Add bpftool support for reporting the number of used entries of htab maps by leveraging the newly added "used_entries" field in struct bpf_map_info. It works with JSON as well.
To better understand actual used memory size of a htab map, pre-allocated maps are now marked with "*" behind the "max_entries" size.
Signed-off-by: Ho-Ren (Jack) Chuang horenchuang@bytedance.com --- tools/bpf/bpftool/map.c | 9 +++++++-- tools/include/uapi/linux/bpf.h | 1 + 2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 9a6ca9f31133..0b07abae7309 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -475,6 +475,8 @@ static int show_map_close_json(int fd, struct bpf_map_info *info) jsonw_uint_field(json_wtr, "bytes_key", info->key_size); jsonw_uint_field(json_wtr, "bytes_value", info->value_size); jsonw_uint_field(json_wtr, "max_entries", info->max_entries); + if (info->type == BPF_MAP_TYPE_HASH) + jsonw_uint_field(json_wtr, "used_entries", info->used_entries);
if (memlock) jsonw_int_field(json_wtr, "bytes_memlock", atoll(memlock)); @@ -561,8 +563,11 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info) frozen_str = get_fdinfo(fd, "frozen");
show_map_header_plain(info); - printf("\tkey %uB value %uB max_entries %u", - info->key_size, info->value_size, info->max_entries); + printf("\tkey %uB value %uB max_entries %u%1s", + info->key_size, info->value_size, info->max_entries, + !(info->map_flags & BPF_F_NO_PREALLOC) ? "*" : ""); + if (info->type == BPF_MAP_TYPE_HASH) + printf(" used_entries %u", info->used_entries);
if (memlock) printf(" memlock %sB", memlock); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 17f61338f8f8..63659368cf0e 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -6215,6 +6215,7 @@ struct bpf_map_info { __u32 id; __u32 key_size; __u32 value_size; + __u32 used_entries; __u32 max_entries; __u32 map_flags; char name[BPF_OBJ_NAME_LEN];