hi,
this patchset adds new link type BPF_TRACE_KPROBE_MULTI that attaches
kprobe program through fprobe API [1] instroduced by Masami.
The fprobe API allows to attach probe on multiple functions at once very
fast, because it works on top of ftrace. On the other hand this limits
the probe point to the function entry or return.
With bpftrace support I see following attach speed:
# perf stat --null -r 5 ./src/bpftrace -e 'kprobe:x* { } i:ms:1 { exit(); } '
Attaching 2 probes...
Attaching 3342 functions
...
1.4960 +- 0.0285 seconds time elapsed ( +- 1.91% )
v2 changes:
- based on latest fprobe changes [1]
- renaming the uapi interface to kprobe multi
- adding support for sort_r to pass user pointer for swap functions
and using that in cookie support to keep just single functions array
- moving new link to kernel/trace/bpf_trace.c file
- using single fprobe callback function for entry and exit
- using kvzalloc, libbpf_ensure_mem functions
- adding new k[ret]probe.multi sections instead of using current kprobe
- used glob_match from test_progs.c, added '?' matching
- move bpf_get_func_ip verifier inline change to seprate change
- couple of other minor fixes
Also available at:
https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
bpf/kprobe_multi
thanks,
jirka
[1] https://lore.kernel.org/bpf/164458044634.586276.3261555265565111183.stgit@devnote2/
---
Jiri Olsa (10):
lib/sort: Add priv pointer to swap function
bpf: Add multi kprobe link
bpf: Add bpf_get_func_ip kprobe helper for multi kprobe link
bpf: Add support to inline bpf_get_func_ip helper on x86
bpf: Add cookie support to programs attached with kprobe multi link
libbpf: Add libbpf_kallsyms_parse function
libbpf: Add bpf_link_create support for multi kprobes
libbpf: Add bpf_program__attach_kprobe_opts support for multi kprobes
selftest/bpf: Add kprobe_multi attach test
selftest/bpf: Add kprobe_multi test for bpf_cookie values
include/linux/bpf_types.h | 1 +
include/linux/sort.h | 4 +-
include/linux/trace_events.h | 6 ++
include/linux/types.h | 1 +
include/uapi/linux/bpf.h | 14 ++++
kernel/bpf/syscall.c | 26 ++++++--
kernel/bpf/verifier.c | 21 +++++-
kernel/trace/bpf_trace.c | 331 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
lib/sort.c | 42 +++++++++---
tools/include/uapi/linux/bpf.h | 14 ++++
tools/lib/bpf/bpf.c | 7 ++
tools/lib/bpf/bpf.h | 9 ++-
tools/lib/bpf/libbpf.c | 192 +++++++++++++++++++++++++++++++++++++++++++++--------
tools/lib/bpf/libbpf_internal.h | 5 ++
tools/testing/selftests/bpf/prog_tests/bpf_cookie.c | 72 ++++++++++++++++++++
tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c | 115 ++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/kprobe_multi.c | 58 ++++++++++++++++
tools/testing/selftests/bpf/progs/kprobe_multi_bpf_cookie.c | 62 +++++++++++++++++
18 files changed, 930 insertions(+), 50 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi.c
create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi_bpf_cookie.c
