Re: [PATCH bpf-next v2 17/35] bpf: eliminate rlimit-based memory accounting for devmap maps

[Song Liu]

On Mon, Jul 27, 2020 at 12:20 PM Roman Gushchin <guro@xxxxxx> wrote:
>
> Do not use rlimit-based memory accounting for devmap 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/devmap.c | 18 ++----------------
>  1 file changed, 2 insertions(+), 16 deletions(-)
>
> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> index 05bf93088063..8148c7260a54 100644
> --- a/kernel/bpf/devmap.c
> +++ b/kernel/bpf/devmap.c
> @@ -109,8 +109,6 @@ static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
>  static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
>  {
>         u32 valsize = attr->value_size;
> -       u64 cost = 0;
> -       int err;
>
>         /* check sanity of attributes. 2 value sizes supported:
>          * 4 bytes: ifindex
> @@ -135,21 +133,13 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
>
>                 if (!dtab->n_buckets) /* Overflow check */
>                         return -EINVAL;
> -               cost += (u64) sizeof(struct hlist_head) * dtab->n_buckets;
> -       } else {
> -               cost += (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
>         }
>
> -       /* if map size is larger than memlock limit, reject it */
> -       err = bpf_map_charge_init(&dtab->map.memory, cost);
> -       if (err)
> -               return -EINVAL;
> -
>         if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
>                 dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
>                                                            dtab->map.numa_node);
>                 if (!dtab->dev_index_head)
> -                       goto free_charge;
> +                       return -ENOMEM;
>
>                 spin_lock_init(&dtab->index_lock);
>         } else {
> @@ -157,14 +147,10 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
>                                                       sizeof(struct bpf_dtab_netdev *),
>                                                       dtab->map.numa_node);
>                 if (!dtab->netdev_map)
> -                       goto free_charge;
> +                       return -ENOMEM;
>         }
>
>         return 0;
> -
> -free_charge:
> -       bpf_map_charge_finish(&dtab->map.memory);
> -       return -ENOMEM;
>  }
>
>  static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
> --
> 2.26.2
>