Re: [PATCH net-next] core: simplify the getting percpu of flow_cache

[Eric Dumazet <eric.dumazet@gmail.com>]

On Thu, 2013-03-28 at 20:24 +0800, roy.qing.li@gmail.com wrote:
> From: Li RongQing <roy.qing.li@gmail.com>
> 
> replace per_cpu with per_cpu_ptr to save conversion between address and pointer
> 
> Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
> ---
>  net/core/flow.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/flow.c b/net/core/flow.c
> index 7fae135..707fb7b 100644
> --- a/net/core/flow.c
> +++ b/net/core/flow.c
> @@ -334,7 +334,7 @@ static int flow_cache_percpu_empty(struct flow_cache *fc, int cpu)
>  	struct flow_cache_percpu *fcp;
>  	int i;
>  
> -	fcp = &per_cpu(*fc->percpu, cpu);
> +	fcp = per_cpu_ptr(fc->percpu, cpu);
>  	for (i = 0; i < flow_cache_hash_size(fc); i++)
>  		if (!hlist_empty(&fcp->hash_table[i]))
>  			return 0;


This makes no difference at all, at least on x86

Care to elaborate ?