Commit 835f1fca authored Mar 05, 2023 by Yafang Shao Committed by Alexei Starovoitov Mar 07, 2023

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>

parent 71a49abe

kernel/bpf/cpumap.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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,
		};