From: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> Date: Tue, 15 Oct 2024 08:36:24 +0200 > On Mon, 2024-10-14 at 13:55 -0700, Kuniyuki Iwashima wrote: > > CONFIG_WEXT_CORE cannot be built as a module > > Isn't that precisely an argument for _not_ using net->gen[] with all the > additional dynamic allocations that implies? Exactly... Recently I was thinking most of the structs in struct net (except for first-class citizens like ipv4/ipv6) should use net->gen[] given the distro kernel enables most configs. But yes, WEXT is always built-in. > I'm not really against > doing this, but it does make the third patch more complex, requiring the > new wext_net->net pointer, Right, FWIW, before posting this patch, I checked 5 structs have a similar pointer. rdma_dev_net : possible_net_t net pktgen_net : struct net netns_ipvs : struct net bond_net : struct net afs_net : struct net > and given allocations (rounded up) will take > more space - for something always present - than just going with the > existing scheme? > > What's the reason to use net->gen[]? Probably because wext_nlevents was just before a cacheline on my setup ? $ pahole -EC net vmlinux | grep net_generic -C 30 ... } wext_nlevents; /* 2536 24 */ /* --- cacheline 40 boundary (2560 bytes) --- */ struct net_generic * gen; /* 2560 8 */
