From 8f8449384ec364ba2a654f11f94e754e4ff719e0 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 11 Nov 2016 10:55:10 -0800 Subject: [PATCH] bpf: Add BPF_MAP_TYPE_LRU_PERCPU_HASH Provide a LRU version of the existing BPF_MAP_TYPE_PERCPU_HASH Signed-off-by: Martin KaFai Lau Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 3 +- kernel/bpf/hashtab.c | 129 +++++++++++++++++++++++++++++++++++++-- kernel/bpf/syscall.c | 8 ++- 3 files changed, 131 insertions(+), 9 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ed8c6799fb14..7d9b2832c280 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -86,6 +86,7 @@ enum bpf_map_type { BPF_MAP_TYPE_STACK_TRACE, BPF_MAP_TYPE_CGROUP_ARRAY, BPF_MAP_TYPE_LRU_HASH, + BPF_MAP_TYPE_LRU_PERCPU_HASH, }; enum bpf_prog_type { @@ -108,7 +109,7 @@ enum bpf_prog_type { #define BPF_F_NO_PREALLOC (1U << 0) /* Instead of having one common LRU list in the - * BPF_MAP_TYPE_LRU_HASH map, use a percpu LRU list + * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list * which can scale and perform better. * Note, the LRU nodes (including free nodes) cannot be moved * across different LRU lists. diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 4a9e71a7c41f..34debc1a9641 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -62,7 +62,14 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node); static bool htab_is_lru(const struct bpf_htab *htab) { - return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH; + return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH || + htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH; +} + +static bool htab_is_percpu(const struct bpf_htab *htab) +{ + return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH || + htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH; } static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size, @@ -85,7 +92,7 @@ static void htab_free_elems(struct bpf_htab *htab) { int i; - if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH) + if (!htab_is_percpu(htab)) goto free_elems; for (i = 0; i < htab->map.max_entries; i++) { @@ -122,7 +129,7 @@ static int prealloc_init(struct bpf_htab *htab) if (!htab->elems) return -ENOMEM; - if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH) + if (!htab_is_percpu(htab)) goto skip_percpu_elems; for (i = 0; i < htab->map.max_entries; i++) { @@ -195,8 +202,10 @@ static int alloc_extra_elems(struct bpf_htab *htab) /* Called from syscall */ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) { - bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_HASH; - bool lru = attr->map_type == BPF_MAP_TYPE_LRU_HASH; + bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); /* percpu_lru means each cpu has its own LRU list. * it is different from BPF_MAP_TYPE_PERCPU_HASH where * the map's value itself is percpu. percpu_lru has @@ -823,12 +832,84 @@ err: return ret; } +static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 map_flags, + bool onallcpus) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + struct htab_elem *l_new = NULL, *l_old; + struct hlist_head *head; + unsigned long flags; + struct bucket *b; + u32 key_size, hash; + int ret; + + if (unlikely(map_flags > BPF_EXIST)) + /* unknown flags */ + return -EINVAL; + + WARN_ON_ONCE(!rcu_read_lock_held()); + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size); + + b = __select_bucket(htab, hash); + head = &b->head; + + /* For LRU, we need to alloc before taking bucket's + * spinlock because LRU's elem alloc may need + * to remove older elem from htab and this removal + * operation will need a bucket lock. + */ + if (map_flags != BPF_EXIST) { + l_new = prealloc_lru_pop(htab, key, hash); + if (!l_new) + return -ENOMEM; + } + + /* bpf_map_update_elem() can be called in_irq() */ + raw_spin_lock_irqsave(&b->lock, flags); + + l_old = lookup_elem_raw(head, hash, key, key_size); + + ret = check_flags(htab, l_old, map_flags); + if (ret) + goto err; + + if (l_old) { + bpf_lru_node_set_ref(&l_old->lru_node); + + /* per-cpu hash map can update value in-place */ + pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size), + value, onallcpus); + } else { + pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size), + value, onallcpus); + hlist_add_head_rcu(&l_new->hash_node, head); + l_new = NULL; + } + ret = 0; +err: + raw_spin_unlock_irqrestore(&b->lock, flags); + if (l_new) + bpf_lru_push_free(&htab->lru, &l_new->lru_node); + return ret; +} + static int htab_percpu_map_update_elem(struct bpf_map *map, void *key, void *value, u64 map_flags) { return __htab_percpu_map_update_elem(map, key, value, map_flags, false); } +static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 map_flags) +{ + return __htab_lru_percpu_map_update_elem(map, key, value, map_flags, + false); +} + /* Called from syscall or from eBPF program */ static int htab_map_delete_elem(struct bpf_map *map, void *key) { @@ -976,8 +1057,21 @@ static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key) return NULL; } +static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key) +{ + struct htab_elem *l = __htab_map_lookup_elem(map, key); + + if (l) { + bpf_lru_node_set_ref(&l->lru_node); + return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size)); + } + + return NULL; +} + int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value) { + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); struct htab_elem *l; void __percpu *pptr; int ret = -ENOENT; @@ -993,6 +1087,8 @@ int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value) l = __htab_map_lookup_elem(map, key); if (!l) goto out; + if (htab_is_lru(htab)) + bpf_lru_node_set_ref(&l->lru_node); pptr = htab_elem_get_ptr(l, map->key_size); for_each_possible_cpu(cpu) { bpf_long_memcpy(value + off, @@ -1008,10 +1104,16 @@ out: int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, u64 map_flags) { + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); int ret; rcu_read_lock(); - ret = __htab_percpu_map_update_elem(map, key, value, map_flags, true); + if (htab_is_lru(htab)) + ret = __htab_lru_percpu_map_update_elem(map, key, value, + map_flags, true); + else + ret = __htab_percpu_map_update_elem(map, key, value, map_flags, + true); rcu_read_unlock(); return ret; @@ -1031,11 +1133,26 @@ static struct bpf_map_type_list htab_percpu_type __read_mostly = { .type = BPF_MAP_TYPE_PERCPU_HASH, }; +static const struct bpf_map_ops htab_lru_percpu_ops = { + .map_alloc = htab_map_alloc, + .map_free = htab_map_free, + .map_get_next_key = htab_map_get_next_key, + .map_lookup_elem = htab_lru_percpu_map_lookup_elem, + .map_update_elem = htab_lru_percpu_map_update_elem, + .map_delete_elem = htab_lru_map_delete_elem, +}; + +static struct bpf_map_type_list htab_lru_percpu_type __read_mostly = { + .ops = &htab_lru_percpu_ops, + .type = BPF_MAP_TYPE_LRU_PERCPU_HASH, +}; + static int __init register_htab_map(void) { bpf_register_map_type(&htab_type); bpf_register_map_type(&htab_percpu_type); bpf_register_map_type(&htab_lru_type); + bpf_register_map_type(&htab_lru_percpu_type); return 0; } late_initcall(register_htab_map); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 233e3ac836a6..ce1b7de7d72c 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -292,6 +292,7 @@ static int map_lookup_elem(union bpf_attr *attr) goto free_key; if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) value_size = round_up(map->value_size, 8) * num_possible_cpus(); else @@ -302,7 +303,8 @@ static int map_lookup_elem(union bpf_attr *attr) if (!value) goto free_key; - if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { + if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { err = bpf_percpu_hash_copy(map, key, value); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_copy(map, key, value); @@ -366,6 +368,7 @@ static int map_update_elem(union bpf_attr *attr) goto free_key; if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) value_size = round_up(map->value_size, 8) * num_possible_cpus(); else @@ -385,7 +388,8 @@ static int map_update_elem(union bpf_attr *attr) */ preempt_disable(); __this_cpu_inc(bpf_prog_active); - if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { + if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { err = bpf_percpu_hash_update(map, key, value, attr->flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_update(map, key, value, attr->flags); -- 2.20.1