[PATCH v8 0/8] Centralize and unify usage of preempt/irq tracepoints

Joel Fernandes
2018-05-30T00:05:14Z

The preempt/irq tracepoints exist but not everything in the kernel is
using it during preempt/irq on/off events. 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 the kernel in general. Several ifdefs are
simpler, and the design is more unified and better. Also as a result of
this, we also speeded up performance all rcuidle tracepoints since
their handling is simpler.

v7->v8:
- Refactored irqsoff tracer probe defines based on Namhyung's
suggestions. No functional change.

v6->v7:
- Added a module to simulate an atomic section, a kselftest to load and
and trigger it which verifies the preempt-tracer and this series.

- Fixed a new warning after I rebased in early boot, this is because
early_boot_irqs_disabled was set too early, I moved it after the lockdep
initialization.

- added back the softirq fix since it appears it wasn't picked up.

- Ran Ingo's locking API selftest suite which are passing with this
series.

- Mathieu suggested ifdef'ing the tracepoint_synchronize_unregister
function incase tracepoints aren't enabled, did that.

Joel Fernandes (Google) (7):
softirq: reorder trace_softirqs_on to prevent lockdep splat
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
lib: Add module to simulate atomic sections for testing preemptoff
tracers
kselftests: Add tests for the preemptoff and irqsoff tracers

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 | 48 +++-
include/trace/events/preemptirq.h | 23 +-
init/main.c | 5 +-
kernel/locking/lockdep.c | 35 +--
kernel/sched/core.c | 2 +-
kernel/softirq.c | 6 +-
kernel/trace/Kconfig | 22 +-
kernel/trace/Makefile | 2 +-
kernel/trace/trace_irqsoff.c | 253 ++++++------------
kernel/trace/trace_preemptirq.c | 71 +++++
kernel/tracepoint.c | 15 +-
lib/Kconfig.debug | 8 +
lib/Makefile | 1 +
lib/test_atomic_sections.c | 79 ++++++
tools/testing/selftests/ftrace/config | 3 +
.../test.d/preemptirq/irqsoff_tracer.tc | 74 +++++
21 files changed, 459 insertions(+), 242 deletions(-)
create mode 100644 kernel/trace/trace_preemptirq.c
create mode 100644 lib/test_atomic_sections.c
create mode 100644 tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc

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2.17.0.921.gf22659ad46-goog