Re: [RFC 11/13] genapic: reduce stack pressuge in io_apic.c step 3 target_cpus

From: Bert Wesarg
Date: Sun Sep 07 2008 - 03:55:37 EST


On Sun, Sep 7, 2008 at 01:50, Mike Travis <travis@xxxxxxx> wrote:
> * Step 3 "target_cpus" of cleaning up io_apic.c modifies the TARGET_CPUS
> interface to pass a pointer to the returned mask for arch X86_64,
> removing yet another "cpumask_t variable on the stack".
>
> target_cpus = TARGET_CPUS;
>
> becomes:
>
> TARGET_CPUS(target_cpus);
>
> For x86_32 this is expanded to:
>
> target_cpus = (genapic->target_cpus());
>
> For x86_64 this is expanded to:
>
> target_cpus = (genapic->target_cpus)(&(target_cpus));
But its expended to:
(genapic->target_cpus)(&(target_cpus));

> -#define TARGET_CPUS (genapic->target_cpus())
> +#define TARGET_CPUS(retval) (genapic->target_cpus)(&(retval))


> +#ifdef CONFIG_X86_64
> +#define TARGET_CPUS(retval) (genapic->target_cpus)(&(retval))
> +#else
> +#define TARGET_CPUS(retval) retval = (genapic->target_cpus())
> +#endif

Bert
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