From: Hou Tao <houtao1@xxxxxxxxxx>
Hi,
> trie_mem_usage() is introduced to calculate the lpm_trie memory usage.
> Some small memory allocations are ignored. The inner node is also
> ignored.
>
> The result as follows,
>
> - before
> 10: lpm_trie flags 0x1
> key 8B value 8B max_entries 65536 memlock 1048576B
>
> - after
> 10: lpm_trie flags 0x1
> key 8B value 8B max_entries 65536 memlock 2291536B
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> kernel/bpf/lpm_trie.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
> index d833496..e0ca08e 100644
> --- a/kernel/bpf/lpm_trie.c
> +++ b/kernel/bpf/lpm_trie.c
> @@ -720,6 +720,16 @@ static int trie_check_btf(const struct bpf_map *map,
> -EINVAL : 0;
> }
>
> +static u64 trie_mem_usage(const struct bpf_map *map)
> +{
> + struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
> + u64 elem_size;
> +
> + elem_size = sizeof(struct lpm_trie_node) + trie->data_size +
> + trie->map.value_size;
> + return elem_size * trie->n_entries;
Need to use READ_ONCE(trie->n_entries) because all updates of n_entries are protected by trie->lock and here it is a lockless read.
> +}
> +
> BTF_ID_LIST_SINGLE(trie_map_btf_ids, struct, lpm_trie)
> const struct bpf_map_ops trie_map_ops = {
> .map_meta_equal = bpf_map_meta_equal,
> @@ -733,5 +743,6 @@ static int trie_check_btf(const struct bpf_map *map,
> .map_update_batch = generic_map_update_batch,
> .map_delete_batch = generic_map_delete_batch,
> .map_check_btf = trie_check_btf,
> + .map_mem_usage = trie_mem_usage,
> .map_btf_id = &trie_map_btf_ids[0],
> };
> --
> 1.8.3.1
>
