[PATCH bpf-next 4/5] libbpf: Set read_format PERF_FORMAT_LOST on kprobe perf fds
From: Daniel Xu <hidden>
Date: 2019-09-17 13:31:51
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
There is no way to get the nmissed count from kprobes that are created using the perf API. The previous commits added read_format support for this count. Enable it in this commit. Signed-off-by: Daniel Xu <redacted> --- tools/lib/bpf/libbpf.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1ca0acd1d823..43f45f6d914d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c@@ -5031,7 +5031,7 @@ static int determine_uprobe_retprobe_bit(void) } static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, - uint64_t offset, int pid) + uint64_t offset, int pid, uint64_t read_format) { struct perf_event_attr attr = {}; char errmsg[STRERR_BUFSIZE];
@@ -5060,6 +5060,7 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, } attr.size = sizeof(attr); attr.type = type; + attr.read_format = read_format; attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */ attr.config2 = offset; /* kprobe_addr or probe_offset */
@@ -5087,7 +5088,8 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog, int pfd, err; pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name, - 0 /* offset */, -1 /* pid */); + 0 /* offset */, -1 /* pid */, + PERF_FORMAT_LOST /* read_format */); if (pfd < 0) { pr_warning("program '%s': failed to create %s '%s' perf event: %s\n", bpf_program__title(prog, false),
@@ -5118,7 +5120,8 @@ struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog, int pfd, err; pfd = perf_event_open_probe(true /* uprobe */, retprobe, - binary_path, func_offset, pid); + binary_path, func_offset, pid, + 0 /* read_format */); if (pfd < 0) { pr_warning("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n", bpf_program__title(prog, false),
--
2.21.0