[PATCH v2 00/12] tracing: Unifying dynamic event interface

[Masami Hiramatsu <mhiramat@kernel.org>]

Hi,

This is v2 series of unifying dynamic event interface on ftrace.
Currently ftrace has 3 dynamic event interfaces, kprobes, uprobes
and synthetic. This series unifies those dynamic event interfaces
to "dynamic_events" so that we can add other dynamic events easily
on same interface, e.g. function events.
The older interfaces are left on the tracefs for backward
compatibility.

dynamic_events syntax has no difference from kprobe_events and
uprobe_events. You can use same syntax for dynamic_events interface.
For synthetic events, similar to the probe events, dynamic_events
adds "s:[GROUP/]" prefix, where the "GROUP/" must be "synthetic/".

 s:[synthetic/]<event-name> type arg [type arg]...

E.g.

 $ echo 'wakeup_latency u64 lat pid_t pid char' > synthetic_events

is same as

 $ echo 's:wakeup_latency u64 lat pid_t pid char' > dynamic_events

Or

 $ echo 's:synthetic/wakeup_latency u64 lat pid_t pid char' > dynamic_events

This series modifies synthetic event interface behavior a bit,
reorder lock dependency and related cleanups so that we can integrate
the synthetic event to dynamic_events interface. 

In this version, I changed the generic '!' erase command, which
now supports entire line style like other interfaces. So you can
delete events via dynamic_events as below

 $ cat dynamic_events | while read line; \
   do echo "!$line" >> dynamic_events; done

Also, the big change will be removing dyn_event_mutex and
synth_event_mutex because all those parts are protected by
event_mutex.

Changes from v2 are here;

New patches:
 - Reorder event_mutex and synth_event_mutex to solve
   AB-BA deadlock correctly. ([2/12])
 - Simplify creation and deletion of synthetic event. ([3/12])
 - Retern -ENOENT if there is no synthetic event when deleting ([4/12])
 - Integrate similar probe argument parsers ([5/12])
 - Use dyn_event framework for synthetic events ([9/12])
 - Remove synth_event_mutex ([10/12])
 - Remove unused APIs ([11/12])

Modified patches:
 [6/12] - [8/12]
 - Generalize delete event and export as dyn_event_release_all().
 - Add match operation for find deleting event.
 - Reorder event_mutex and dyn_event_mutex to solve lock dependency
   issue.
 - Pass const char **argv for create operation and use -ECANCELED to
   signal for trying next dyn_event_operations.
 - Remove dyn_event_mutex.

 [12/12]
 - Accept entire line, but instead of checking the given entire line
   strictly, simply checking the event and group name.

Tom, thanks for your Ack for v1 series. Since I changed many things
from v1 (not only minor change), I decided to not add your Ack for
this version. Anyway, what I've added in this version are related to
synthetic events. I need your review for those.
(especially removing synth_event_mutex)

You can try it from my git tree.

  https://github.com/mhiramat/linux/tree/unify-dynamic-events-v2

Thank you,

---

Masami Hiramatsu (12):
      tracing/uprobes: Add busy check when cleanup all uprobes
      tracing: Lock event_mutex before synth_event_mutex
      tracing: Simplify creation and deletion of synthetic event
      tracing: Integrate similar probe argument parsers
      tracing: Add unified dynamic event framework
      tracing/kprobes: Use dyn_event framework for kprobe events
      tracing/uprobes: Use dyn_event framework for uprobe events
      tracing: Use dyn_event framework for synthetic events
      tracing: Remove unneeded synth_event_mutex
      tracing: Remove orphaned trace_add/remove_event_call functions
      tracing: Add generic event-name based remove event method
      selftests/ftrace: Add testcases for dynamic event


 Documentation/trace/kprobetrace.rst                |    3 
 Documentation/trace/uprobetracer.rst               |    4 
 include/linux/trace_events.h                       |    4 
 kernel/trace/Kconfig                               |    6 
 kernel/trace/Makefile                              |    1 
 kernel/trace/trace.c                               |   12 +
 kernel/trace/trace_dynevent.c                      |  217 ++++++++++++
 kernel/trace/trace_dynevent.h                      |  119 +++++++
 kernel/trace/trace_events.c                        |   12 -
 kernel/trace/trace_events_hist.c                   |  322 ++++++++++--------
 kernel/trace/trace_kprobe.c                        |  357 ++++++++++----------
 kernel/trace/trace_probe.c                         |   74 ++++
 kernel/trace/trace_probe.h                         |    9 -
 kernel/trace/trace_uprobe.c                        |  305 ++++++++---------
 .../ftrace/test.d/dynevent/add_remove_kprobe.tc    |   30 ++
 .../ftrace/test.d/dynevent/add_remove_synth.tc     |   27 ++
 .../ftrace/test.d/dynevent/clear_select_events.tc  |   50 +++
 .../ftrace/test.d/dynevent/generic_clear_event.tc  |   49 +++
 18 files changed, 1094 insertions(+), 507 deletions(-)
 create mode 100644 kernel/trace/trace_dynevent.c
 create mode 100644 kernel/trace/trace_dynevent.h
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_kprobe.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_synth.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/clear_select_events.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/generic_clear_event.tc

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>