diff options
| author |   Ilya Leoshkevich <iii@linux.ibm.com> | 2025-08-06 18:22:41 +0200 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2025-08-07 09:01:41 -0700 |
| commit | 9474e27a24a41e55d0ac2b77d8171fddec7dbb87 (patch) | |
| tree | ebc01697c97408eaf8e24073cb5c1d913af08fe3 | |
| parent | bpf: Fix memory leak of bpf_scc_info objects (diff) | |
| download | wireguard-linux-9474e27a24a41e55d0ac2b77d8171fddec7dbb87.tar.xz wireguard-linux-9474e27a24a41e55d0ac2b77d8171fddec7dbb87.zip | |
libbpf: Add the ability to suppress perf event enablement
Automatically enabling a perf event after attaching a BPF prog to it is
not always desirable.
Add a new "dont_enable" field to struct bpf_perf_event_opts. While
introducing "enable" instead would be nicer in that it would avoid
a double negation in the implementation, it would make
DECLARE_LIBBPF_OPTS() less efficient.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Suggested-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Co-developed-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20250806162417.19666-2-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 13 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.h | 4 |
2 files changed, 11 insertions, 6 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index fb4d92c5c339..8f5a81b672e1 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10965,11 +10965,14 @@ struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *p } link->link.fd = pfd; } - if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { - err = -errno; - pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", - prog->name, pfd, errstr(err)); - goto err_out; + + if (!OPTS_GET(opts, dont_enable, false)) { + if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { + err = -errno; + pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", + prog->name, pfd, errstr(err)); + goto err_out; + } } return &link->link; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d1cf813a057b..455a957cb702 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -499,9 +499,11 @@ struct bpf_perf_event_opts { __u64 bpf_cookie; /* don't use BPF link when attach BPF program */ bool force_ioctl_attach; + /* don't automatically enable the event */ + bool dont_enable; size_t :0; }; -#define bpf_perf_event_opts__last_field force_ioctl_attach +#define bpf_perf_event_opts__last_field dont_enable LIBBPF_API struct bpf_link * bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd); |