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authorJesper Dangaard Brouer <brouer@redhat.com>2017-11-01 12:44:45 +0100
committerDavid S. Miller <davem@davemloft.net>2017-11-02 16:13:14 +0900
commit03c4cc385faaa46e5877f499c6b997fef792f8d3 (patch)
tree0e384397a2bb6b6a0483b151622edbf7aaa8b99a /kernel/bpf/cpumap.c
parent14e83bf82961aeebef41976139c61ab82c84a238 (diff)
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>
Diffstat (limited to 'kernel/bpf/cpumap.c')
-rw-r--r--kernel/bpf/cpumap.c4
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 */