hello Jiri and Yotam,
On Thu, 2017-09-28 at 19:34 +0200, Jiri Pirko wrote:
> From: Yotam Gigi <yot...@mellanox.com>
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 19e64bf..ada8214 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -772,6 +772,7 @@ struct sk_buff {
> __u8 remcsum_offload:1;
> #ifdef CONFIG_NET_SWITCHDEV
> __u8 offload_fwd_mark:1;
> + __u8 offload_mr_fwd_mark:1;
I had a look at the pahole output:
$ make allyesconfig
$ make net/core/skbuff.o
$ pahole net/core/skbuff.o | grep -C7 tc_from_ingress
__u8 ipvs_property:1; /* 147: 7 1 */
__u8 inner_protocol_type:1; /* 147: 6 1 */
__u8 remcsum_offload:1; /* 147: 5 1 */
__u8 offload_fwd_mark:1; /* 147: 4 1 */
__u8 tc_skip_classify:1; /* 147: 3 1 */
__u8 tc_at_ingress:1; /* 147: 2 1 */
__u8 tc_redirected:1; /* 147: 1 1 */
__u8 tc_from_ingress:1; /* 147: 0 1 */
__u16 tc_index; /* 148 2 */
/* XXX 2 bytes hole, try to pack */
union {
__wsum csum; /* 4 */
struct {
apparently there are no more spare bits to use at that offset: therefore,
adding 'offload_mr_fwd_mark' before 'tc_skip_classify' will make
'tc_from_ingress' slip at offset 148, and tc_index at offset 150.
I think you can use that 2-bytes hole below tc_index, and also move the
offload_fwd_mark bit there, as we use both when CONFIG_NET_SWITCHDEV is
enabled. This way we will also gain one spare bit, without changing the
struct size or worsening the cacheline alignments.
what do you think?
regards,
--
davide
