[PATCH 18/21] x86/intel_rdt/cqm: Add hotcpu support

[Vikas Shivappa]

Resource groups have a per domain directory under "mon_data". Add or
remove these directories as and when domains come online and go offline.
Also update the per cpu rmids and cache upon onlining and offlining
cpus.

Signed-off-by: Vikas Shivappa <vikas.shivappa@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/intel_rdt.c          | 28 +++++++++++++++-----
 arch/x86/kernel/cpu/intel_rdt.h          |  9 +++++++
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 44 ++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 63bfb47c..8c7643d 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -438,6 +438,13 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
 
 	cpumask_set_cpu(cpu, &d->cpu_mask);
 	list_add_tail(&d->list, add_pos);
+
+	/*
+	 * If resctrl is mounted, add
+	 * per domain monitor data directories.
+	 */
+	if (static_branch_unlikely(&rdt_mon_enable_key))
+		mkdir_mondata_subdir_allrdtgrp(r, d->id);
 }
 
 static void domain_remove_cpu(int cpu, struct rdt_resource *r)
@@ -453,19 +460,28 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 
 	cpumask_clear_cpu(cpu, &d->cpu_mask);
 	if (cpumask_empty(&d->cpu_mask)) {
+		/*
+		 * If resctrl is mounted, remove all the
+		 * per domain monitor data directories.
+		 */
+		if (static_branch_unlikely(&rdt_mon_enable_key))
+			rmdir_mondata_subdir_allrdtgrp(r, d->id);
 		kfree(d->ctrl_val);
 		list_del(&d->list);
 		kfree(d);
 	}
 }
 
-static void clear_closid(int cpu)
+static void clear_closid_rmid(int cpu)
 {
 	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
 
 	per_cpu(cpu_closid, cpu) = 0;
+	per_cpu(cpu_rmid, cpu) = 0;
+
 	state->closid = 0;
-	wrmsr(IA32_PQR_ASSOC, state->rmid, 0);
+	state->rmid = 0;
+	wrmsr(IA32_PQR_ASSOC, 0, 0);
 }
 
 static int intel_rdt_online_cpu(unsigned int cpu)
@@ -473,11 +489,11 @@ static int intel_rdt_online_cpu(unsigned int cpu)
 	struct rdt_resource *r;
 
 	mutex_lock(&rdtgroup_mutex);
-	for_each_alloc_capable_rdt_resource(r)
+	for_each_capable_rdt_resource(r)
 		domain_add_cpu(cpu, r);
 	/* The cpu is set in default rdtgroup after online. */
 	cpumask_set_cpu(cpu, &rdtgroup_default.cpu_mask);
-	clear_closid(cpu);
+	clear_closid_rmid(cpu);
 	mutex_unlock(&rdtgroup_mutex);
 
 	return 0;
@@ -500,7 +516,7 @@ static int intel_rdt_offline_cpu(unsigned int cpu)
 	struct rdt_resource *r;
 
 	mutex_lock(&rdtgroup_mutex);
-	for_each_alloc_capable_rdt_resource(r)
+	for_each_capable_rdt_resource(r)
 		domain_remove_cpu(cpu, r);
 	list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
 		if (cpumask_test_and_clear_cpu(cpu, &rdtgrp->cpu_mask)) {
@@ -508,7 +524,7 @@ static int intel_rdt_offline_cpu(unsigned int cpu)
 			break;
 		}
 	}
-	clear_closid(cpu);
+	clear_closid_rmid(cpu);
 	mutex_unlock(&rdtgroup_mutex);
 
 	return 0;
diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index ea7a86f..b771dae 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -290,6 +290,11 @@ enum {
 	RDT_NUM_RESOURCES,
 };
 
+#define for_each_capable_rdt_resource(r)				      \
+	for (r = rdt_resources_all; r < rdt_resources_all + RDT_NUM_RESOURCES;\
+	     r++)							      \
+		if (r->alloc_capable || r->mon_capable)
+
 #define for_each_alloc_capable_rdt_resource(r)				      \
 	for (r = rdt_resources_all; r < rdt_resources_all + RDT_NUM_RESOURCES;\
 	     r++)							      \
@@ -350,5 +355,9 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of,
 void rdt_get_mon_l3_config(struct rdt_resource *r);
 void mon_event_count(void *info);
 int rdtgroup_mondata_show(struct seq_file *m, void *arg);
+void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
+				    unsigned int dom_id);
+void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
+				    unsigned int dom_id);
 
 #endif /* _ASM_X86_INTEL_RDT_H */
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 2384c07..8e1581a 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1348,6 +1348,27 @@ static int mon_addfile(struct kernfs_node *parent_kn, const char *name,
 	return ret;
 }
 
+/*
+ * Remove all subdirectories of mon_data of ctrl_mon groups
+ * and monitor groups with given domain id.
+ */
+void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int dom_id)
+{
+	struct rdtgroup *pr, *cr;
+	char name[32];
+
+	if (!r->mon_enabled)
+		return;
+
+	list_for_each_entry(pr, &rdt_all_groups, rdtgroup_list) {
+		sprintf(name, "mon_%s_%02d", r->name, dom_id);
+		kernfs_remove_by_name(pr->mon_data_kn, name);
+
+		list_for_each_entry(cr, &pr->crdtgrp_list, crdtgrp_list)
+			kernfs_remove_by_name(cr->mon_data_kn, name);
+	}
+}
+
 static int get_rdt_resourceid(struct rdt_resource *r)
 {
 	if (r > (rdt_resources_all + RDT_NUM_RESOURCES - 1) ||
@@ -1407,6 +1428,29 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, int domid,
 	return ret;
 }
 
+/*
+ * Add all subdirectories of mon_data for "ctrl_mon" groups
+ * and "monitor" groups with given domain id.
+ */
+void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int domid)
+{
+	struct kernfs_node *parent_kn;
+	struct rdtgroup *pr, *cr;
+
+	if (!r->mon_enabled)
+		return;
+
+	list_for_each_entry(pr, &rdt_all_groups, rdtgroup_list) {
+		parent_kn = pr->mon_data_kn;
+		mkdir_mondata_subdir(parent_kn, domid, r, pr);
+
+		list_for_each_entry(cr, &pr->crdtgrp_list, crdtgrp_list) {
+			parent_kn = cr->mon_data_kn;
+			mkdir_mondata_subdir(parent_kn, domid, r, cr);
+		}
+	}
+}
+
 static int mkdir_mondata_subdir_alldom(struct kernfs_node *parent_kn,
 				       struct rdt_resource *r,
 				       struct rdtgroup *pr)
-- 
1.9.1