On Fri, 24 Mar 2023 13:06:59 -0400 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Fri, 24 Mar 2023 09:43:53 -0700 > Beau Belgrave <beaub@xxxxxxxxxxxxxxxxxxx> wrote: > > > > It was actually merged in 5.8. So sysctl should be sufficient with that. > > > But maybe it's weird to start adding sysctls, when the rest of tracing > > > tunables is AFAIK under /sys/kernel/tracing/ ? > > > > > > > During the TraceFS meetings Steven runs I was asked to add a boot > > parameter and sysctl for user_events to limit the max. > > > > To me, it seems when user_events moves toward namespace awareness > > sysctl might be easier to use from within a namespace to turn knobs. > > > > Happy to change to whatever, but I want to see Steven and Masami agree > > on the approach before doing so. > > > > Steven, do you agree with Masami to move to just sysctl? > > We do have some tracing related sysctls already: > > # cd /proc/sys/kernel > # ls *trace* > ftrace_dump_on_oops oops_all_cpu_backtrace traceoff_on_warning > ftrace_enabled stack_tracer_enabled tracepoint_printk > > Although I would love to deprecated ftrace_enable as that now has a > control in tracefs, but it's not unprecedented to have tracing tunables as > sysctl. > > And if we get cmdline boot parameters for free from sysctls then all the > better. Yeah, I confirmed that sysctl can be set via kernel parameter. So it is OK for me to add a sysctl. Thank you, > > -- Steve -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
