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authorYonghong Song <yhs@fb.com>2017-10-23 23:53:08 -0700
committerDavid S. Miller <davem@davemloft.net>2017-10-25 10:47:47 +0900
commite87c6bc3852b981e71c757be20771546ce9f76f3 (patch)
treebad3be630137d8e873f4ad5a1ea77b4aa1853184 /include/trace/perf.h
parent0b4c6841fee03e096b735074a0c4aab3a8e92986 (diff)
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.h6
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),\