netdev - Re: [net-next PATCH] net: reduce cycles spend on ICMP replies that gets rate limited

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Date:   Fri, 06 Jan 2017 11:40:21 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Jesper Dangaard Brouer <brouer@...hat.com>
Cc:     netdev@...r.kernel.org
Subject: Re: [net-next PATCH] net: reduce cycles spend on ICMP replies that
 gets rate limited

On Fri, 2017-01-06 at 18:39 +0100, Jesper Dangaard Brouer wrote:


> @@ -648,13 +668,17 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
>  		}
>  	}
>  
> -	icmp_param = kmalloc(sizeof(*icmp_param), GFP_ATOMIC);
> -	if (!icmp_param)
> -		return;
> -
>  	sk = icmp_xmit_lock(net);
>  	if (!sk)
> -		goto out_free;
> +		goto out;
> +
> +	/* Check global sysctl_icmp_msgs_per_sec ratelimit */
> +	if (!icmpv4_global_allow(net, type, code))
> +		goto out_unlock;
> +
> +	icmp_param = kmalloc(sizeof(*icmp_param), GFP_ATOMIC);
> +	if (!icmp_param)
> +		goto out_unlock;


Truth be told, I have no idea why we allocate dynamic memory for "struct
icmp_bxm " : It is 112 bytes.