bpf: cpumap memory usage

A new helper is introduced to calculate cpumap memory usage. The size of
cpu_entries can be dynamically changed when we update or delete a cpumap
element, but this patch doesn't include the memory size of cpu_entry
yet. We can dynamically calculate the memory usage when we alloc or free
a cpu_entry, but it will take extra runtime overhead, so let just put it
aside currently. Note that the size of different cpu_entry may be
different as well.

The result as follows,
- before
48: cpumap  name count_map  flags 0x4
        key 4B  value 4B  max_entries 64  memlock 4096B

- after
48: cpumap  name count_map  flags 0x4
        key 4B  value 4B  max_entries 64  memlock 832B

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-10-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yafang Shao 2023-03-05 12:46:06 +00:00 committed by Alexei Starovoitov
parent 71a49abe73
commit 835f1fca95

View file

@ -673,6 +673,15 @@ static int cpu_map_redirect(struct bpf_map *map, u64 index, u64 flags)
__cpu_map_lookup_elem);
}
static u64 cpu_map_mem_usage(const struct bpf_map *map)
{
u64 usage = sizeof(struct bpf_cpu_map);
/* Currently the dynamically allocated elements are not counted */
usage += (u64)map->max_entries * sizeof(struct bpf_cpu_map_entry *);
return usage;
}
BTF_ID_LIST_SINGLE(cpu_map_btf_ids, struct, bpf_cpu_map)
const struct bpf_map_ops cpu_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
@ -683,6 +692,7 @@ const struct bpf_map_ops cpu_map_ops = {
.map_lookup_elem = cpu_map_lookup_elem,
.map_get_next_key = cpu_map_get_next_key,
.map_check_btf = map_check_no_btf,
.map_mem_usage = cpu_map_mem_usage,
.map_btf_id = &cpu_map_btf_ids[0],
.map_redirect = cpu_map_redirect,
};