From d07f0b4132a0bd1dff3a21863ad81279620693fc Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 28 Jun 2016 12:18:24 +0200 Subject: bpf, trace: fetch current cpu only once We currently have two invocations, which is unnecessary. Fetch it only once and use the smp_processor_id() variant, so we also get preemption checks along with it when DEBUG_PREEMPT is set. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/trace/bpf_trace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index de4af0208f61..c95bf2a845f6 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -296,13 +296,14 @@ __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, u64 flags, struct perf_raw_record *raw) { struct bpf_array *array = container_of(map, struct bpf_array, map); + unsigned int cpu = smp_processor_id(); u64 index = flags & BPF_F_INDEX_MASK; struct perf_sample_data sample_data; struct bpf_event_entry *ee; struct perf_event *event; if (index == BPF_F_CURRENT_CPU) - index = raw_smp_processor_id(); + index = cpu; if (unlikely(index >= array->map.max_entries)) return -E2BIG; @@ -315,7 +316,7 @@ __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map, event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) return -EINVAL; - if (unlikely(event->oncpu != smp_processor_id())) + if (unlikely(event->oncpu != cpu)) return -EOPNOTSUPP; perf_sample_data_init(&sample_data, 0, 0); -- cgit v1.2.3