On Sat, 4 May 2019 12:47:10 -0400 Joel Fernandes <j...@joelfernandes.org> wrote:
> I agree with the general idea, but I don't really like how it is done in the > patch. +1 > > We do have a notification mechanism already in the form of trace_pipe. Can we > not improve that in some way to be notified of a new trace data? In theory, > the trace_pipe does fit into the description in the documentation: "Reads > from this file will block until new data is retrieved" > > More comment below: > > > > + config PREEMPTIRQ_FSNOTIFY > > + bool "Generate fsnotify events for the latency tracers" > > + default n > > + depends on (IRQSOFF_TRACER || PREEMPT_TRACER) && FSNOTIFY > > + help > > + This option will enable the generation of fsnotify events for the > > + trace file. This makes it possible for userspace to be notified about > > + modification of /sys/kernel/debug/tracing/trace through the inotify > > + interface. > > Does this have to be a CONFIG option? If prefer if the code automatically > does the notification and it is always enabled. I don't see any drawbacks of > that. I mentioned that anything it needs to be an option. > > +#ifdef CONFIG_PREEMPTIRQ_FSNOTIFY > > + > > +static void trace_notify_workfn(struct work_struct *work) > [snip] > > I prefer if this facility is available to other tracers as well such as > the wakeup tracer which is similar in output (check > Documentation/trace/ftrace.txt). I believe this should be a generic trace > facility, and not tracer specific. For what it's worth, I agree with everything Joel just stated. Thanks, -- Steve
