[RFC PATCH 22/31] fs/resctrl: Add region-based control names and resctrl_ctrl_name_region()

[Chen Yu]

ERDT exposes per-memory-region bandwidth allocation controls, where each
region has an optimal (OPT), minimum (MIN) and maximum (MAX) control.

Extend enum resctrl_ctrl_name with the REGION<n>_{OPT,MIN,MAX} names (and
their string forms). These enumerators are only assigned to a control when
arch code adds a region control to rdt_resource::controls, which happens
only when the hardware supports ERDT (erdt_cpu_has()); on other platforms
they are simply unused.

Add resctrl_ctrl_name_region() so that the architecture code can retrieve
the control name for a given region and control type when creating the
corresponding controllers.

Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
---
 fs/resctrl/ctrlmondata.c | 12 ++++++++++++
 include/linux/resctrl.h  | 29 ++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 74fa1215e8b2..d65036f7079e 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -304,6 +304,18 @@ static const char * const resctrl_ctrl_name[] = {
 	[RESCTRL_CTRL_NAME_DEF]		= "",
 	[RESCTRL_CTRL_NAME_MIN]		= "MIN",
 	[RESCTRL_CTRL_NAME_MAX]		= "MAX",
+	[RESCTRL_CTRL_NAME_REGION0_OPT]	= "REGION0_OPT",
+	[RESCTRL_CTRL_NAME_REGION0_MIN]	= "REGION0_MIN",
+	[RESCTRL_CTRL_NAME_REGION0_MAX]	= "REGION0_MAX",
+	[RESCTRL_CTRL_NAME_REGION1_OPT]	= "REGION1_OPT",
+	[RESCTRL_CTRL_NAME_REGION1_MIN]	= "REGION1_MIN",
+	[RESCTRL_CTRL_NAME_REGION1_MAX]	= "REGION1_MAX",
+	[RESCTRL_CTRL_NAME_REGION2_OPT]	= "REGION2_OPT",
+	[RESCTRL_CTRL_NAME_REGION2_MIN]	= "REGION2_MIN",
+	[RESCTRL_CTRL_NAME_REGION2_MAX]	= "REGION2_MAX",
+	[RESCTRL_CTRL_NAME_REGION3_OPT]	= "REGION3_OPT",
+	[RESCTRL_CTRL_NAME_REGION3_MIN]	= "REGION3_MIN",
+	[RESCTRL_CTRL_NAME_REGION3_MAX]	= "REGION3_MAX",
 };
 
 const char *resctrl_ctrl_name_str(enum resctrl_ctrl_name name)
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 7bbda28baccf..3969db01f4cc 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -348,14 +348,41 @@ struct resctrl_mon {
  *				has the same name as the resource.
  * @RESCTRL_CTRL_NAME_MIN:	"MIN"
  * @RESCTRL_CTRL_NAME_MAX:	"MAX"
+ *
+ * The REGION* names describe the region based bandwidth allocation controls of
+ * each memory region has an optimal (OPT), minimum (MIN) andcmaximum (MAX) control.
+ * They are only ever assigned to a control when arch code adds a region control
+ * to rdt_resource::controls, which happens only when the hardware supports ERDT
+ * (erdt_cpu_has()); on other platforms these enumerators are simply unused.
  */
 enum resctrl_ctrl_name {
 	RESCTRL_CTRL_NAME_DEF,
 	RESCTRL_CTRL_NAME_MIN,
 	RESCTRL_CTRL_NAME_MAX,
-	RESCTRL_CTRL_NAME_LAST = RESCTRL_CTRL_NAME_MAX
+	RESCTRL_CTRL_NAME_REGION0_OPT,
+	RESCTRL_CTRL_NAME_REGION0_MIN,
+	RESCTRL_CTRL_NAME_REGION0_MAX,
+	RESCTRL_CTRL_NAME_REGION1_OPT,
+	RESCTRL_CTRL_NAME_REGION1_MIN,
+	RESCTRL_CTRL_NAME_REGION1_MAX,
+	RESCTRL_CTRL_NAME_REGION2_OPT,
+	RESCTRL_CTRL_NAME_REGION2_MIN,
+	RESCTRL_CTRL_NAME_REGION2_MAX,
+	RESCTRL_CTRL_NAME_REGION3_OPT,
+	RESCTRL_CTRL_NAME_REGION3_MIN,
+	RESCTRL_CTRL_NAME_REGION3_MAX,
+	RESCTRL_CTRL_NAME_LAST = RESCTRL_CTRL_NAME_REGION3_MAX
 };
 
+#define RESCTRL_CTRL_REGION_NR_CTRLS	3
+
+static inline enum resctrl_ctrl_name
+resctrl_ctrl_name_region(unsigned int region, unsigned int type)
+{
+	return RESCTRL_CTRL_NAME_REGION0_OPT +
+	       region * RESCTRL_CTRL_REGION_NR_CTRLS + type;
+}
+
 /* Flags for rdt_resource::flags and resctrl_ctrl::flags */
 #define RESCTRL_CTRL_FLAG_LINEAR		BIT(0)
 #define RESCTRL_CTRL_FLAG_SPARSE_BITMASKS	BIT(1)
-- 
2.43.0