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From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
	daniel@iogearbox.net
Cc: magnus.karlsson@intel.com, bjorn.topel@intel.com,
	Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Subject: [PATCH bpf-next 2/2] xsk: implement map_gen_lookup() callback for XSKMAP
Date: Thu, 24 Oct 2019 09:19:31 +0200	[thread overview]
Message-ID: <20191024071931.3628-3-maciej.fijalkowski@intel.com> (raw)
In-Reply-To: <20191024071931.3628-1-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 86e3027d4605..0103405f639a 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -165,6 +165,22 @@ 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)
 {
@@ -305,6 +321,7 @@ 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


      parent reply	other threads:[~2019-10-24 14:25 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24  7:19 [PATCH bpf-next 0/2] xsk: XSKMAP lookup improvements Maciej Fijalkowski
2019-10-24  7:19 ` [PATCH bpf-next 1/2] xsk: store struct xdp_sock as a flexible array member of the XSKMAP Maciej Fijalkowski
2019-10-24 20:12   ` Jakub Kicinski
2019-10-24  7:19 ` Maciej Fijalkowski [this message]

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