[PATCH v2 2/2] x86/resctrl: Initialize a new resource group with default MBA values

[Xiaochen Shen]

Currently, when a new resource group is created, the allocation values
of the MBA resource are not initialized and remain meaningless data.

For example:

  mkdir /sys/fs/resctrl/p1
  cat /sys/fs/resctrl/p1/schemata
  MB:0=100;1=100

  echo "MB:0=10;1=20" > /sys/fs/resctrl/p1/schemata
  cat /sys/fs/resctrl/p1/schemata
  MB:0= 10;1= 20

  rmdir /sys/fs/resctrl/p1
  mkdir /sys/fs/resctrl/p2
  cat /sys/fs/resctrl/p2/schemata
  MB:0= 10;1= 20

Therefore, when the new group is created, it is reasonable to initialize
MBA resource with default values.

Initialize the MBA resource and cache resources in separate functions.

Signed-off-by: Xiaochen Shen <xiaochen.shen@xxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c |  4 +--
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 52 +++++++++++++++++++------------
 2 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 2dbd990..89320c0 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -342,10 +342,10 @@ int update_domains(struct rdt_resource *r, int closid)
 	if (cpumask_empty(cpu_mask) || mba_sc)
 		goto done;
 	cpu = get_cpu();
-	/* Update CBM on this cpu if it's in cpu_mask. */
+	/* Update resource control msr on this CPU if it's in cpu_mask. */
 	if (cpumask_test_cpu(cpu, cpu_mask))
 		rdt_ctrl_update(&msr_param);
-	/* Update CBM on other cpus. */
+	/* Update resource control msr on other CPUs. */
 	smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
 	put_cpu();
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 9cb6a1d..44b6dbf 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2581,8 +2581,8 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
 	return 0;
 }
 
-/**
- * rdtgroup_init_alloc - Initialize the new RDT group's allocations
+/*
+ * Initialize cache resources with default values.
  *
  * A new RDT group is being created on an allocation capable (CAT)
  * supporting system. Set this group up to start off with all usable
@@ -2591,33 +2591,45 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
  * If there are no more shareable bits available on any domain then
  * the entire allocation will fail.
  */
+static int rdtgroup_init_cat(struct rdt_resource *r, u32 closid)
+{
+	struct rdt_domain *d;
+	int ret;
+
+	list_for_each_entry(d, &r->domains, list) {
+		ret = __init_one_rdt_domain(d, r, closid);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* Initialize MBA resource with default values. */
+static void rdtgroup_init_mba(struct rdt_resource *r)
+{
+	struct rdt_domain *d;
+
+	list_for_each_entry(d, &r->domains, list) {
+		d->new_ctrl = is_mba_sc(r) ? MBA_MAX_MBPS : r->default_ctrl;
+		d->have_new_ctrl = true;
+	}
+}
+
+/* Initialize the RDT group's allocations. */
 static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
 {
 	struct rdt_resource *r;
-	struct rdt_domain *d;
 	int ret;
 
 	for_each_alloc_enabled_rdt_resource(r) {
-		/*
-		 * Only initialize default allocations for CBM cache
-		 * resources
-		 */
-		if (r->rid == RDT_RESOURCE_MBA)
-			continue;
-		list_for_each_entry(d, &r->domains, list) {
-			ret = __init_one_rdt_domain(d, r, rdtgrp->closid);
+		if (r->rid == RDT_RESOURCE_MBA) {
+			rdtgroup_init_mba(r);
+		} else {
+			ret = rdtgroup_init_cat(r, rdtgrp->closid);
 			if (ret < 0)
 				return ret;
 		}
-	}
-
-	for_each_alloc_enabled_rdt_resource(r) {
-		/*
-		 * Only initialize default allocations for CBM cache
-		 * resources
-		 */
-		if (r->rid == RDT_RESOURCE_MBA)
-			continue;
 		ret = update_domains(r, rdtgrp->closid);
 		if (ret < 0) {
 			rdt_last_cmd_puts("Failed to initialize allocations\n");
-- 
1.8.3.1