Re: [PATCH v6 17/22] arm64: mm: Add page fault trace points

[Will Deacon <will@kernel.org>]

On Mon, May 19, 2025 at 12:08:37PM -0400, Steven Rostedt wrote:
> On Mon, 19 May 2025 16:12:39 +0100
> Will Deacon <will@kernel.org> wrote:
> 
> > > Perf events work for perf only. My question is why isn't this a tracepoint
> > > that perf could hook into?  
> > 
> > Well, the perf event came first in this case, so we're stuck with it :/
> 
> I wonder what effort it will take to convert perf events to tracepoints ;-)
> 
> Note, I'm talking about tracepoints and not trace events, where the
> latter is exposed to tracefs and the former is not.
> 
> > 
> > I was hoping we could settle for a generic helper that could emit both
> > the trace event and the perf event (so that the ordering of the two is
> > portable across architectures) but, judging by Nam's reply, the trace
> > event is needed before kprobes gets a look in.
> 
> Perhaps we could add a helper function that does both (perf and
> tracepoint) and hide the implementation from the code that calls it?

Something like that sounds like a good idea, yes.

> But I'm currently still on PTO so I haven't looked at the details yet.

Enjoy!

Will