Messages in this thread | | | Date | Mon, 24 Feb 2020 17:02:31 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH v4 05/27] x86: Replace ist_enter() with nmi_enter() |
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On Mon, 24 Feb 2020 22:31:39 +0100 Peter Zijlstra <peterz@infradead.org> wrote:
> > Just want to confirm that printk_nmi_enter(), lockdep_off(), > > and ftrace_nmi_enter() are all marked fully with NOKPROBE. > > *sigh*, right you are, I only looked at notrace, not nokprobe. > > In particular the ftrace one is a bit off a mess, let me sort through > that.
ftrace_nmi_enter() has two purposes. One, for archs that need to deal with NMIs while they still use stop machine. Although, it appears sh is the only arch that does that. I can look to see if it can be ripped out.
The other is for the hwlat detector that measures the time it was in an NMI, as NMIs appear as a hardware latency too.
-- Steve
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