Commit 9263dddc authored by Takshak Chahande's avatar Takshak Chahande Committed by Alexei Starovoitov
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bpf: Extend batch operations for map-in-map bpf-maps 



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 2/2.

Signed-off-by: default avatarTakshak Chahande <ctakshak@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220510082221.2390540-1-ctakshak@fb.com
parent 174efa78

kernel/bpf/arraymap.c

+2 −0
Original line number Diff line number Diff line
@@ -1345,6 +1345,8 @@ 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_id = &array_map_btf_ids[0],

};

kernel/bpf/hashtab.c

+11 −2
Original line number Diff line number Diff line
@@ -140,7 +140,7 @@ 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);
@@ -1627,7 +1627,7 @@ __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;
@@ -1752,6 +1752,14 @@ __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);
@@ -2450,5 +2458,6 @@ 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_id = &htab_map_btf_ids[0],

};