Linus, As the merge window is still open, and this code was not as complex as I thought it might be. I'm pushing this in now.
This will allow Thomas to debug his irq work for 3.20. This adds two new features: 1) Allow traceopoints to be enabled right after mm_init(). By passing in the trace_event= kernel command line parameter, tracepoints can be enabled at boot up. For debugging things like the initialization of interrupts, it is needed to have tracepoints enabled very early. People have asked about this before and this has been on my todo list. As it can be helpful for Thomas to debug his upcoming 3.20 IRQ work, I'm pushing this now. This way he can add tracepoints into the IRQ set up and have users enable them when things go wrong. 2) Have the tracepoints printed via printk() (the console) when they are triggered. If the irq code locks up or reboots the box, having the tracepoint output go into the kernel ring buffer is useless for debugging. But being able to add the tp_printk kernel command line option along with the trace_event= option will have these tracepoints printed as they occur, and that can be really useful for debugging early lock up or reboot problems. This code is not that intrusive and it passed all my tests. Thomas tried them out too and it works for his needs. Link: http://lkml.kernel.org/r/20141214201609.126831...@goodmis.org Please pull the latest trace-3.19-2 tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-3.19-2 Tag SHA1: 378ef8105fed2dd3299e3232ff3d365a7d9feac9 Head SHA1: 0daa2302968c13b657118d6ac92471f8fd2f3f28 Steven Rostedt (Red Hat) (2): tracing: Move enabling tracepoints to just after rcu_init() tracing: Add tp_printk cmdline to have tracepoints go to printk() ---- Documentation/kernel-parameters.txt | 18 ++++++++++++++++ include/linux/ftrace.h | 7 +++++++ init/main.c | 4 ++++ kernel/sysctl.c | 7 +++++++ kernel/trace/trace.c | 25 +++++++++++++++++++++- kernel/trace/trace.h | 14 +++++++++++++ kernel/trace/trace_events.c | 42 +++++++++++++++++++++++++++++++++++-- kernel/trace/trace_syscalls.c | 7 ++----- 8 files changed, 116 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
