On Mon, Apr 25, 2022 at 11:42 AM Takshak Chahande <ctakshak@xxxxxx> wrote:
>
> This patch extends batch operations support for map-in-map map-types:
> BPF_MAP_TYPE_HASH_OF_MAPS and BPF_MAP_TYPE_ARRAY_OF_MAPS
>
> A usecase where outer HASH map holds hundred of VIP entries and its
> associated reuse-ports per VIP stored in REUSEPORT_SOCKARRAY type
> inner map, needs to do batch operation for performance gain.
>
> This patch leverages the exiting generic functions for most of the batch
> operations. As map-in-map's value contains the actual reference of the inner map,
> for BPF_MAP_TYPE_HASH_OF_MAPS type, it needed an extra step to fetch the
> map_id from the reference value.
>
> selftests are added in next patch that has v1->v3 changes
>
> Signed-off-by: Takshak Chahande <ctakshak@xxxxxx>
> ---
cc'ing Yonghong who was involved in designing and implementing these
batch APIs. PTAL when you get a chance, thanks!
> kernel/bpf/arraymap.c | 2 ++
> kernel/bpf/hashtab.c | 12 ++++++++++--
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
> index 7f145aefbff8..f0852b6617cc 100644
> --- a/kernel/bpf/arraymap.c
> +++ b/kernel/bpf/arraymap.c
> @@ -1344,6 +1344,8 @@ const struct bpf_map_ops array_of_maps_map_ops = {
> .map_fd_put_ptr = bpf_map_fd_put_ptr,
> .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
> .map_gen_lookup = array_of_map_gen_lookup,
> + .map_lookup_batch = generic_map_lookup_batch,
> + .map_update_batch = generic_map_update_batch,
> .map_check_btf = map_check_no_btf,
> .map_btf_name = "bpf_array",
> .map_btf_id = &array_of_maps_map_btf_id,
> diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
> index c68fbebc8c00..fd537bfba84c 100644
> --- a/kernel/bpf/hashtab.c
> +++ b/kernel/bpf/hashtab.c
> @@ -139,7 +139,7 @@ static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
>
> static void htab_init_buckets(struct bpf_htab *htab)
> {
> - unsigned i;
> + unsigned int i;
>
> for (i = 0; i < htab->n_buckets; i++) {
> INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
> @@ -1594,7 +1594,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
> void __user *uvalues = u64_to_user_ptr(attr->batch.values);
> void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
> void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
> - u32 batch, max_count, size, bucket_size;
> + u32 batch, max_count, size, bucket_size, map_id;
> struct htab_elem *node_to_free = NULL;
> u64 elem_map_flags, map_flags;
> struct hlist_nulls_head *head;
> @@ -1719,6 +1719,13 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map,
> }
> } else {
> value = l->key + roundup_key_size;
> + if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
> + struct bpf_map **inner_map = value;
> + /* Actual value is the id of the inner map */
> + map_id = map->ops->map_fd_sys_lookup_elem(*inner_map);
> + value = &map_id;
> + }
> +
> if (elem_map_flags & BPF_F_LOCK)
> copy_map_value_locked(map, dst_val, value,
> true);
> @@ -2425,6 +2432,7 @@ const struct bpf_map_ops htab_of_maps_map_ops = {
> .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
> .map_gen_lookup = htab_of_map_gen_lookup,
> .map_check_btf = map_check_no_btf,
> + BATCH_OPS(htab),
> .map_btf_name = "bpf_htab",
> .map_btf_id = &htab_of_maps_map_btf_id,
> };
> --
> 2.30.2
>
