[PATCH bpf-next v3 2/2] bpf: implement map_gen_lookup() callback for XSKMAP
From: Björn Töpel <hidden>
Date: 2019-10-25 09:32:54
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Inline the xsk_map_lookup_elem() via implementing the map_gen_lookup() callback. This results in emitting the bpf instructions in place of bpf_map_lookup_elem() helper call and better performance of bpf programs. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> --- kernel/bpf/xskmap.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index a83e92fe2971..62ce88e57d98 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c@@ -163,6 +163,22 @@ struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map, u32 key) return xs; } +static u32 xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) +{ + const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2; + struct bpf_insn *insn = insn_buf; + + *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0); + *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5); + *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *))); + *insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map)); + *insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp); + *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0); + *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *insn++ = BPF_MOV64_IMM(ret, 0); + return insn - insn_buf; +} + int __xsk_map_redirect(struct bpf_map *map, struct xdp_buff *xdp, struct xdp_sock *xs) {
@@ -303,6 +319,7 @@ const struct bpf_map_ops xsk_map_ops = { .map_free = xsk_map_free, .map_get_next_key = xsk_map_get_next_key, .map_lookup_elem = xsk_map_lookup_elem, + .map_gen_lookup = xsk_map_gen_lookup, .map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only, .map_update_elem = xsk_map_update_elem, .map_delete_elem = xsk_map_delete_elem,
--
2.20.1