[PATCH RFC v4 0/3] tracing: Add trace events for preemption and irq disable/enable.

[Joel Fernandes <joelaf@google.com>]

These patches add trace events support for preempt and irq disable/enable
events.

Changes since v3 (link [1]):
Previously the patch series used the terms "critical section" but Peter
suggested that this name is confusing due to ambiguity, so I dropped calling it
that in this series. See discussion in [1]. I also dropped the "preemptirq"
combined event (which behaves similar to the preemptirqsoff tracer) for now and
will keep that for a later patch once we can get this foundation series in.

Here's an example of how Android's systrace will be using it to show atomic
sections as a gantt chart: http://imgur.com/download/TZplEVp

I also added a slightly unrelated fix for a config option (patch 3/3).

[1] https://patchwork.kernel.org/patch/9936045/

Joel Fernandes (3):
  trace/irqsoff: Prepare to add preempt and irq trace events
  trace: Add support for preempt and irq enable/disable events
  ftrace: Use correct config option for preemption debug

 include/linux/ftrace.h            |   7 +-
 include/linux/irqflags.h          |   4 +-
 include/trace/events/preemptirq.h |  62 +++++++++++++
 kernel/trace/Kconfig              |   9 ++
 kernel/trace/Makefile             |   1 +
 kernel/trace/trace_irqsoff.c      | 178 +++++++++++++++++++++++++++++++-------
 6 files changed, 226 insertions(+), 35 deletions(-)
 create mode 100644 include/trace/events/preemptirq.h

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@android.com
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2.14.1.581.gf28d330327-goog