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SubjectRe: [PACH] smp: uninline num_online_cpus() & num_possible_cpus()
On Fri, 05 Dec 2008 18:33:44 +0100
Eric Dumazet <dada1@cosmosbay.com> wrote:

> num_online_cpus() and num_possible_cpus() are not performance
> critical and are quite large.
>
> Unlining them shrinks kernel text size by 7523 bytes on x86,
> if NR_CPUS>32
>
> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
> ---
> include/linux/cpumask.h | 4 ++--
> init/main.c | 12 ++++++++++++
> 2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
> index 21e1dd4..f9b2b51 100644
> --- a/include/linux/cpumask.h
> +++ b/include/linux/cpumask.h
> @@ -507,8 +507,8 @@ extern cpumask_t cpu_present_map;
> extern cpumask_t cpu_active_map;
>
> #if NR_CPUS > 1
> -#define num_online_cpus() cpus_weight_nr(cpu_online_map)
> -#define num_possible_cpus() cpus_weight_nr(cpu_possible_map)
> +extern int num_online_cpus(void);
> +extern int num_possible_cpus(void);
> #define num_present_cpus() cpus_weight_nr(cpu_present_map)
> #define cpu_online(cpu) cpu_isset((cpu), cpu_online_map)
> #define cpu_possible(cpu) cpu_isset((cpu), cpu_possible_map)
> diff --git a/init/main.c b/init/main.c
> index 7e117a2..a1a3e55 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -376,6 +376,18 @@ EXPORT_SYMBOL(cpu_mask_all);
> int nr_cpu_ids __read_mostly = NR_CPUS;
> EXPORT_SYMBOL(nr_cpu_ids);
>
> +int num_online_cpus(void)
> +{
> + return cpus_weight_nr(cpu_online_map);
> +}
> +EXPORT_SYMBOL(num_online_cpus);
> +
> +int num_possible_cpus(void)
> +{
> + return cpus_weight_nr(cpu_possible_map);
> +}
> +EXPORT_SYMBOL(num_possible_cpus);
> +
> /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
> static void __init setup_nr_cpu_ids(void)
> {

Looks OK.

That area in init/main.c is horrid - it took quite some staring through
the ifdef tangle for me to convince myself that the code you added was
reliably SMP-only.

Perhaps sometime a lot of this cpu masky code should be moved over to
kernel/cpu.c and cleaned up.



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