Re: [PATCH bpf-next v2 13/35] bpf: eliminate rlimit-based memory accounting for arraymap maps

[Song Liu]

On Mon, Jul 27, 2020 at 12:26 PM Roman Gushchin <guro@xxxxxx> wrote:
>
> Do not use rlimit-based memory accounting for arraymap 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/arraymap.c | 24 ++++--------------------
>  1 file changed, 4 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
> index 9597fecff8da..41581c38b31d 100644
> --- a/kernel/bpf/arraymap.c
> +++ b/kernel/bpf/arraymap.c
> @@ -75,11 +75,10 @@ int array_map_alloc_check(union bpf_attr *attr)
>  static struct bpf_map *array_map_alloc(union bpf_attr *attr)
>  {
>         bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
> -       int ret, numa_node = bpf_map_attr_numa_node(attr);
> +       int numa_node = bpf_map_attr_numa_node(attr);
>         u32 elem_size, index_mask, max_entries;
>         bool bypass_spec_v1 = bpf_bypass_spec_v1();
> -       u64 cost, array_size, mask64;
> -       struct bpf_map_memory mem;
> +       u64 array_size, mask64;
>         struct bpf_array *array;
>
>         elem_size = round_up(attr->value_size, 8);
> @@ -120,44 +119,29 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
>                 }
>         }
>
> -       /* make sure there is no u32 overflow later in round_up() */
> -       cost = array_size;
> -       if (percpu)
> -               cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
> -
> -       ret = bpf_map_charge_init(&mem, cost);
> -       if (ret < 0)
> -               return ERR_PTR(ret);
> -
>         /* allocate all map elements and zero-initialize them */
>         if (attr->map_flags & BPF_F_MMAPABLE) {
>                 void *data;
>
>                 /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
>                 data = bpf_map_area_mmapable_alloc(array_size, numa_node);
> -               if (!data) {
> -                       bpf_map_charge_finish(&mem);
> +               if (!data)
>                         return ERR_PTR(-ENOMEM);
> -               }
>                 array = data + PAGE_ALIGN(sizeof(struct bpf_array))
>                         - offsetof(struct bpf_array, value);
>         } else {
>                 array = bpf_map_area_alloc(array_size, numa_node);
>         }
> -       if (!array) {
> -               bpf_map_charge_finish(&mem);
> +       if (!array)
>                 return ERR_PTR(-ENOMEM);
> -       }
>         array->index_mask = index_mask;
>         array->map.bypass_spec_v1 = bypass_spec_v1;
>
>         /* copy mandatory map attributes */
>         bpf_map_init_from_attr(&array->map, attr);
> -       bpf_map_charge_move(&array->map.memory, &mem);
>         array->elem_size = elem_size;
>
>         if (percpu && bpf_array_alloc_percpu(array)) {
> -               bpf_map_charge_finish(&array->map.memory);
>                 bpf_map_area_free(array);
>                 return ERR_PTR(-ENOMEM);
>         }
> --
> 2.26.2
>