From: David Miller
> Sent: 09 June 2017 00:24
>
> From: Yuval Mintz <[email protected]>
> Date: Thu, 8 Jun 2017 19:13:16 +0300
>
> > @@ -67,6 +79,21 @@ struct qed_ll2_stats {
> > u64 sent_bcast_pkts;
> > };
> >
> > +struct qed_ll2_tx_pkt_info {
> > + u8 num_of_bds;
> > + u16 vlan;
> > + u8 bd_flags;
> > + u16 l4_hdr_offset_w; /* from start of packet */
> > + enum qed_ll2_tx_dest tx_dest;
> > + enum qed_ll2_roce_flavor_type qed_roce_flavor;
> > + dma_addr_t first_frag;
> > + u16 first_frag_len;
> > + bool enable_ip_cksum;
> > + bool enable_l4_cksum;
> > + bool calc_ip_len;
> > + void *cookie;
> > +};
> > +
>
> This layout is extremely inefficient, with lots of padding in between
> struct members.
>
> Group small u8 members and u16 members together so that they consume
> full 32-bit areas so you can eliminate all of the padding.
I'd also query the use of u16 sizes/lengths, any arithmetic on u16 (and u8)
variables is likely to generate extra code (on non-x86).
You are using 32 bits for the 'enum' - I bet the values fit in 8 bits,
so aren't really worried about size.
If size did matter you can easily get the above down to 32 bytes.
David
