Re: RE: [PATCH v8 4/8] x86/resctrl: Add comments on RFTYPE flags hierarchy

[Moger, Babu]

Hi Shaopeng,

On 8/23/23 02:03, Shaopeng Tan (Fujitsu) wrote:
> Hi Babu,
> 
> 
>> resctrl uses RFTYPE flags for creating resctrl directory structure.
>>
>> Definitions and directory structures are not documented. Add comments to
>> improve the readability and help future additions.
>>
>> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
>> ---
>>  arch/x86/kernel/cpu/resctrl/internal.h | 58
>> ++++++++++++++++++++++++++
>>  1 file changed, 58 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h
>> b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 2051179a3b91..b09e7abd1299 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -240,6 +240,64 @@ struct rdtgroup {
>>
>>  /*
>>   * Define the file type flags for base and info directories.
>> + *
>> + * RESCTRL filesystem has two main components
>> + *	a. info
>> + *	b. base
>> + *
>> + * /sys/fs/resctrl/
>> + *	|
>> + *	--> info (Top level directory named "info". Contains files that
>> + *	|	  provide details on control and monitoring resources.)
>> + *	|
>> + *	--> base (Root directory associated with default resource group
>> + *		  as well as directories created by user for MON and CTRL
>> + *		  groups. Contains files to interact with MON and CTRL
>> + *		  groups.)
>> + *
>> + *	Note: resctrl uses flags for files, not for directories.
>> + *	      Directories are created based on the resource type. Added
>> + *	      directories below for better understanding.
>> + *
>> + *	info directory structure
>> + *	------------------------------------------------------------------
>> + *	--> RFTYPE_INFO
>> + *	    directory: info
> "directory" ->"Directory"

Sorry.. I missed that. Will fix.

> 
>> + *		--> RFTYPE_TOP (Files in top level of info directory)
>> + *		    File: last_cmd_status
>> + *
>> + *		--> RFTYPE_MON (Files for all monitoring resources)
>> + *		    Directory: L3_MON
>> + *		        Files: mon_features, num_rmids
>> + *
>> + *			--> RFTYPE_RES_CACHE (Files for cache monitoring
>> resources)
>> + *			    Directory: L3_MON
>> + *			        Files: max_threshold_occupancy,
>> + *			               mbm_total_bytes_config,
>> + *			               mbm_local_bytes_config
>> + *
>> + *		--> RFTYPE_CTRL (Files for all control resources)
>> + *		    Directories: L2, L3, MB, SMBA
>> + *		           File: num_closids
>> + *
>> + *			--> RFTYPE_RES_CACHE (Files for cache control
>> resources)
>> + *			    Directories: L2, L3
>> + *			          Files: bit_usage, cbm_mask,
>> min_cbm_bits,
>> + *			                 shareable_bits
>> + *
>> + *			--> RFTYPE_RES_MB (Files for memory control
>> resources)
>> + *			    Directories: MB, SMBA
>> + *			          Files: bandwidth_gran, delay_linear,
>> + *			                 min_bandwidth,
>> thread_throttle_mode
>> + *
>> + *	base directory structure
>> + *	------------------------------------------------------------------
>> + *	--> RFTYPE_BASE (Files common for both MON and CTRL groups)
>> + *	    Files: cpus, cpus_list, tasks
>> + *
>> + *		--> RFTYPE_CTRL (Files only for CTRL group)
>> + *		    Files: mode, schemata, size
> I think this is reinette's advice,
> but "		--> RFTYPE_CTRL (Files only for CTRL group)" looks like a subdirectory.
> Is this expected?

Yes. It is expected. We have two combinations here.
1. RFTYPE_BASE
2. RFTYPE_BASE | RFTYPE_CTRL

Because it is OR'd with two flags, I would say it is displayed as expected.

Thanks
Babu Moger