Commit 434bcbc8 authored by Donglin Peng's avatar Donglin Peng Committed by Andrii Nakryiko
Browse files

bpf: Optimize the performance of find_bpffs_btf_enums 



Currently, vmlinux BTF is unconditionally sorted during
the build phase. The function btf_find_by_name_kind
executes the binary search branch, so find_bpffs_btf_enums
can be optimized by using btf_find_by_name_kind.

Signed-off-by: default avatarDonglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-10-dolinux.peng@gmail.com
parent dc893cfa

kernel/bpf/inode.c

+17 −25
Original line number Diff line number Diff line
@@ -600,10 +600,17 @@ struct bpffs_btf_enums { 


static int find_bpffs_btf_enums(struct bpffs_btf_enums *info)

{

	const struct btf *btf;

	const struct btf_type *t;

	struct {

		const struct btf_type **type;

		const char *name;

	int i, n;

	} btf_enums[] = {

		{&info->cmd_t,		"bpf_cmd"},

		{&info->map_t,		"bpf_map_type"},

		{&info->prog_t,		"bpf_prog_type"},

		{&info->attach_t,	"bpf_attach_type"},

	};

	const struct btf *btf;

	int i, id;



	memset(info, 0, sizeof(*info));
@@ -615,31 +622,16 @@ static int find_bpffs_btf_enums(struct bpffs_btf_enums *info) 


	info->btf = btf;



	for (i = 1, n = btf_nr_types(btf); i < n; i++) {

		t = btf_type_by_id(btf, i);

		if (!btf_type_is_enum(t))

			continue;



		name = btf_name_by_offset(btf, t->name_off);

		if (!name)

			continue;



		if (strcmp(name, "bpf_cmd") == 0)

			info->cmd_t = t;

		else if (strcmp(name, "bpf_map_type") == 0)

			info->map_t = t;

		else if (strcmp(name, "bpf_prog_type") == 0)

			info->prog_t = t;

		else if (strcmp(name, "bpf_attach_type") == 0)

			info->attach_t = t;

		else

			continue;

	for (i = 0; i < ARRAY_SIZE(btf_enums); i++) {

		id = btf_find_by_name_kind(btf, btf_enums[i].name,

					   BTF_KIND_ENUM);

		if (id < 0)

			return -ESRCH;



		if (info->cmd_t && info->map_t && info->prog_t && info->attach_t)

			return 0;

		*btf_enums[i].type = btf_type_by_id(btf, id);

	}



	return -ESRCH;

	return 0;

}



static bool find_btf_enum_const(const struct btf *btf, const struct btf_type *enum_t,