[PATCH v7 0/2] Tracepoint API simplification/cleanup

Mathieu Desnoyers
2014-03-21T05:19:16Z

Here is v7 of the tracepoint register/unregister API simplification,
submitted for 3.15.

Changes since v1:
- Adapt ftrace/perf callers,
- Update tracepoint.h macro,
- Build tested.

Changes since v2:
- Introduce for_each_tracepoint() iterator to allow listing the
currently loaded tracepoints, for modules using coming/going
notifiers to track tracepoints.

Changes since v3:
- Introduce module coming and going notifiers each with their own
priority to ensure that other coming notifiers are called after, and
coming notifiers are called before the tracepoint notifiers.
- Fix: move for_each_tracepoint() outside of the CONFIG_MODULE ifdef.

Changes since v4:
- Split tracepoints_mutex into two locks: tp_modlist_mutex, which
protects the tracepoint list of modules, and a tracepoint_mutex, which
protects the tracepoints per se. tracepoint_mutex nests inside
tp_modlist_mutex.
- Introduce a tracepoint module notifier, to ensure consistency between
iteration on tracepoints with for_each_tracepoint() and module coming
and going notifications. This consistency is ensured by holding
tp_modlist_mutex when calling the notifier and when iterating on the
tracepoint module list.

Changes since v5:
- Remove tracepoint_add_old_probes within "Tracepoint cleanup: remove
unused API functions" rather than in later patch.
- Remove struct tp_probes "old probes" list within "Tracepoint cleanup:
remove unused API functions", as it is not needed anymore.
- Within "Tracepoint cleanup: remove unused API functions", simply add
the new module to tail of list, since there is no need to keep it
ordered anymore.

Changes since v6:
- Remove unused struct list_head list from struct tp_probes in patch
"Tracepoint: register/unregister struct tracepoint",
- Rename for_each_tracepoint() to for_each_kernel_tracepoint(). Only
iterate on kernel tracepoints,
- Registered tracepoint module notifiers now receive struct tp_module
pointer rather than struct module pointer,
- register_tracepoint_module_notifier and
unregister_tracepoint_module_notifier now iterate on all modules and
call coming/going notifiers. This ensures notifier registration and
listing of already loaded modules are done atomically (protected by
tp_modlist_mutex).

Thanks!

Mathieu

Mathieu Desnoyers (2):
Tracepoint cleanup: remove unused API functions
Tracepoint: register/unregister struct tracepoint

include/linux/ftrace_event.h | 1 +
include/linux/tracepoint.h | 60 ++--
include/trace/ftrace.h | 2 +
kernel/trace/trace_events.c | 8 +-
kernel/tracepoint.c | 705 ++++++++++++++----------------------------
5 files changed, 260 insertions(+), 516 deletions(-)

--
1.7.10.4