From: Shaohua Li <shaohua.li@intel.com>

We should flush cache at CPU hotplug.  An error has been observed data is
corrupted after CPU hotplug in CPUs with bigger cache.

Signed-off-by: Shaohua.li<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 arch/x86_64/kernel/process.c |    1 +
 1 files changed, 1 insertion(+)

diff -puN arch/x86_64/kernel/process.c~x86_64-cpu-hotplug-support-fix arch/x86_64/kernel/process.c
--- 25/arch/x86_64/kernel/process.c~x86_64-cpu-hotplug-support-fix	2005-06-09 23:53:09.000000000 -0700
+++ 25-akpm/arch/x86_64/kernel/process.c	2005-06-09 23:53:09.000000000 -0700
@@ -163,6 +163,7 @@ DECLARE_PER_CPU(int, cpu_state);
 static inline void play_dead(void)
 {
 	idle_task_exit();
+	wbinvd();
 	mb();
 	/* Ack it */
 	__get_cpu_var(cpu_state) = CPU_DEAD;
_