[PATCH] x86_64: CPU hotplug support

  Experimental CPU hotplug patch for x86_64
  -----------------------------------------
This supports logical CPU online and offline.
- Test with maxcpus=1, and then kick other cpu's off to test if init code
  is all cleaned up. CONFIG_SCHED_SMT works as well.
- idle threads are forked on demand from keventd threads for clean startup

TBD:
1. Not tested on a real NUMA machine (tested with numa=fake=2)
2. Handle ACPI pieces for physical hotplug support.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Acked-by: Andi Kleen <ak@muc.de>
Acked-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Shaohua.li<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/arch/i386/mach-default/topology.c b/arch/i386/mach-default/topology.c
index 5b3e881..23395ff 100644
--- a/arch/i386/mach-default/topology.c
+++ b/arch/i386/mach-default/topology.c
@@ -73,12 +73,11 @@ static int __init topology_init(void)
 {
 	int i;
 
-	for (i = 0; i < MAX_NUMNODES; i++) {
-		if (node_online(i))
-			arch_register_node(i);
-	}
-	for (i = 0; i < NR_CPUS; i++)
-		if (cpu_possible(i)) arch_register_cpu(i);
+	for_each_online_node(i)
+		arch_register_node(i);
+
+	for_each_cpu(i)
+		arch_register_cpu(i);
 	return 0;
 }
 
@@ -88,8 +87,8 @@ static int __init topology_init(void)
 {
 	int i;
 
-	for (i = 0; i < NR_CPUS; i++)
-		if (cpu_possible(i)) arch_register_cpu(i);
+	for_each_cpu(i)
+		arch_register_cpu(i);
 	return 0;
 }