On Fri, 07 Jul 2017 10:37:59 -0700
John Fastabend <[email protected]> wrote:
> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> index 36dc13de..656e334 100644
> --- a/kernel/bpf/devmap.c
> +++ b/kernel/bpf/devmap.c
[...]
>
> +void __dev_map_insert_ctx(struct bpf_map *map, u32 key)
> +{
> + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
> + unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed);
> +
> + set_bit(key, bitmap);
> +}
I don't like that this adds an atomic op (set_bit) per packet on a fast-path.
It shows up on a perf top #6 with xdp_redirect_map.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
