[Xen-devel] [PATCH v6 01/14] x86: add socket_to_cpumask

[Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>]

Maintain socket_to_cpumask which contains all the HT and core siblings
in the same socket.

Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/smpboot.c    | 15 +++++++++++++++
 xen/include/asm-x86/smp.h |  8 ++++++++
 2 files changed, 23 insertions(+)

diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 116c8f8..d236f18 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -59,6 +59,9 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_mask);
 cpumask_t cpu_online_map __read_mostly;
 EXPORT_SYMBOL(cpu_online_map);
 
+unsigned int nr_sockets __read_mostly;
+cpumask_t *socket_to_cpumask __read_mostly;
+
 struct cpuinfo_x86 cpu_data[NR_CPUS];
 
 u32 x86_cpu_to_apicid[NR_CPUS] __read_mostly =
@@ -301,6 +304,8 @@ static void set_cpu_sibling_map(int cpu)
             }
         }
     }
+
+    cpumask_set_cpu(cpu, &socket_to_cpumask[cpu_to_socket(cpu)]);
 }
 
 void start_secondary(void *unused)
@@ -717,6 +722,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 
     stack_base[0] = stack_start;
 
+    nr_sockets = DIV_ROUND_UP(nr_cpu_ids, boot_cpu_data.x86_max_cores *
+                                          boot_cpu_data.x86_num_siblings);
+    ASSERT(nr_sockets > 0);
+
+    socket_to_cpumask = xzalloc_array(cpumask_t, nr_sockets);
+    if ( !socket_to_cpumask )
+        panic("No memory for socket CPU siblings map");
+
     if ( !zalloc_cpumask_var(&per_cpu(cpu_sibling_mask, 0)) ||
          !zalloc_cpumask_var(&per_cpu(cpu_core_mask, 0)) )
         panic("No memory for boot CPU sibling/core maps");
@@ -782,6 +795,8 @@ remove_siblinginfo(int cpu)
     int sibling;
     struct cpuinfo_x86 *c = cpu_data;
 
+    cpumask_clear_cpu(cpu, &socket_to_cpumask[cpu_to_socket(cpu)]);
+
     for_each_cpu ( sibling, per_cpu(cpu_core_mask, cpu) )
     {
         cpumask_clear_cpu(cpu, per_cpu(cpu_core_mask, sibling));
diff --git a/xen/include/asm-x86/smp.h b/xen/include/asm-x86/smp.h
index 67518cf..3ffddde 100644
--- a/xen/include/asm-x86/smp.h
+++ b/xen/include/asm-x86/smp.h
@@ -58,6 +58,14 @@ int hard_smp_processor_id(void);
 
 void __stop_this_cpu(void);
 
+/*
+ * This value is considered to not change from the initial startup.
+ * Otherwise all the relevant places need to be retrofitted.
+ */
+extern unsigned int nr_sockets;
+
+/* Representing HT and core siblings in each socket */
+extern cpumask_t *socket_to_cpumask;
 #endif /* !__ASSEMBLY__ */
 
 #endif
-- 
1.9.1


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