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| author | Yonghong Song <yhs@fb.com> | 2017-10-24 08:53:08 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-25 03:47:47 +0200 |
| commit | e87c6bc3852b981e71c757be20771546ce9f76f3 (patch) | |
| tree | bad3be630137d8e873f4ad5a1ea77b4aa1853184 /include/trace/perf.h | |
| parent | bpf: use the same condition in perf event set/free bpf handler (diff) | |
| download | linux-e87c6bc3852b981e71c757be20771546ce9f76f3.tar.xz linux-e87c6bc3852b981e71c757be20771546ce9f76f3.zip | |
bpf: permit multiple bpf attachments for a single perf event
This patch enables multiple bpf attachments for a
kprobe/uprobe/tracepoint single trace event.
Each trace_event keeps a list of attached perf events.
When an event happens, all attached bpf programs will
be executed based on the order of attachment.
A global bpf_event_mutex lock is introduced to protect
prog_array attaching and detaching. An alternative will
be introduce a mutex lock in every trace_event_call
structure, but it takes a lot of extra memory.
So a global bpf_event_mutex lock is a good compromise.
The bpf prog detachment involves allocation of memory.
If the allocation fails, a dummy do-nothing program
will replace to-be-detached program in-place.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/trace/perf.h')
| -rw-r--r-- | include/trace/perf.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/trace/perf.h b/include/trace/perf.h index 04fe68bbe767..14f127b6acf5 100644 --- a/include/trace/perf.h +++ b/include/trace/perf.h @@ -34,7 +34,6 @@ perf_trace_##call(void *__data, proto) \ struct trace_event_call *event_call = __data; \ struct trace_event_data_offsets_##call __maybe_unused __data_offsets;\ struct trace_event_raw_##call *entry; \ - struct bpf_prog *prog = event_call->prog; \ struct pt_regs *__regs; \ u64 __count = 1; \ struct task_struct *__task = NULL; \ @@ -46,8 +45,9 @@ perf_trace_##call(void *__data, proto) \ __data_size = trace_event_get_offsets_##call(&__data_offsets, args); \ \ head = this_cpu_ptr(event_call->perf_events); \ - if (!prog && __builtin_constant_p(!__task) && !__task && \ - hlist_empty(head)) \ + if (!bpf_prog_array_valid(event_call) && \ + __builtin_constant_p(!__task) && !__task && \ + hlist_empty(head)) \ return; \ \ __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\ |