Re: [PATCH] Fix cpu offline bug

[Keir Fraser <keir.xen@gmail.com>]

Good fix of a nasty bug! I think I will refactor this a bit and do it
slightly differently, but the (simple) principle will of course be the same.

 Thanks,
 Keir

On 04/03/2011 10:22, "Liu, Jinsong" <jinsong.liu@intel.com> wrote:

> Fix cpu offline bug
> 
> At current xen, when cpu offline, cpu0 will wait the 1st cpu offline;
> However, if offline 2nd, 3rd, ... cpu, cpu0 will not wait it.
> This patch is used to fix the bug.
> 
> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
> 
> diff -r d1631540bcc4 xen/arch/x86/smpboot.c
> --- a/xen/arch/x86/smpboot.c Tue Jan 18 17:23:24 2011 +0000
> +++ b/xen/arch/x86/smpboot.c Sat Feb 12 03:48:09 2011 +0800
> @@ -78,7 +78,8 @@ static enum cpu_state {
>      CPU_STATE_INIT,     /* master -> slave: Early bringup phase 1 */
>      CPU_STATE_CALLOUT,  /* master -> slave: Early bringup phase 2 */
>      CPU_STATE_CALLIN,   /* slave -> master: Completed phase 2 */
> -    CPU_STATE_ONLINE    /* master -> slave: Go fully online now. */
> +    CPU_STATE_ONLINE,   /* master -> slave: Go fully online now. */
> +    CPU_STATE_STAY      /* after slave dead, global cpu_state stay here */
>  } cpu_state;
>  #define set_cpu_state(state) do { mb(); cpu_state = (state); } while (0)
>  
> @@ -867,6 +868,8 @@ void __cpu_die(unsigned int cpu)
>          if ( (++i % 10) == 0 )
>              printk(KERN_ERR "CPU %u still not dead...\n", cpu);
>      }
> +
> +    set_cpu_state(CPU_STATE_STAY);
>  }
>  
>  int cpu_add(uint32_t apic_id, uint32_t acpi_id, uint32_t pxm)