lkml.org 
[lkml]   [2015]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/3] perf ftrace: Use ftrace_ops::private to store event pointer
Date
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, &regs, head, NULL);
+ perf_function_event(ops->private, entry, ENTRY_SIZE, &regs, 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


\
 
 \ /
  Last update: 2015-11-26 21:01    [W:0.059 / U:0.580 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site