Commit 689eb2f1 authored by Hou Tao's avatar Hou Tao Committed by Andrii Nakryiko
Browse files

libbpf: Use page size as max_entries when probing ring buffer map 



Using page size as max_entries when probing ring buffer map, else the
probe may fail on host with 64KB page size (e.g., an ARM64 host).

After the fix, the output of "bpftool feature" on above host will be
correct.

Before :
    eBPF map_type ringbuf is NOT available
    eBPF map_type user_ringbuf is NOT available

After :
    eBPF map_type ringbuf is available
    eBPF map_type user_ringbuf is available

Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-2-houtao@huaweicloud.com
parent 47df8a2f

tools/lib/bpf/libbpf_probes.c

+1 −1
Original line number Diff line number Diff line
@@ -234,7 +234,7 @@ static int probe_map_create(enum bpf_map_type map_type) 
	case BPF_MAP_TYPE_USER_RINGBUF:

		key_size = 0;

		value_size = 0;

		max_entries = 4096;

		max_entries = sysconf(_SC_PAGE_SIZE);

		break;

	case BPF_MAP_TYPE_STRUCT_OPS:

		/* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */