Linux Virtualization - Apr 2007 - [PATCH 3/3] Gdt hotplug

As suggested by Andi Kleen, don't allocate a GDT page if there is already
one
present.  Needed for CPU hotplug.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Index: linux-2.6.14-rc1/arch/i386/kernel/smpboot.c
==================================================================---
linux-2.6.14-rc1.orig/arch/i386/kernel/smpboot.c	2005-09-20 20:38:22.000000000
-0700
+++ linux-2.6.14-rc1/arch/i386/kernel/smpboot.c	2005-09-28 12:54:08.000000000
-0700
@@ -898,7 +898,8 @@ static int __devinit do_boot_cpu(int api
 	 * This grunge runs the startup process for
 	 * the targeted processor.
 	 */
-	cpu_gdt_descr[cpu].address = __get_free_page(GFP_KERNEL|__GFP_ZERO);
+	if (!cpu_gdt_descr[cpu].address)
+		cpu_gdt_descr[cpu].address = __get_free_page(GFP_KERNEL|__GFP_ZERO);
 
 	atomic_set(&init_deasserted, 0);

On Wednesday 28 September 2005 23:44, Zachary Amsden
wrote:
> As suggested by Andi Kleen, don't allocate a GDT page if there is
already
> one present.  Needed for CPU hotplug.
Did I really suggest that? I think I suggested checking the return
value of gfp. Also get_zeroed_page() is slightly cleaner than GFP_ZERO.

-Andi
>
> Signed-off-by: Zachary Amsden <zach@vmware.com>
> Index: linux-2.6.14-rc1/arch/i386/kernel/smpboot.c
> ==================================================================> ---
linux-2.6.14-rc1.orig/arch/i386/kernel/smpboot.c	2005-09-20
> 20:38:22.000000000 -0700 +++
> linux-2.6.14-rc1/arch/i386/kernel/smpboot.c	2005-09-28 12:54:08.000000000
> -0700 @@ -898,7 +898,8 @@ static int __devinit do_boot_cpu(int api
>  	 * This grunge runs the startup process for
>  	 * the targeted processor.
>  	 */
> -	cpu_gdt_descr[cpu].address = __get_free_page(GFP_KERNEL|__GFP_ZERO);
> +	if (!cpu_gdt_descr[cpu].address)
> +		cpu_gdt_descr[cpu].address = __get_free_page(GFP_KERNEL|__GFP_ZERO);
>
>  	atomic_set(&init_deasserted, 0);