Subject: [PATCH bpf-next v9 23/34] bpf: eliminate rlimit-based memory accounting for hashtab maps

From: Roman Gushchin <[email-masked]>
Date: Tue, 1 Dec 2020 13:58:49 -0800

Do not use rlimit-based memory accounting for hashtab maps.
It has been replaced with the memcg-based memory accounting.

Signed-off-by: Roman Gushchin <[email-masked]>
Acked-by: Song Liu <[email-masked]>
---
 kernel/bpf/hashtab.c | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index bf70fb3ed9c1..fe7a0733a63a 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -443,7 +443,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 	bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
 	struct bpf_htab *htab;
 	int err, i;
-	u64 cost;
 
 	htab = kzalloc(sizeof(*htab), GFP_USER | __GFP_ACCOUNT);
 	if (!htab)
@@ -481,26 +480,12 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 	    htab->n_buckets > U32_MAX / sizeof(struct bucket))
 		goto free_htab;
 
-	cost = (u64) htab->n_buckets * sizeof(struct bucket) +
-	       (u64) htab->elem_size * htab->map.max_entries;
-
-	if (percpu)
-		cost += (u64) round_up(htab->map.value_size, 8) *
-			num_possible_cpus() * htab->map.max_entries;
-	else
-	       cost += (u64) htab->elem_size * num_possible_cpus();
-
-	/* if map size is larger than memlock limit, reject it */
-	err = bpf_map_charge_init(&htab->map.memory, cost);
-	if (err)
-		goto free_htab;
-
 	err = -ENOMEM;
 	htab->buckets = bpf_map_area_alloc(htab->n_buckets *
 					   sizeof(struct bucket),
 					   htab->map.numa_node);
 	if (!htab->buckets)
-		goto free_charge;
+		goto free_htab;
 
 	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
 		htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
@@ -541,8 +526,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
 		free_percpu(htab->map_locked[i]);
 	bpf_map_area_free(htab->buckets);
-free_charge:
-	bpf_map_charge_finish(&htab->map.memory);
 free_htab:
 	lockdep_unregister_key(&htab->lockdep_key);
 	kfree(htab);
-- 
2.26.2