Messages in this thread Patch in this message | | | From | Jiri Olsa <> | Subject | [PATCH 3/3] perf ftrace: Use ftrace_ops::private to store event pointer | Date | Thu, 26 Nov 2015 20:34:49 +0100 |
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Having following commands running concurently:
# perf record -e ftrace:function -a -o krava.data sleep 10 # perf record -e ftrace:function --filter 'ip == SyS_read' ls
will endup in the latter one failing on the filter rules and store all functions (in perf.data) as instructed by the first record instead of just SyS_read records.
The reason is that we don't check the ftrace_ops that triggered the event with event's ftrace_ops. Hence once running together the event from latter perf will get all the data of the event from the first one.
Fixing this by using ftrace_ops::private value to keep the perf_event pointer. This way we don't need to search for triggered event (as tracepoint handler does) and directly store sample.
Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- include/linux/perf_event.h | 3 +++ kernel/events/core.c | 25 +++++++++++++++++++++++++ kernel/trace/trace_event_perf.c | 9 ++------- 3 files changed, 30 insertions(+), 7 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index f9828a48f16a..e438f909df31 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1009,6 +1009,9 @@ extern void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, struct pt_regs *regs, struct hlist_head *head, int rctx, struct task_struct *task); +void perf_function_event(struct perf_event *event, + void *record, int entry_size, + struct pt_regs *regs, int rctx); extern void perf_bp_event(struct perf_event *event, void *data); #ifndef perf_misc_flags diff --git a/kernel/events/core.c b/kernel/events/core.c index 9fb9d5ef6825..dc98f12c55e2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7103,6 +7103,31 @@ static void perf_event_free_bpf_prog(struct perf_event *event) } } +#ifdef CONFIG_FUNCTION_TRACER +void perf_function_event(struct perf_event *event, + void *record, int entry_size, + struct pt_regs *regs, int rctx) + +{ + struct perf_sample_data data; + struct perf_raw_record raw = { + .size = entry_size, + .data = record, + }; + + if (event->hw.state & PERF_HES_STOPPED) + goto out; + + perf_sample_data_init(&data, 0, 0); + data.raw = &raw; + + perf_swevent_event(event, 1, &data, regs); + +out: + perf_swevent_put_recursion_context(rctx); +} +#endif /* CONFIG_FUNCTION_TRACER */ + #else static inline void perf_tp_register(void) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 637268855296..396a39988bde 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -318,14 +318,9 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct pt_regs *pt_regs) { struct ftrace_entry *entry; - struct hlist_head *head; struct pt_regs regs; int rctx; - head = this_cpu_ptr(event_function.perf_events); - if (hlist_empty(head)) - return; - #define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \ sizeof(u64)) - sizeof(u32)) @@ -339,8 +334,7 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, entry->ip = ip; entry->parent_ip = parent_ip; - perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0, - 1, ®s, head, NULL); + perf_function_event(ops->private, entry, ENTRY_SIZE, ®s, rctx); #undef ENTRY_SIZE } @@ -349,6 +343,7 @@ static int perf_ftrace_function_register(struct perf_event *event) { struct ftrace_ops *ops = &event->ftrace_ops; + ops->private = event; ops->flags |= FTRACE_OPS_FL_CONTROL; ops->func = perf_ftrace_function_call; return register_ftrace_function(ops); -- 2.4.3
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