Re: [6/7] Xen VMM patch set : add alloc_skb_from_cache

[James Morris]

On Fri, 19 Nov 2004, Ian Pratt wrote:

> +	/* Get the DATA. */
> +	size = SKB_DATA_ALIGN(size);
> +	data = kmem_cache_alloc(cp, gfp_mask);
> +	if (!data)
> +		goto nodata;
> +
> +	memset(skb, 0, offsetof(struct sk_buff, truesize));
> +	skb->truesize = size + sizeof(struct sk_buff);
> +	atomic_set(&skb->users, 1);
> +	skb->head = data;
> +	skb->data = data;
> +	skb->tail = data;
> +	skb->end  = data + size;
> +
> +	atomic_set(&(skb_shinfo(skb)->dataref), 1);
> +	skb_shinfo(skb)->nr_frags  = 0;
> +	skb_shinfo(skb)->tso_size = 0;
> +	skb_shinfo(skb)->tso_segs = 0;
> +	skb_shinfo(skb)->frag_list = NULL;
> +out:
> +	return skb;
> +nodata:
> +	kmem_cache_free(skbuff_head_cache, skb);
> +	skb = NULL;
> +	goto out;
> +}
> +

Most of this is duplicated code with alloc_skb(), perhaps make a function:

  __alloc_skb(size, gfp_mask, alloc_func)

Then alloc_skb() and alloc_skb_from_cache() can just be wrappers which
pass in different alloc_funcs.  I'm not sure what peformance impact this
might have though.

Thoughts?


- James
-- 
James Morris
<jmorris@xxxxxxxxxx>


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