Re: [PATCH 2/2] jump_label: refine placement of static_keys

From: Peter Zijlstra
Date: Wed Nov 10 2021 - 03:36:10 EST


On Tue, Nov 09, 2021 at 05:09:06PM -0800, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@xxxxxxxxxx>
>
> With CONFIG_JUMP_LABEL=y, "struct static_key" content is only
> used for the control path.
>
> Marking them __read_mostly is only needed when CONFIG_JUMP_LABEL=n.
> Otherwise we place them out of the way to increase data locality.
>
> This patch adds __static_key to centralize this new policy.
>
> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> ---
> arch/x86/kvm/lapic.c | 4 ++--
> arch/x86/kvm/x86.c | 2 +-
> include/linux/jump_label.h | 25 +++++++++++++++++--------
> kernel/events/core.c | 2 +-
> kernel/sched/fair.c | 2 +-
> net/core/dev.c | 8 ++++----
> net/netfilter/core.c | 2 +-
> net/netfilter/x_tables.c | 2 +-
> 8 files changed, 28 insertions(+), 19 deletions(-)
>

Hurmph, it's a bit cumbersome to always have to add this __static_key
attribute to every definition, and in fact you seem to have missed some.

Would something like:

typedef struct static_key __static_key static_key_t;

work? I forever seem to forget the exact things you can make a typedef
do :/