
>>  4 files changed, 38 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 00ad00258df2..2a4be004a2df 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -632,6 +632,8 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
>>  
>>  	arch_mon_domain_online(r, d);
>>  
>> +	resctrl_mbm_evt_config_init(hw_dom);
> 
> Now that the arch and fs separate becomes clear I wonder if it may help to understand
> this work if we start using clear namespaces to help this distinction. Surely the
> arch code is very inconsistent in this regard (thus this function fits in), but
> resctrl_ has to be the prefix for fs code.
> 

Will rename the function to arch_mbm_evt_config_init().
-- 
Thanks
Babu Moger