[PATCH 08/21] xen/sched: Link CPU topology to scheduler and display via xl info

[Hirokazu Takahashi <taka@xxxxxxxxxxxxx>]

Make CPU topology information available to the Xen scheduler.
Additionally, ensure that this topology information is displayed
when executing the 'xl info -n' command.
---
 xen/arch/arm/include/asm/processor.h  |  6 ++-
 xen/arch/arm/smpboot.c                | 10 +++--
 xen/common/device-tree/cpu_topology.c | 54 +++++++++++++++++++++++++++
 xen/common/sched/credit2.c            |  3 ++
 xen/common/sysctl.c                   |  1 +
 xen/include/xen/cpu_topology.h        |  3 ++
 6 files changed, 73 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/include/asm/processor.h 
b/xen/arch/arm/include/asm/processor.h
index 895d7cd502..066966b375 100644
--- a/xen/arch/arm/include/asm/processor.h
+++ b/xen/arch/arm/include/asm/processor.h
@@ -591,9 +591,13 @@ void show_stack(const struct cpu_user_regs *regs);
 
 #define cpu_relax() barrier() /* Could yield? */
 
-/* All a bit UP for the moment */
+#ifdef CONFIG_DT_CPU_TOPOLOGY
+#define cpu_to_core(_cpu)   (cpu_topology[_cpu].to_core)
+#define cpu_to_socket(_cpu)   (cpu_topology[_cpu].to_socket)
+#else /* CONFIG_DT_CPU_TOPOLOGY */
 #define cpu_to_core(_cpu)   (0)
 #define cpu_to_socket(_cpu) (0)
+#endif /* CONFIG_DT_CPU_TOPOLOGY */
 
 struct vcpu;
 void vcpu_regs_hyp_to_user(const struct vcpu *vcpu,
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index ff8b0d07e9..726f3720ce 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -93,13 +93,17 @@ static int setup_cpu_sibling_map(int cpu)
          !zalloc_cpumask_var(&per_cpu(cpu_core_mask, cpu)) )
         return -ENOMEM;
 
+#ifdef CONFIG_DT_CPU_TOPOLOGY
+    cpumask_copy(per_cpu(cpu_sibling_mask, cpu), 
&cpu_topology[cpu].thread_sibling);
+    cpumask_copy(per_cpu(cpu_core_mask, cpu), &cpu_topology[cpu].core_sibling);
+#else /* CONFIG_DT_CPU_TOPOLOGY */
     /*
-     * Currently we assume there is no multithread and NUMA, so
-     * a CPU is a sibling with itself, and the all possible CPUs
-     * are supposed to belong to the same socket (NUMA node).
+     * If CONFIG_DT_CPU_TOPOLOGY is disabled, it is assumed that
+     * all CPUs reside in the same socket and that SMT is not used.
      */
     cpumask_set_cpu(cpu, per_cpu(cpu_sibling_mask, cpu));
     cpumask_copy(per_cpu(cpu_core_mask, cpu), &cpu_possible_map);
+#endif /* CONFIG_DT_CPU_TOPOLOGY */
 
     return 0;
 }
diff --git a/xen/common/device-tree/cpu_topology.c 
b/xen/common/device-tree/cpu_topology.c
index 6c78a74778..f5d2a59e2c 100644
--- a/xen/common/device-tree/cpu_topology.c
+++ b/xen/common/device-tree/cpu_topology.c
@@ -275,6 +275,58 @@ static void __init fixup_topology(void)
 }
 
 
+static void __init setup_topology_for_sched(void)
+{
+    int prev_socketid = 0;
+    int prev_clusterid = 0;
+    int prev_coreid = 0;
+    int prev_threadid = 0;
+    int coreid = 0;
+    int socketid = 0;
+    int clusterid = 0;
+    int threadid = 0;
+    int cpu;
+
+    for_each_possible_cpu(cpu)
+    {
+        struct cpu_topology *cpu_topo = &cpu_topology[cpu];
+
+        if (cpu_topo->package_id != prev_socketid)
+        {
+            prev_socketid = cpu_topo->package_id;
+            prev_clusterid = cpu_topo->cluster_id;
+            prev_coreid = cpu_topo->core_id;
+            socketid++;
+            clusterid++;
+            coreid++;
+            threadid++;
+        }
+        else if (cpu_topo->cluster_id != prev_clusterid)
+        {
+            prev_clusterid = cpu_topo->cluster_id;
+            prev_coreid = cpu_topo->core_id;
+            clusterid++;
+            coreid++;
+            threadid++;
+        }
+        else if (cpu_topo->core_id != prev_coreid)
+        {
+            prev_coreid = cpu_topo->core_id;
+            coreid++;
+            threadid++;
+        }
+        else if (cpu_topo->thread_id != prev_threadid)
+        {
+            threadid++;
+        }
+
+        cpu_topo->to_socket = socketid;
+        cpu_topo->to_core = coreid;
+        cpu_topo->num_siblings = cpumask_weight(&cpu_topo->thread_sibling);
+    }
+
+}
+
 int __init parse_dt_topology(void)
 {
     struct dt_device_node *cpus;
@@ -304,4 +356,6 @@ void __init dt_init_cpu_topology(void)
 
     for_each_possible_cpu(cpu)
         setup_siblings_masks(cpu);
+
+    setup_topology_for_sched();
 }
diff --git a/xen/common/sched/credit2.c b/xen/common/sched/credit2.c
index 75316d42b7..34876b99c0 100644
--- a/xen/common/sched/credit2.c
+++ b/xen/common/sched/credit2.c
@@ -20,6 +20,7 @@
 #include <xen/softirq.h>
 #include <xen/time.h>
 #include <xen/trace.h>
+#include <xen/cpu_topology.h>
 
 #include <asm/div64.h>
 
@@ -38,6 +39,8 @@ static unsigned int cpu_nr_siblings(unsigned int cpu)
 {
 #ifdef CONFIG_X86
     return cpu_data[cpu].x86_num_siblings;
+#elif CONFIG_DT_CPU_TOPOLOGY
+    return cpu_topology[cpu].num_siblings;
 #else
     return 1;
 #endif
diff --git a/xen/common/sysctl.c b/xen/common/sysctl.c
index 5207664252..806c885df1 100644
--- a/xen/common/sysctl.c
+++ b/xen/common/sysctl.c
@@ -28,6 +28,7 @@
 #include <xen/pmstat.h>
 #include <xen/livepatch.h>
 #include <xen/coverage.h>
+#include <xen/cpu_topology.h>
 
 long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
 {
diff --git a/xen/include/xen/cpu_topology.h b/xen/include/xen/cpu_topology.h
index 0cdceb9bd0..c22224b3af 100644
--- a/xen/include/xen/cpu_topology.h
+++ b/xen/include/xen/cpu_topology.h
@@ -14,6 +14,9 @@ struct cpu_topology {
     cpumask_t thread_sibling;
     cpumask_t core_sibling;
     cpumask_t cluster_sibling;
+    int to_core;
+    int to_socket;
+    int num_siblings;
 };
 
 
-- 
2.43.0