From: Jakub Kicinski <jakub.kicin...@netronome.com>
Date: Tue, 27 Oct 2015 11:16:03 +0000
> On Mon, 26 Oct 2015 18:23:07 -0700 (PDT), David Miller wrote:
>> From: Jakub Kicinski <jakub.kicin...@netronome.com>
>> Date: Fri, 23 Oct 2015 19:58:11 +0100
>>
>> > +struct nfp_net_tx_buf {
>> > + struct sk_buff *skb;
>> > + dma_addr_t dma_addr;
>> > + short int fidx;
>> > + u16 pkt_cnt;
>> > + u32 real_len;
>> > +};
>>
>> This packs very poorly, and has a lot of padding holes. Better ordering
>> would be:
>>
>> struct nfp_net_tx_buf {
>> struct sk_buff *skb;
>> dma_addr_t dma_addr;
>> u32 real_len;
>> short int fidx;
>> u16 pkt_cnt;
>> };
>
> Seems to pack fine on x86:
>
> struct nfp_net_tx_buf {
> struct sk_buff * skb; /* 0 8 */
> dma_addr_t dma_addr; /* 8 8 */
> short int fidx; /* 16 2 */
> u16 pkt_cnt; /* 18 2 */
> u32 real_len; /* 20 4 */
>
> /* size: 24, cachelines: 1, members: 5 */
> /* last cacheline: 24 bytes */
> };
>
> Are my packing skills deceiving me? Maybe I'll try to build the driver
> for more esoteric architectures.
My bad, I misread the types.
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