From: "Joel Fernandes (Google)" <j...@joelfernandes.org> This series contains the last 2 patches of the previous series, with minor changes suggested by Peter and Steven, and an additional patch for get_lock_stats cleanup suggested by Peter.
The preempt/irq tracepoints exist but not everything in the kernel is using it whenever they need to be notified that a preempt disable/enable or an irq disable/enable has occurred. This makes things not work simultaneously (for example, only either lockdep or irqsoff trace-events can be used at a time). This is particularly painful to deal with, since turning on lockdep breaks tracers that install probes on IRQ events, such as the BCC atomic critical section tracer [1]. This constraint also makes it not possible to use synthetic events to trace irqsoff sections with lockdep simulataneously turned on. This series solves that, and also results in a nice clean up of relevant parts of the kernel. 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. [1] https://github.com/iovisor/bcc/pull/1801/ v9->v10: - Dropped first 3 and last 2 patches that were applied previously - Folded SPDK license into the main patch introducing trace_preemptirq.c (Steve) - Dropped lockdep_recursing & use simplify get_cpu_var instead (PeterZ) - Simplify __DO_TRACE and use rcu_dereference_raw for both RCU and SRCU (PeterZ) v8->v9: - Small style changes to tracepoint code (Mathieu) - Minor style fix to use PTR_ERR_OR_ZERO (0-day bot) - Minor fix to test_atomic_sections to use unsigned long. - Added Namhyung's, Mathieu's Reviewed-by to some patches. v7->v8: - Refactored irqsoff tracer probe defines (Namhyung) 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) (3): lockdep: use this_cpu_ptr instead of get_cpu_var stats tracepoint: Make rcuidle tracepoint callers use SRCU tracing: Centralize preemptirq tracepoints and unify their usage include/linux/ftrace.h | 11 +- include/linux/irqflags.h | 11 +- include/linux/lockdep.h | 8 +- include/linux/preempt.h | 2 +- include/linux/tracepoint.h | 45 ++++-- include/trace/events/preemptirq.h | 23 +-- init/main.c | 5 +- kernel/locking/lockdep.c | 45 ++---- kernel/sched/core.c | 2 +- kernel/trace/Kconfig | 22 ++- kernel/trace/Makefile | 2 +- kernel/trace/trace_irqsoff.c | 231 ++++++++---------------------- kernel/trace/trace_preemptirq.c | 72 ++++++++++ kernel/tracepoint.c | 16 ++- 14 files changed, 248 insertions(+), 247 deletions(-) create mode 100644 kernel/trace/trace_preemptirq.c -- 2.18.0.203.gfac676dfb9-goog
