Re: [PATCH] percpu: convert SNMP mibs to new infra

From: Tejun Heo
Date: Thu Apr 02 2009 - 20:39:02 EST


Eric Dumazet wrote:
...
> #define percpu_read(var) percpu_from_op("mov", per_cpu__##var)
> #define percpu_write(var, val) percpu_to_op("mov", per_cpu__##var, val)
> #define percpu_add(var, val) percpu_to_op("add", per_cpu__##var, val)
> +#define percpu_ptr_add(var, val) percpu_to_op("add", *(var), val)
> +#define percpu_ptr_inc(var) percpu_ptr_add(var, 1)
> +#define percpu_ptr_dec(var) percpu_ptr_add(var, -1)
> #define percpu_sub(var, val) percpu_to_op("sub", per_cpu__##var, val)
> #define percpu_and(var, val) percpu_to_op("and", per_cpu__##var, val)
> #define percpu_or(var, val) percpu_to_op("or", per_cpu__##var, val)

x86 part looks fine to me.

> diff --git a/include/net/snmp.h b/include/net/snmp.h
> index 57c9362..1ba584b 100644
> --- a/include/net/snmp.h
> +++ b/include/net/snmp.h
> @@ -123,15 +123,31 @@ struct linux_xfrm_mib {
> };
>
> /*
> - * FIXME: On x86 and some other CPUs the split into user and softirq parts
> + * On x86 and some other CPUs the split into user and softirq parts
> * is not needed because addl $1,memory is atomic against interrupts (but
> - * atomic_inc would be overkill because of the lock cycles). Wants new
> - * nonlocked_atomic_inc() primitives -AK
> + * atomic_inc would be overkill because of the lock cycles).
> */
> +#ifdef CONFIG_X86
> +# define SNMP_ARRAY_SZ 1
> +#else
> +# define SNMP_ARRAY_SZ 2
> +#endif

This is quite hacky but, well, for the time being...

Thanks.

--
tejun
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