On Tue, Aug 31, 2021 at 3:51 PM Joanne Koong <joannekoong@xxxxxx> wrote:
>
> This patch adds the libbpf infrastructure that will allow the user to
> specify the number of hash functions to use for the bloom filter map.
>
> Signed-off-by: Joanne Koong <joannekoong@xxxxxx>
> ---
> tools/lib/bpf/bpf.c | 2 ++
> tools/lib/bpf/bpf.h | 1 +
> tools/lib/bpf/libbpf.c | 32 +++++++++++++++++++++++++++++++-
> tools/lib/bpf/libbpf.h | 3 +++
> tools/lib/bpf/libbpf.map | 2 ++
> tools/lib/bpf/libbpf_internal.h | 4 +++-
> 6 files changed, 42 insertions(+), 2 deletions(-)
>
[...]
> __u32 bpf_map__key_size(const struct bpf_map *map)
> {
> return map->def.key_size;
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index f177d897c5f7..497b84772be8 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -538,6 +538,9 @@ LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
> /* get/set map if_index */
> LIBBPF_API __u32 bpf_map__ifindex(const struct bpf_map *map);
> LIBBPF_API int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
> +/* get/set nr_hashes. used for bloom filter maps */
> +LIBBPF_API __u32 bpf_map__nr_hashes(const struct bpf_map *map);
> +LIBBPF_API int bpf_map__set_nr_hashes(struct bpf_map *map, __u32 nr_hashes);
>
> typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
> LIBBPF_API int bpf_map__set_priv(struct bpf_map *map, void *priv,
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index bbc53bb25f68..372c2478274f 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -385,4 +385,6 @@ LIBBPF_0.5.0 {
> btf__load_vmlinux_btf;
> btf_dump__dump_type_data;
> libbpf_set_strict_mode;
> + bpf_map__nr_hashes;
> + bpf_map__set_nr_hashes;
I'd really like to avoid this very niche and specific set of APIs. As
I mentioned on first patch, I think nr_hash can be easily passed
through map_flags property.
> } LIBBPF_0.4.0;
> diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
> index 533b0211f40a..501ae042980d 100644
> --- a/tools/lib/bpf/libbpf_internal.h
> +++ b/tools/lib/bpf/libbpf_internal.h
> @@ -171,8 +171,9 @@ enum map_def_parts {
> MAP_DEF_NUMA_NODE = 0x080,
> MAP_DEF_PINNING = 0x100,
> MAP_DEF_INNER_MAP = 0x200,
> + MAP_DEF_NR_HASHES = 0x400,
>
> - MAP_DEF_ALL = 0x3ff, /* combination of all above */
> + MAP_DEF_ALL = 0x7ff, /* combination of all above */
> };
>
> struct btf_map_def {
> @@ -186,6 +187,7 @@ struct btf_map_def {
> __u32 map_flags;
> __u32 numa_node;
> __u32 pinning;
> + __u32 nr_hashes; /* used for bloom filter maps */
we can't extend btf_map_def, it's fixed indefinitely
> };
>
> int parse_btf_map_def(const char *map_name, struct btf *btf,
> --
> 2.30.2
>
