linux-kernel - Re: [RFC v2 PATCH 7/7] x86/resctrl: Add debug files when mounted with debug option

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Date:   Fri, 17 Feb 2023 11:49:45 -0600
From:   "Moger, Babu" <bmoger@....com>
To:     Fenghua Yu <fenghua.yu@...el.com>, Babu Moger <babu.moger@....com>,
        reinette.chatre@...el.com
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        corbet@....net, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, eranian@...gle.com,
        peternewman@...gle.com
Subject: Re: [RFC v2 PATCH 7/7] x86/resctrl: Add debug files when mounted with
 debug option

Hi Fenghua,

On 2/16/2023 7:50 PM, Fenghua Yu wrote:
> Hi, Babu,
>
> On 2/2/23 13:47, Babu Moger wrote:
>> Add the debug files to the resctrl hierarchy.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
>>   arch/x86/kernel/cpu/resctrl/rdtgroup.c |   27 
>> +++++++++++++++++++++++++++
>>   1 file changed, 27 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c 
>> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index c35d91b04de6..b7c72b011264 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -2398,6 +2398,31 @@ static int mkdir_mondata_all(struct 
>> kernfs_node *parent_kn,
>>                    struct rdtgroup *prgrp,
>>                    struct kernfs_node **mon_data_kn);
>>   +void resctrl_add_debug_file(struct kernfs_node *parent_kn,
>> +                const char *config, unsigned long fflags,
>> +                bool debug)
>> +{
>> +    struct rftype *rft;
>> +
>> +    rft = rdtgroup_get_rftype_by_name(config);
>> +    if (debug && rft) {
>> +        rft->fflags |= fflags;
>> +        rdtgroup_add_file(parent_kn, rft);
>> +    } else if (rft) {
>> +        rft->fflags &= ~fflags;
>> +        kernfs_remove_by_name(parent_kn, config);
>> +    }
>> +}
>> +
>> +static void resctrl_add_debug_files(bool debug)
>> +{
>> +    resctrl_add_debug_file(rdtgroup_default.kn, "rmid",
>> +                   RFTYPE_BASE, debug);
>> +    resctrl_add_debug_file(rdtgroup_default.kn, "closid",
>> +                   RFTYPE_BASE_CTRL, debug);
>> +    kernfs_activate(rdtgroup_default.kn);
>> +}
>> +
>>   static int rdt_enable_ctx(struct rdt_fs_context *ctx)
>>   {
>>       int ret = 0;
>> @@ -2411,6 +2436,8 @@ static int rdt_enable_ctx(struct rdt_fs_context 
>> *ctx)
>>       if (!ret && ctx->enable_mba_mbps)
>>           ret = set_mba_sc(true);
>>    > +    resctrl_add_debug_files(ctx->debug);
>
> It's better to change to:
> +    if (ctx->debug)
> +        resctrl_add_debug_files();
>
> Then the functions in the call chain can remove 'debug' parameter and 
> can be simpler.

Actually, debug parameter is required in the resctrl_add_debug_file to 
delete the file if it was mounted with debug option last time.

Thanks

Babu