# Re: \[PATCH v5 10/17\] net: sgi: ioc3-eth: rework skb rx handling

- From: Jakub Kicinski \<hidden\>
- Date: 2019-08-21 20:38:07 
- List: linux-input
- Page: https://ratatoskr.run/linux-input/2019/08/5694894
- Thread: https://ratatoskr.run/linux-doc/2019/08/5691925/t.md

```text
On Wed, 21 Aug 2019 16:28:47 +0200, Thomas Bogendoerfer wrote:
> > This looks like a DMA engine alignment requirement, more than an
> > optimization.  
> 
> that true, there are two constraints for the rx buffers, start must be aligned
> to 128 bytes and a buffer must not cross a 16kbyte boundary. I was already
> thinking of allocating pages and chop them up. Is there a Linux API available,
> which could help for implementing this ?
> 
> I'll probably drop this patch or only change the skb_put stuff plus RX_BUF_SIZE
> define.

Sounds a little like frag allocator (napi_alloc_frag()/
netdev_alloc_frag()), but I'm not sure you'd have sufficient control
to skip over the 16k boundary.. Perhaps others have better suggestions.
```