bpf: Eliminate rlimit-based memory accounting infra for bpf maps
Remove rlimit-based accounting infrastructure code, which is not used
anymore.
To provide a backward compatibility, use an approximation of the
bpf map memory footprint as a "memlock" value, available to a user
via map info. The approximation is based on the maximal number of
elements and key and value sizes.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-33-guro@fb.com
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index dff3a5f..29096d9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -128,7 +128,7 @@ static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
return map;
}
-static u32 bpf_map_value_size(struct bpf_map *map)
+static u32 bpf_map_value_size(const struct bpf_map *map)
{
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
@@ -346,77 +346,6 @@ void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
map->numa_node = bpf_map_attr_numa_node(attr);
}
-static int bpf_charge_memlock(struct user_struct *user, u32 pages)
-{
- unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-
- if (atomic_long_add_return(pages, &user->locked_vm) > memlock_limit) {
- atomic_long_sub(pages, &user->locked_vm);
- return -EPERM;
- }
- return 0;
-}
-
-static void bpf_uncharge_memlock(struct user_struct *user, u32 pages)
-{
- if (user)
- atomic_long_sub(pages, &user->locked_vm);
-}
-
-int bpf_map_charge_init(struct bpf_map_memory *mem, u64 size)
-{
- u32 pages = round_up(size, PAGE_SIZE) >> PAGE_SHIFT;
- struct user_struct *user;
- int ret;
-
- if (size >= U32_MAX - PAGE_SIZE)
- return -E2BIG;
-
- user = get_current_user();
- ret = bpf_charge_memlock(user, pages);
- if (ret) {
- free_uid(user);
- return ret;
- }
-
- mem->pages = pages;
- mem->user = user;
-
- return 0;
-}
-
-void bpf_map_charge_finish(struct bpf_map_memory *mem)
-{
- bpf_uncharge_memlock(mem->user, mem->pages);
- free_uid(mem->user);
-}
-
-void bpf_map_charge_move(struct bpf_map_memory *dst,
- struct bpf_map_memory *src)
-{
- *dst = *src;
-
- /* Make sure src will not be used for the redundant uncharging. */
- memset(src, 0, sizeof(struct bpf_map_memory));
-}
-
-int bpf_map_charge_memlock(struct bpf_map *map, u32 pages)
-{
- int ret;
-
- ret = bpf_charge_memlock(map->memory.user, pages);
- if (ret)
- return ret;
- map->memory.pages += pages;
- return ret;
-}
-
-void bpf_map_uncharge_memlock(struct bpf_map *map, u32 pages)
-{
- bpf_uncharge_memlock(map->memory.user, pages);
- map->memory.pages -= pages;
-}
-
static int bpf_map_alloc_id(struct bpf_map *map)
{
int id;
@@ -524,14 +453,11 @@ static void bpf_map_release_memcg(struct bpf_map *map)
static void bpf_map_free_deferred(struct work_struct *work)
{
struct bpf_map *map = container_of(work, struct bpf_map, work);
- struct bpf_map_memory mem;
- bpf_map_charge_move(&mem, &map->memory);
security_bpf_map_free(map);
bpf_map_release_memcg(map);
/* implementation dependent freeing */
map->ops->map_free(map);
- bpf_map_charge_finish(&mem);
}
static void bpf_map_put_uref(struct bpf_map *map)
@@ -592,6 +518,19 @@ static fmode_t map_get_sys_perms(struct bpf_map *map, struct fd f)
}
#ifdef CONFIG_PROC_FS
+/* Provides an approximation of the map's memory footprint.
+ * Used only to provide a backward compatibility and display
+ * a reasonable "memlock" info.
+ */
+static unsigned long bpf_map_memory_footprint(const struct bpf_map *map)
+{
+ unsigned long size;
+
+ size = round_up(map->key_size + bpf_map_value_size(map), 8);
+
+ return round_up(map->max_entries * size, PAGE_SIZE);
+}
+
static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
{
const struct bpf_map *map = filp->private_data;
@@ -610,7 +549,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
"value_size:\t%u\n"
"max_entries:\t%u\n"
"map_flags:\t%#x\n"
- "memlock:\t%llu\n"
+ "memlock:\t%lu\n"
"map_id:\t%u\n"
"frozen:\t%u\n",
map->map_type,
@@ -618,7 +557,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
map->value_size,
map->max_entries,
map->map_flags,
- map->memory.pages * 1ULL << PAGE_SHIFT,
+ bpf_map_memory_footprint(map),
map->id,
READ_ONCE(map->frozen));
if (type) {
@@ -861,7 +800,6 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
static int map_create(union bpf_attr *attr)
{
int numa_node = bpf_map_attr_numa_node(attr);
- struct bpf_map_memory mem;
struct bpf_map *map;
int f_flags;
int err;
@@ -960,9 +898,7 @@ static int map_create(union bpf_attr *attr)
security_bpf_map_free(map);
free_map:
btf_put(map->btf);
- bpf_map_charge_move(&mem, &map->memory);
map->ops->map_free(map);
- bpf_map_charge_finish(&mem);
return err;
}