Re: [PATCH bpf-next v2 24/35] bpf: eliminate rlimit-based memory accounting for stackmap maps

[Song Liu]

On Mon, Jul 27, 2020 at 12:22 PM Roman Gushchin <guro@xxxxxx> wrote:
>
> Do not use rlimit-based memory accounting for stackmap maps.
> It has been replaced with the memcg-based memory accounting.
>
> Signed-off-by: Roman Gushchin <guro@xxxxxx>

Acked-by: Song Liu <songliubraving@xxxxxx>

> ---
>  kernel/bpf/stackmap.c | 16 +++-------------
>  1 file changed, 3 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
> index 5beb2f8c23da..9ac0f405beef 100644
> --- a/kernel/bpf/stackmap.c
> +++ b/kernel/bpf/stackmap.c
> @@ -90,7 +90,6 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
>  {
>         u32 value_size = attr->value_size;
>         struct bpf_stack_map *smap;
> -       struct bpf_map_memory mem;
>         u64 cost, n_buckets;
>         int err;
>
> @@ -119,15 +118,9 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
>
>         cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
>         cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
> -       err = bpf_map_charge_init(&mem, cost);
> -       if (err)
> -               return ERR_PTR(err);
> -
>         smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
> -       if (!smap) {
> -               bpf_map_charge_finish(&mem);
> +       if (!smap)
>                 return ERR_PTR(-ENOMEM);
> -       }
>
>         bpf_map_init_from_attr(&smap->map, attr);
>         smap->map.value_size = value_size;
> @@ -135,20 +128,17 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
>
>         err = get_callchain_buffers(sysctl_perf_event_max_stack);
>         if (err)
> -               goto free_charge;
> +               goto free_smap;
>
>         err = prealloc_elems_and_freelist(smap);
>         if (err)
>                 goto put_buffers;
>
> -       bpf_map_charge_move(&smap->map.memory, &mem);
> -
>         return &smap->map;
>
>  put_buffers:
>         put_callchain_buffers();
> -free_charge:
> -       bpf_map_charge_finish(&mem);
> +free_smap:
>         bpf_map_area_free(smap);
>         return ERR_PTR(err);
>  }
> --
> 2.26.2
>