[PATCH RFC v6 0/5] Centralize and unify usage of preempt/irq tracepoints

[Joel Fernandes <joelaf@google.com>]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

This is the next revision of preempt/irq tracepoint centralization and
unified usage across the kernel.
The preempt/irq tracepoints exist but not everything in the kernel is
using it. This makes things not work simultaneously (for ex, only either
lockdep or irqsoff events can be used at a time). This series is an attempt to
solve that, and also results in a nice clean up of kernel in general.
Several ifdefs are simpler, and the design is more unified and better.
Also as a result of this, we also speeded performance all rcuidle
tracepoints since their handling is simpler.

No major changes since v5. Just some spelling errors, small refactoring
etc. Also I removed the softirq bug fix from this series and submitted it
separately.

I am also writing a tracepoint self-test that runs various tests, along
with some documentation. I am planning to submit that separately since
it'll take some time to complete them and so that these can go in first.
See [1] for a preview of the tests I have so far (its early stage).

v6:
- fixed lockdep_recursion undefined issue, now using
  lockdep_recursing().
- minor patch clean up

v5:
- Fixed performance issues due to rcu-idle handling

Joel Fernandes (Google) (4):
  srcu: Add notrace variant of srcu_dereference
  trace/irqsoff: Split reset into separate functions
  tracepoint: Make rcuidle tracepoint callers use SRCU
  tracing: Centralize preemptirq tracepoints and unify their usage

Paul McKenney (1):
  srcu: Add notrace variants of srcu_read_{lock,unlock}

 include/linux/ftrace.h            |  11 +-
 include/linux/irqflags.h          |  11 +-
 include/linux/lockdep.h           |   8 +-
 include/linux/preempt.h           |   2 +-
 include/linux/srcu.h              |  22 +++
 include/linux/tracepoint.h        |  46 +++++-
 include/trace/events/preemptirq.h |  23 +--
 init/main.c                       |   5 +-
 kernel/locking/lockdep.c          |  35 ++---
 kernel/sched/core.c               |   2 +-
 kernel/trace/Kconfig              |  22 ++-
 kernel/trace/Makefile             |   2 +-
 kernel/trace/trace_irqsoff.c      | 235 +++++++++---------------------
 kernel/trace/trace_preemptirq.c   |  71 +++++++++
 kernel/tracepoint.c               |  15 +-
 15 files changed, 282 insertions(+), 228 deletions(-)
 create mode 100644 kernel/trace/trace_preemptirq.c

[1] tracepoint-selftests: https://tinyurl.com/tptests-1

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zilstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Glexiner <tglx@linutronix.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Fenguang Wu <fengguang.wu@intel.com>
Cc: Baohong Liu <baohong.liu@intel.com>
Cc: Vedang Patel <vedang.patel@intel.com>
Cc: kernel-team@android.com
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
-- 
2.17.0.441.gb46fe60e1d-goog