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Date: Sun, 28 Dec 2025 13:31:50 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Yury Norov (NVIDIA)" <yury.norov@gmail.com>, Masami Hiramatsu
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Subject: Re: [PATCH v4 7/7] kernel.h: drop trace_printk.h
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On Fri, 26 Dec 2025 11:58:48 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:

> On Thu, 25 Dec 2025 12:09:29 -0500
> "Yury Norov (NVIDIA)" <yury.norov@gmail.com> wrote:
> 
> > The trace_printk.h header is debugging-only by nature, but now it's
> > included by almost every compilation unit via kernel.h.
> > 
> > Removing trace_printk.h saves 1.5-2% of compilation time on my
> > Ubuntu-derived x86_64/localyesconfig.
> > 
> > There's ~30 files in the codebase, requiring trace_printk.h for
> > non-debugging reasons: mostly to disable tracing on panic or under
> > similar conditions. Include the header for those explicitly.
> > 
> > This implicitly decouples linux/kernel.h and linux/instruction_pointer.h
> > as well, because it has been isolated to trace_printk.h early in the
> > series.
> > 
> > Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> 
> I'm still against this patch. It means every time someone adds
> trace_printk() they need to add the header for it.
> 
> trace_printk() should be as available to the kernel as printk() is.

um, why?  trace_printk is used 1% as often as is printk.  Seems
reasonable to include a header file to access such a rarely-used(!) and
specialized thing?