x86/intel_rdt/cqm: Add CPU hotplug support

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@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-26-git-send-email-vikas.shivappa@linux.intel.com

3 files changed, 90 insertions, 7 deletions

diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 050ea15259ea..f12bb91b8c66 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -479,6 +479,13 @@ 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);
 }
 
 static void domain_remove_cpu(int cpu, struct rdt_resource *r)
@@ -494,6 +501,12 @@ 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);
                 kfree(d->rmid_busy_llc);
                 list_del(&d->list);
@@ -501,13 +514,14 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
         }
 }
 
-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(rdt_cpu_default.closid, 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)
@@ -515,29 +529,42 @@ 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;
 }
 
+static void clear_childcpus(struct rdtgroup *r, unsigned int cpu)
+{
+        struct rdtgroup *cr;
+
+        list_for_each_entry(cr, &r->mon.crdtgrp_list, mon.crdtgrp_list) {
+                if (cpumask_test_and_clear_cpu(cpu, &cr->cpu_mask)) {
+                        break;
+                }
+        }
+}
+
 static int intel_rdt_offline_cpu(unsigned int cpu)
 {
         struct rdtgroup *rdtgrp;
         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))
+                if (cpumask_test_and_clear_cpu(cpu, &rdtgrp->cpu_mask)) {
+                        clear_childcpus(rdtgrp, 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 7fcaa5f82bd0..2660d15d1712 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -301,6 +301,11 @@ 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++)                                                             \
@@ -360,5 +365,9 @@ void free_rmid(u32 rmid);
 int 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,
+                                    struct rdt_domain *d);
 
 #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 0a7be9b7a201..ea37b972df4f 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1323,6 +1323,27 @@ 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 *prgrp, *crgrp;
+        char name[32];
+
+        if (!r->mon_enabled)
+                return;
+
+        list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
+                sprintf(name, "mon_%s_%02d", r->name, dom_id);
+                kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
+
+                list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
+                        kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
+        }
+}
+
 static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
                                 struct rdt_domain *d,
                                 struct rdt_resource *r, struct rdtgroup *prgrp)
@@ -1369,6 +1390,32 @@ out_destroy:
         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,
+                                    struct rdt_domain *d)
+{
+        struct kernfs_node *parent_kn;
+        struct rdtgroup *prgrp, *crgrp;
+        struct list_head *head;
+
+        if (!r->mon_enabled)
+                return;
+
+        list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
+                parent_kn = prgrp->mon.mon_data_kn;
+                mkdir_mondata_subdir(parent_kn, d, r, prgrp);
+
+                head = &prgrp->mon.crdtgrp_list;
+                list_for_each_entry(crgrp, head, mon.crdtgrp_list) {
+                        parent_kn = crgrp->mon.mon_data_kn;
+                        mkdir_mondata_subdir(parent_kn, d, r, crgrp);
+                }
+        }
+}
+
 static int mkdir_mondata_subdir_alldom(struct kernfs_node *parent_kn,
                                        struct rdt_resource *r,
                                        struct rdtgroup *prgrp)