[PATCH 2/3] x86: add numa_move_cpus_to_node

[Yinghai Lu <yinghai@kernel.org>]

when node only have hot add range and don't have other static range.
that node will not be onlined, and cpus on that will be linked to nearby
node with memory.
then when that host add range is added later, we need to linked those cpus
back.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 arch/x86/include/asm/numa_64.h |   10 ++++---
 arch/x86/mm/init_64.c          |    3 ++
 arch/x86/mm/numa_64.c          |   52 +++++++++++++++++++++++++++++++++++------
 3 files changed, 54 insertions(+), 11 deletions(-)

Index: linux-2.6/arch/x86/include/asm/numa_64.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/numa_64.h
+++ linux-2.6/arch/x86/include/asm/numa_64.h
@@ -25,16 +25,18 @@ extern void setup_node_bootmem(int nodei
 
 #ifdef CONFIG_NUMA
 extern void __init init_cpu_to_node(void);
-extern void __cpuinit numa_set_node(int cpu, int node);
-extern void __cpuinit numa_clear_node(int cpu);
-extern void __cpuinit numa_add_cpu(int cpu);
-extern void __cpuinit numa_remove_cpu(int cpu);
+extern void numa_set_node(int cpu, int node);
+extern void numa_clear_node(int cpu);
+extern void numa_add_cpu(int cpu);
+extern void numa_remove_cpu(int cpu);
+extern void numa_move_cpus_to_node(int nid);
 #else
 static inline void init_cpu_to_node(void)		{ }
 static inline void numa_set_node(int cpu, int node)	{ }
 static inline void numa_clear_node(int cpu)		{ }
 static inline void numa_add_cpu(int cpu, int node)	{ }
 static inline void numa_remove_cpu(int cpu)		{ }
+static inline void numa_move_cpus_to_node(int nid)	{ }
 #endif
 
 #endif /* _ASM_X86_NUMA_64_H */
Index: linux-2.6/arch/x86/mm/numa_64.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/numa_64.c
+++ linux-2.6/arch/x86/mm/numa_64.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/nodemask.h>
 #include <linux/sched.h>
+#include <linux/node.h>
 
 #include <asm/e820.h>
 #include <asm/proto.h>
@@ -660,7 +661,7 @@ void __init init_cpu_to_node(void)
 #endif
 
 
-void __cpuinit numa_set_node(int cpu, int node)
+void numa_set_node(int cpu, int node)
 {
 	int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);
 
@@ -683,19 +684,56 @@ void __cpuinit numa_set_node(int cpu, in
 		per_cpu(node_number, cpu) = node;
 }
 
-void __cpuinit numa_clear_node(int cpu)
+void numa_clear_node(int cpu)
 {
 	numa_set_node(cpu, NUMA_NO_NODE);
 }
 
+static int real_cpu_to_node(int cpu)
+{
+	int apicid, nodeid = -1;
+
+	/*
+	 * when the node doesn't have memory before, cpu_to_node(cpu) is
+	 * point to other node, but apicid_to_node still hold the real nodeid
+	 */
+	apicid = per_cpu(x86_cpu_to_apicid, cpu);
+	if (apicid == BAD_APICID)
+		return nodeid;
+
+	nodeid = apicid_to_node[apicid];
+	return nodeid;
+}
+
+void numa_move_cpus_to_node(int nid)
+{
+	int cpu;
+
+	for_each_present_cpu(cpu) {
+		int nodeid;
+
+		nodeid = real_cpu_to_node(cpu);
+		if (nodeid != nid)
+			continue;
+
+		nodeid = cpu_to_node(cpu);
+		if (nodeid != nid) {
+			unregister_cpu_under_node(cpu, nodeid);
+			numa_remove_cpu(cpu);
+			numa_set_node(cpu, nid);
+			numa_add_cpu(cpu);
+		}
+	}
+}
+
 #ifndef CONFIG_DEBUG_PER_CPU_MAPS
 
-void __cpuinit numa_add_cpu(int cpu)
+void numa_add_cpu(int cpu)
 {
 	cpumask_set_cpu(cpu, node_to_cpumask_map[early_cpu_to_node(cpu)]);
 }
 
-void __cpuinit numa_remove_cpu(int cpu)
+void numa_remove_cpu(int cpu)
 {
 	cpumask_clear_cpu(cpu, node_to_cpumask_map[early_cpu_to_node(cpu)]);
 }
@@ -705,7 +743,7 @@ void __cpuinit numa_remove_cpu(int cpu)
 /*
  * --------- debug versions of the numa functions ---------
  */
-static void __cpuinit numa_set_cpumask(int cpu, int enable)
+static void numa_set_cpumask(int cpu, int enable)
 {
 	int node = early_cpu_to_node(cpu);
 	struct cpumask *mask;
@@ -728,12 +766,12 @@ static void __cpuinit numa_set_cpumask(i
 		enable ? "numa_add_cpu" : "numa_remove_cpu", cpu, node, buf);
 }
 
-void __cpuinit numa_add_cpu(int cpu)
+void numa_add_cpu(int cpu)
 {
 	numa_set_cpumask(cpu, 1);
 }
 
-void __cpuinit numa_remove_cpu(int cpu)
+void numa_remove_cpu(int cpu)
 {
 	numa_set_cpumask(cpu, 0);
 }
Index: linux-2.6/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init_64.c
+++ linux-2.6/arch/x86/mm/init_64.c
@@ -631,6 +631,9 @@ int arch_add_memory(int nid, u64 start,
 	ret = __add_pages(nid, zone, start_pfn, nr_pages);
 	WARN_ON_ONCE(ret);
 
+	if (!ret)
+		numa_move_cpus_to_node(nid);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(arch_add_memory);