Re: [PATCH v4 05/27] x86: Replace ist_enter() with nmi_enter()

Steven Rostedt
2020-02-26T15:20:34Z

On Wed, 26 Feb 2020 11:27:58 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Mon, Feb 24, 2020 at 05:02:31PM -0500, Steven Rostedt wrote:
>
> > The other is for the hwlat detector that measures the time it was in an
> > NMI, as NMIs appear as a hardware latency too.
>
> Yeah,.. I hate that one. But I ended up with this patch.
>
> And yes, I know some of those notrace annotations are strictly
> unnessecary due to Makefile crap, but having them is _SO_ much easier.
>
> ---
> Subject: x86,tracing: Robustify ftrace_nmi_enter()
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Mon Feb 24 23:40:29 CET 2020
>
> ftrace_nmi_enter()
> trace_hwlat_callback()
> trace_clock_local()
> sched_clock()
> paravirt_sched_clock()
> native_sched_clock()
>
> All must not be traced or kprobed, it will be called from do_debug()
> before the kprobe handler.
>

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/x86/include/asm/paravirt.h | 2 +-
> arch/x86/kernel/tsc.c | 7 +++++--
> include/linux/ftrace_irq.h | 4 ++--
> kernel/trace/trace_clock.c | 2 ++
> kernel/trace/trace_hwlat.c | 4 +++-
> 5 files changed, 13 insertions(+), 6 deletions(-)
>