[PATCH v6 4/8] x86/resctrl: Add comments on RFTYPE flags hierarchy

Babu Moger
2023-07-19T23:22:18Z

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@amd.com>
---
arch/x86/kernel/cpu/resctrl/internal.h | 48 ++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 2051179a3b91..783c3e36633c 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -240,6 +240,54 @@ 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.)
+ *
+ * info directory structure
+ * ------------------------------------------------------------------
+ * --> RFTYPE_INFO
+ * --> <info> directory
+ * --> RFTYPE_TOP_INFO
+ * Files: last_cmd_status
+ *
+ * --> RFTYPE_MON_INFO
+ * --> <L3_MON> directory
+ * Files: max_threshold_occupancy, mon_features,
+ * num_rmids, mbm_total_bytes_config,
+ * mbm_locat_bytes_config
+ *
+ * --> RFTYPE_CTRL_INFO
+ * --> RFTYPE_RES_CACHE
+ * --> <L2,L3> directory
+ * Files: bit_usage, cbm_mask, min_cbm_bits,
+ * num_closids, shareable_bits
+ *
+ * --> RFTYPE_RES_MB
+ * --> <MB,SMBA> directory
+ * Files: bandwidth_gran, delay_linear,
+ * min_bandwidth, num_closids,
+ * thread_throttle_mode
+ *
+ * base (root) directory structure
+ * ------------------------------------------------------------------
+ * --> RFTYPE_BASE (Files common for both MON and CTRL groups)
+ * Files: cpus, cpus_list, tasks
+ *
+ * --> RFTYPE_CTRL_BASE (Files only for CTRL group)
+ * Files: mode, schemata, size
+ *
*/
#define RFTYPE_INFO BIT(0)
#define RFTYPE_BASE BIT(1)