[PATCH v1 05/20] x86/resctrl: Create mba_sc configuration in the rdt_domain

[James Morse]

To support resctrl's MBA software controller, the architecture must provide
a second configuration array to hold the mbps_val from user-space.

This complicates the interface between the architecture code.

Make the filesystem parts of resctrl create an array for the mba_sc
values when the struct resctrl_schema is created. The software controller
can be changed to use this, allowing the architecture code to only
consider the values configured in hardware.

Signed-off-by: James Morse <james.morse@xxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/internal.h |  1 -
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 69 ++++++++++++++++++++++++++
 include/linux/resctrl.h                | 13 +++++
 3 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index e12b55f815bf..a7e2cbce29d5 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -36,7 +36,6 @@
 #define MBM_OVERFLOW_INTERVAL		1000
 #define MAX_MBA_BW			100u
 #define MBA_IS_LINEAR			0x4
-#define MBA_MAX_MBPS			U32_MAX
 #define MAX_MBA_BW_AMD			0x800
 #define MBM_CNTR_WIDTH_OFFSET_AMD	20
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index cf0db0b7a5d0..185f9bb992d1 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2030,6 +2030,60 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
 			     struct rdtgroup *prgrp,
 			     struct kernfs_node **mon_data_kn);
 
+static int mba_sc_domain_allocate(struct rdt_resource *res,
+				  struct rdt_domain *d)
+{
+	u32 num_closid = closid_free_map_len;
+	int cpu = cpumask_any(&d->cpu_mask);
+	int i;
+
+	d->mba_sc = kcalloc_node(num_closid, sizeof(*d->mba_sc),
+				 GFP_KERNEL, cpu_to_node(cpu));
+	if (!d->mba_sc)
+		return -ENOMEM;
+
+	for (i = 0; i < num_closid; i++)
+		d->mba_sc[i].mbps_val = MBA_MAX_MBPS;
+
+	return 0;
+}
+
+static int mba_sc_allocate(struct rdt_resource *r)
+{
+	struct rdt_domain *d;
+	int ret;
+
+	lockdep_assert_cpus_held();
+
+	if (!is_mba_sc(r))
+		return 0;
+
+	list_for_each_entry(d, &r->domains, list) {
+		ret = mba_sc_domain_allocate(r, d);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static void mba_sc_domain_destroy(struct rdt_resource *r,
+				  struct rdt_domain *d)
+{
+	kfree(d->mba_sc);
+	d->mba_sc = NULL;
+}
+
+static void mba_sc_destroy(struct rdt_resource *r)
+{
+	struct rdt_domain *d;
+
+	lockdep_assert_cpus_held();
+
+	list_for_each_entry(d, &r->domains, list)
+		mba_sc_domain_destroy(r, d);
+}
+
 static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 {
 	int ret = 0;
@@ -2117,17 +2171,27 @@ static int schemata_list_create(void)
 
 		if (ret)
 			break;
+
+		ret = mba_sc_allocate(r);
+		if (ret)
+			break;
 	}
 
 	return ret;
 }
 
+/*
+ * During rdt_kill_sb(), the mba_sc state is reset before
+ * destroy_schemata_list() is called: unconditionally try to free the
+ * array.
+ */
 static void schemata_list_destroy(void)
 {
 	struct resctrl_schema *s, *tmp;
 
 	list_for_each_entry_safe(s, tmp, &resctrl_schema_all, list) {
 		list_del(&s->list);
+		mba_sc_destroy(s->res);
 		kfree(s);
 	}
 }
@@ -3255,6 +3319,8 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d)
 		__check_limbo(d, true);
 		cancel_delayed_work(&d->cqm_limbo);
 	}
+	if (static_branch_unlikely(&rdt_enable_key) && is_mba_sc(r))
+		mba_sc_domain_destroy(r, d);
 	bitmap_free(d->rmid_busy_llc);
 	kfree(d->mbm_total);
 	kfree(d->mbm_local);
@@ -3287,6 +3353,9 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
 		}
 	}
 
+	if (is_mba_sc(r))
+		mba_sc_domain_allocate(r, d);
+
 	return 0;
 }
 
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 7aeeb4ac6bcc..3c8522d63261 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -15,6 +15,9 @@ int proc_resctrl_show(struct seq_file *m,
 
 #endif
 
+/* max value for struct resctrl_mba_sc's mbps_val */
+#define MBA_MAX_MBPS   U32_MAX
+
 /**
  * enum resctrl_conf_type - The type of configuration.
  * @CDP_NONE:	No prioritisation, both code and data are controlled or monitored.
@@ -39,6 +42,14 @@ struct resctrl_staged_config {
 	bool			have_new_ctrl;
 };
 
+/**
+ * struct resctrl_mba_sc - per-closid values for the control loop
+ * @mbps_val:		The user's specified control value
+ */
+struct resctrl_mba_sc {
+	u32		mbps_val;
+};
+
 /**
  * struct rdt_domain - group of CPUs sharing a resctrl resource
  * @list:		all instances of this resource
@@ -53,6 +64,7 @@ struct resctrl_staged_config {
  * @cqm_work_cpu:	worker CPU for CQM h/w counters
  * @plr:		pseudo-locked region (if any) associated with domain
  * @staged_config:	parsed configuration to be applied
+ * @mba_sc:	the mba software controller properties, indexed by closid
  */
 struct rdt_domain {
 	struct list_head		list;
@@ -67,6 +79,7 @@ struct rdt_domain {
 	int				cqm_work_cpu;
 	struct pseudo_lock_region	*plr;
 	struct resctrl_staged_config	staged_config[CDP_NUM_TYPES];
+	struct resctrl_mba_sc		*mba_sc;
 };
 
 /**
-- 
2.30.2