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