On Wed, 12 Feb 2025 16:55:52 +0100 Alexander Lobakin wrote:
> > You mean to cache napi_id in gro_node?
> >
> > Then we get +8 bytes to sizeof(napi_struct) for little reason...
Right but I think the expectation would be that we don't ever touch
that on the fast path, right? The "real" napi_id would basically
go down below:
/* control-path-only fields follow */
8B of cold data doesn't matter at all. But I haven't checked if
we need the napi->napi_id access anywhere hot, do we?
> > Dunno, if you really prefer, I can do it that way.
>
> Alternative to avoid +8 bytes:
>
> struct napi_struct {
> ...
>
> union {
> struct gro_node gro;
> struct {
> u8 pad[offsetof(struct gro_node, napi_id)];
> u32 napi_id;
> };
> };
>
> This is effectively the same what struct_group() does, just more ugly.
> But allows to declare gro_node separately.
