Re: [Xen-devel] [PATCH v2] complete conversion set_bit() -> __cpumask_set_cpu() by 4aaca0e9cd

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 23/02/15 13:47, Jan Beulich wrote:
> While converting to __cpumask_set_cpu() was correct, the first argument
> passed should have been corrected to be "cpu" instead of "nr" at once.
> The wrong construct results in problems on systems with relatively few
> CPUs.
>
> Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Looks better.

Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

> ---
> v2: As Andrew points out the original code was wrong too, and hence
>     the use of __cpumask_set_cpu) was correct. What was wrong was the
>     use of "nr" as the bit position.
>
> --- a/xen/common/softirq.c
> +++ b/xen/common/softirq.c
> @@ -106,7 +106,7 @@ void cpu_raise_softirq(unsigned int cpu,
>      if ( !per_cpu(batching, this_cpu) || in_irq() )
>          smp_send_event_check_cpu(cpu);
>      else
> -        __cpumask_set_cpu(nr, &per_cpu(batch_mask, this_cpu));
> +        __cpumask_set_cpu(cpu, &per_cpu(batch_mask, this_cpu));
>  }
>  
>  void cpu_raise_softirq_batch_begin(void)
>
>
>


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