Re: [PATCH v2] xen arm/arm64: minor improvement in smp_send_call_function_mask()

[Ian Campbell <ian.campbell@citrix.com>]

On Mon, 2014-08-25 at 15:48 +0530, Anup Patel wrote:
> Currently, smp_send_call_function_mask() function implemented
> by xen arm/arm64 will use IPI to call function on current CPU.
> 
> This means that current smp_send_call_function_mask() will do
> the following on current CPU:
> Trigger SGI for current CPU => Xen takes interrupt on current CPU
> => IPI interrupt handler will call smp_call_function_interrupt()
> 
> This patch improves the above by straight away calling
> smp_call_function_interrupt() for current CPU. This is very
> similar to smp_send_call_function_mask() implemented by Xen x86.
> 
> Changes since v1:
>  - Drop the check protecting send_SGI_mask() call

Please put this sort of thing after the --- break so it doesn't end up
in the final commit log.
> 
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> Acked-by: Julien Grall <julien.grall@linaro.org>

Acked + applied. thanks.

> ---
>  xen/arch/arm/smp.c |   13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/smp.c b/xen/arch/arm/smp.c
> index 30203b8..917d490 100644
> --- a/xen/arch/arm/smp.c
> +++ b/xen/arch/arm/smp.c
> @@ -19,7 +19,18 @@ void smp_send_event_check_mask(const cpumask_t *mask)
>  
>  void smp_send_call_function_mask(const cpumask_t *mask)
>  {
> -    send_SGI_mask(mask, GIC_SGI_CALL_FUNCTION);
> +    cpumask_t target_mask;
> +
> +    cpumask_andnot(&target_mask, mask, cpumask_of(smp_processor_id()));
> +
> +    send_SGI_mask(&target_mask, GIC_SGI_CALL_FUNCTION);
> +
> +    if ( cpumask_test_cpu(smp_processor_id(), mask) )
> +    {
> +        local_irq_disable();
> +        smp_call_function_interrupt();
> +        local_irq_enable();
> +    }
>  }
>  
>  /*