| Date | Tue, 19 May 2020 18:23:56 -0400 | From | Steven Rostedt <> | Subject | Re: [patch V6 02/37] tracing/hwlat: Split ftrace_nmi_enter/exit() |
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On Sat, 16 May 2020 01:45:49 +0200 Thomas Gleixner <tglx@linutronix.de> wrote:
> The hardware latency tracer calls into timekeeping and ends up in > various instrumentable functions which is problematic vs. the kprobe > handling especially the text poke machinery. It's invoked from > nmi_enter/exit(), i.e. non-instrumentable code. > > Split it into two parts: > > 1) NMI counter, only invoked on nmi_enter() and noinstr safe > > 2) NMI timestamping, to be invoked from instrumentable code > > Move it into the rcu is watching regions of nmi_enter/exit() even > if there is no actual RCU dependency right now but there is also > no point in having it early. > > The actual split of nmi_enter/exit() is done in a separate step. > > Requested-by: Steven Rostedt <rostedt@goodmis.org> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-- Steve
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