diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2017-11-01 14:44:45 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-11-02 10:13:14 +0300 |
| commit | 03c4cc385faaa46e5877f499c6b997fef792f8d3 (patch) | |
| tree | 0e384397a2bb6b6a0483b151622edbf7aaa8b99a | |
| parent | 14e83bf82961aeebef41976139c61ab82c84a238 (diff) | |
| download | linux-03c4cc385faaa46e5877f499c6b997fef792f8d3.tar.xz | |
bpf: cpumap micro-optimization in cpu_map_enqueue
Discovered that the compiler laid-out asm code in suboptimal way
when studying perf report during benchmarking of cpumap. Help
the compiler by the marking unlikely code paths.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | kernel/bpf/cpumap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 86e29cbf7827..ce5b669003b2 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -208,7 +208,7 @@ static struct xdp_pkt *convert_to_xdp_pkt(struct xdp_buff *xdp) headroom = xdp->data - xdp->data_hard_start; metasize = xdp->data - xdp->data_meta; metasize = metasize > 0 ? metasize : 0; - if ((headroom - metasize) < sizeof(*xdp_pkt)) + if (unlikely((headroom - metasize) < sizeof(*xdp_pkt))) return NULL; /* Store info in top of packet */ @@ -656,7 +656,7 @@ int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp, struct xdp_pkt *xdp_pkt; xdp_pkt = convert_to_xdp_pkt(xdp); - if (!xdp_pkt) + if (unlikely(!xdp_pkt)) return -EOVERFLOW; /* Info needed when constructing SKB on remote CPU */ |