[PATCH v13 04/10] x86/resctrl: Add comments on RFTYPE flags hierarchy

[Babu Moger]

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>
---
v13: Fixed the format issues in the documentation. Needed few minor format
     changes to address the syntax issues.(Reinette)
     Removed "Reviewed-by and Tested-by" flags as the patch has changed.

v12: Moved the comments from arch/x86/kernel/cpu/resctrl/internal.h
     to Documentation/arch/x86/resctrl.rst. (Boris)
---
 Documentation/arch/x86/resctrl.rst | 64 ++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 178ab1d8f747..1163da74f734 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -369,6 +369,70 @@ When monitoring is enabled all MON groups will also contain:
 	the sum for all tasks in the CTRL_MON group and all tasks in
 	MON groups. Please see example section for more details on usage.
 
+RESCTRL filesystem implementation notes
+=======================================
+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. The RFTYPE flags
+	      are defined in arch/x86/kernel/cpu/resctrl/internal.h.
+
+	info directory structure
+
+	-> RFTYPE_INFO
+	   Directory: info
+
+	-> 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, L2CODE, L2DATA, L3CODE, L3DATA
+	          File: num_closids
+
+		-> RFTYPE_RES_CACHE (Files for cache control resources)
+		   Directories: L2, L3, L2CODE, L2DATA, L3CODE, L3DATA
+		         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 for CTRL group)
+		   Files: mode, schemata, size
+
 Resource allocation rules
 -------------------------
 
-- 
2.34.1