Hello, This is the next revision of preempt/irq tracepoint centralization and unified usage across the kernel [1]. The preempt/irq tracepoints exist but not everything in the kernel is using it. This makes things not work simultaneously (for ex, only lockdep or irqsoff events can be used). This series is an attempt to solve that.
I fixed several issues since last rev and I'm posting it slightly early than I wanted to for some feedback especially for the new patches 1-3 in this series. Also any testing is deeply appreciated. Status: Currently I'm noticing a performance issue with "enabling" of the preemptoff tracer (not during its running but the enabling/startup of it). I narrowed this down to rcu_irq_enter_irqson and rcu_irq_exit_irqson calls in tracepoint.h. Commenting these out makes the perf issue go away. I also notice that disabling function tracer also makes the issue go away. Note that I ran hackbench and don't notice any performance issues with my patch itself per-se, however the preemptoff tracer startup seems slow and I'm debugging that. If you have a clue why this might be happening, please let me know. Note that I skipped v3 because I used that number already for some internal reviews of these patches. Also I changed the subject back to RFC in light of the lockdep issues I fixed this time and added some more folks for review. Thanks much for any review or testing. [1] https://www.spinics.net/lists/kernel/msg2750826.html Joel Fernandes (4): tracepoint: Add API to not do lockdep checks during RCU ops softirq: reorder trace_softirqs_on to prevent lockdep splat irqflags: Avoid unnecessary calls to trace_ if you can tracing: Centralize preemptirq tracepoints and unify their usage include/linux/ftrace.h | 11 +- include/linux/irqflags.h | 32 +++-- include/linux/lockdep.h | 8 +- include/linux/preempt.h | 2 +- include/linux/tracepoint.h | 32 ++++- 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 | 206 +++++++----------------------- kernel/trace/trace_preemptirq.c | 73 +++++++++++ 14 files changed, 229 insertions(+), 230 deletions(-) create mode 100644 kernel/trace/trace_preemptirq.c Cc: Steven Rostedt <[email protected]> Cc: Peter Zilstra <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Thomas Glexiner <[email protected]> Cc: Boqun Feng <[email protected]> Cc: Paul McKenney <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Randy Dunlap <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Fenguang Wu <[email protected]> Cc: Baohong Liu <[email protected]> Cc: Vedang Patel <[email protected]> -- 2.17.0.484.g0c8726318c-goog
